## 1. Why is intentionality so-called?



Contemporary discussions of the nature of intentionality are an
integral part of discussions of the nature of minds: what are minds
and what is it to have a mind? They arise in the context of
ontological and metaphysical questions about the fundamental nature of
mental states: states such as perceiving, remembering, believing,
desiring, hoping, knowing, intending, feeling, experiencing, and so
on. What is it to have such mental states? How does the mental relate
to the physical, i.e., how are mental states related to an
individual's body, to states of his or her brain, to his or her
behavior and to states of affairs in the world?



Why is intentionality so-called? For reasons soon to be explained, in
its philosophical usage, the meaning of the word
'intentionality' should not be confused with the ordinary
meaning of the word 'intention.' As indicated by the
meaning of the Latin word *tendere*, which is the etymology of
'intentionality,' the relevant idea behind intentionality
is that of mental directedness towards (or attending to) objects, as
if the mind were construed as a mental bow whose arrows could be
properly aimed at different targets. In medieval logic and philosophy,
the Latin word *intentio* was used for what contemporary
philosophers and logicians nowadays call a 'concept' or an
'intension': something that can be both true of non-mental
things and properties--things and properties lying outside the
mind--and present to the mind. On the assumption that a concept
is itself something mental, an *intentio* may also be true of
mental things. For example, the concept of a dog, which is a
first-level *intentio*, applies to individual dogs or to the
property of being a dog. It also falls under various higher-level
concepts that apply to it, such as being a concept, being mental, etc.
If so, then while the first-level concept is true of non-mental
things, the higher-level concepts may be true of something mental.
Notice that on this way of thinking, concepts that are true of mental
things are presumably logically more complex than concepts that are
true of non-mental things.



Although the meaning of the word 'intentionality' in
contemporary philosophy is related to the meanings of such words as
'intension' (or 'intensionality' with an
*s*) and 'intention,' nonetheless it ought not to
be confused with either of them. On the one hand, in contemporary
English, 'intensional' and 'intensionality'
mean 'non-extensional' and
'non-extensionality,' where both extensionality and
intensionality are logical features of words and sentences. For
example, 'creature with a heart' and 'creature with
a kidney' have the same extension because they are true of the
same individuals: all the creatures with a kidney are creatures with a
heart. But the two expressions have different intensions because the
word 'heart' does not have the same extension, let alone
the same meaning, as the word 'kidney.' On the other hand,
intention and intending are specific states of mind that, unlike
beliefs, judgments, hopes, desires or fears, play a distinctive role
in the etiology of actions. By contrast, intentionality is a pervasive
feature of many different mental states: beliefs, hopes, judgments,
intentions, love and hatred all exhibit intentionality. In fact,
Brentano held that intentionality is the hallmark of the mental: much
of twentieth century philosophy of mind has been shaped by what, in
this entry, will be referred to as "Brentano's third
thesis."



Furthermore, it is worthwhile to distinguish between levels of
intentionality. Many of an individual's psychological states
with intentionality (e.g., beliefs) are about (or represent)
non-mental things, properties and states of affairs. Many are also
about another's psychological states (e.g., another's
beliefs). Beliefs about others' beliefs display what is known as
'higher-order intentionality.' Since the seminal (1978)
paper by primatologists David Premack and Guy Woodruff entitled
"Does the chimpanzee have a theory of mind?", under the
heading 'theory of mind,' much empirical research of the
past thirty years has been devoted to the psychological questions
whether non-human primates can ascribe psychological states with
intentionality to others and how human children develop their capacity
to ascribe to others psychological states with intentionality (cf. the
comments by philosophers Jonathan Bennett, Daniel Dennett and Gilbert
Harman to Premack and Woodruff's paper and the SEP entry
 folk psychology: as a theory).



The concept of intentionality has played a central role both in the
tradition of analytic philosophy and in the phenomenological
tradition. As we shall see, some philosophers go so far as claiming
that intentionality is characteristic of *all* mental states.
Brentano's characterization of intentionality is quite complex.
At the heart of it is Brentano's notion of the
'intentional inexistence of an object,' which is analyzed
in the next section.


## 2. Intentional inexistence



Contemporary discussions of the nature of intentionality were launched
and many of them were anticipated by Franz Brentano (1874,
88-89) in his book, *Psychology From an Empirical
Standpoint*, from which I quote two famous paragraphs:



> 
> Every mental phenomenon is characterized by what the Scholastics of
> the Middle Ages called the intentional (or mental) inexistence of an
> object, and what we might call, though not wholly unambiguously,
> reference to a content, direction toward an object (which is not to be
> understood here as meaning a thing), or immanent objectivity. Every
> mental phenomenon includes something as object within itself, although
> they do not do so in the same way. In presentation, something is
> presented, in judgment something is affirmed or denied, in love loved,
> in hate hated, in desire desired and so on.
> 
> 
> This intentional inexistence is characteristic exclusively of mental
> phenomena. No physical phenomenon exhibits anything like it. We can,
> therefore, define mental phenomena by saying that they are those
> phenomena which contain an object intentionally within themselves.
> 
> 
> 



As one reads these lines, numerous questions arise: what does Brentano
mean when he says that the object towards which the mind directs
itself 'is not to be understood as meaning a thing'? What
can it be for a phenomenon (mental or otherwise) to exhibit 'the
intentional inexistence of an object'? What is it for a
phenomenon to 'include something as object within itself'?
Do 'reference to a content' and 'direction toward an
object' express two distinct ideas? Or are they two distinct
ways of expressing one and the same idea? If intentionality can relate
a mind to something that either does not exist or exists wholly within
the mind, what sort of relation can it be?



Replete as they are with complex, abstract and controversial ideas,
these two short paragraphs have set the agenda for all subsequent
philosophical discussions of intentionality in the late nineteenth and
the twentieth century. There has been some discussion over the meaning
of Brentano's expression 'intentional inexistence.'
Did Brentano mean that the objects onto which the mind is directed are
*internal* to the mind itself (*in*-exist in the mind)?
Or did he mean that the mind can be directed onto
*non*-existent objects? Or did he mean both? (See Crane, 1998
for further discussion.)



Some of the leading ideas of the phenomenological tradition can be
traced back to this issue. Following the lead of Edmund Husserl (1900,
1913), who was both the founder of phenomenology and a student of
Brentano's, the point of the phenomenological analysis has been
to show that the essential property of intentionality of being
directed onto something is *not* contingent upon whether some
real physical target exists independently of the intentional act
itself. To achieve this goal, two concepts have been central to
Husserl's internalist interpretation of intentionality: the
concept of a *noema* (plural *noemata*) and the concept
of *epoche* (i.e., bracketing) or phenomenological reduction.
By the word 'noema,' Husserl refers to the internal
structure of mental acts. The phenomenological reduction is meant to
help get at the essence of mental acts by suspending all naive
presuppositions about the difference between real and fictitious
entities (on these complex phenomenological concepts, see the papers
by Follesdal and others conveniently gathered in Dreyfus
(1982). For further discussion, see Bell (1990) and Dummett
(1993).



In the two paragraphs quoted above, Brentano sketches an entire
research programme based on three distinct theses. According to the
first thesis, it is constitutive of the phenomenon of intentionality,
as it is exhibited by mental states such as loving, hating, desiring,
believing, judging, perceiving, hoping and many others, that these
mental states are directed towards things different from themselves.
According to the second thesis, it is characteristic of the objects
towards which the mind is directed by virtue of intentionality that
they have the property which Brentano calls intentional inexistence.
According to the third thesis, intentionality is the mark of the
mental: all and only mental states exhibit intentionality.



Unlike Brentano's third thesis, Brentano's first two
theses can hardly be divorced from each other. The first thesis can
easily be recast so as to be unacceptable unless the second thesis is
accepted. Suppose that it is constitutive of the nature of
intentionality that one could not exemplify such mental states as
loving, hating, desiring, believing, judging, perceiving, hoping, and
so on, unless there was *something* to be loved, hated,
desired, believed, judged, perceived, hoped, and so on. If so, then it
follows from the very nature of intentionality (as described by the
first thesis) that nothing could exhibit intentionality unless there
were *objects*--intentional objects--that satisfied
the property Brentano called intentional inexistence.



Now, the full acceptance of Brentano's first two theses raises a
fundamental ontological question in philosophical logic. The question
is: are there such intentional objects? Does due recognition of
intentionality force us to postulate the ontological category of
intentional objects? This question has given rise to a major division
within analytic philosophy. The prevailing (or orthodox) response has
been a resounding 'No.' But an important minority of
philosophers, whom I shall call 'the intentional-object'
theorists, have argued for a positive response to the question. Since
intentional objects need not exist, according to intentional-object
theorists, there are things that do not exist. According to their
critics, there are no such things.



We shall directly examine the intentional-object theorists approach in
section 7. Before doing so, in section 3, we shall examine the way
singular thoughts about concrete particulars in space and time can be
and have been construed as paradigms of genuine intentional relations.
On this relational construal, an individual's ordinary singular
thought about a concrete physical particular involves a genuine
relation between the individual's mind and the concrete physical
particular. In sections 4-5, we shall examine two puzzles that
further arise on the orthodox paradigm. First, we shall deal with the
puzzle of how a rational person can believe of an object referred to
by one singular term that it instantiates a property and
simultaneously disbelieve of the same object referred to by a distinct
singular term that it instantiates the same property. Section 4 is
devoted to Frege's solution to this puzzle. In section 5, we
shall scrutinize Russell's solution to the puzzle of true
negative existential statements. In section 6, we shall see how the
theory of direct reference emerged within the orthodox paradigm out of
a critique of both Frege's notion of sense and Russell's
assumption that most proper names in natural languages are disguised
definite descriptions.


## 3. The relational nature of singular thoughts



Many non-intentional relations hold of concrete particulars in space
and time. If and when they do, their relata cannot fail to exist. If
Cleopatra kisses Caesar, then both Cleopatra and Caesar must exist.
Not so with intentional relations. If Cleopatra loves Caesar, then
presumably there is some concrete particular in space and time whom
Cleopatra loves. But one may also love Anna Karenina (not a concrete
particular in space and time, but a fictitious character). Similarly,
the relata of the admiration relation (another intentional relation)
are not limited to concrete particulars in space and time. One may
admire not only Albert Einstein but also Sherlock Holmes (a fictitious
character). As the following passage from the Appendix to the 1911
edition of his 1874 book testifies, this asymmetry between
non-intentional and intentional relations puzzled Brentano:



> 
> What is characteristic of every mental activity is, as I believe I
> have shown, the reference to something as an object. In this respect,
> every mental activity seems to be something relational. [...] In
> other relations both terms--both the fundament and the
> terminus--are real, but here only the first term--the
> fundament is real. [...] If I take something relative [...]
> something larger or smaller for example, then, if the larger thing
> exists, the smaller one exists too. [...] Something like what is
> true of relations of similarity and difference holds true for
> relations of cause and effect. For there to be such a relation, both
> the thing that causes and the thing that is caused must exist.
> [...] It is entirely different with mental reference. If someone
> thinks of something, the one who is thinking must certainly exist, but
> the object of his thinking need not exist at all. In fact, if he is
> denying something, the existence of the object is precisely what is
> excluded whenever his denial is correct. So the only thing which is
> required by mental reference is the person thinking. The terminus of
> the so-called relation does not need to exist in reality at all. For
> this reason, one could doubt whether we really are dealing with
> something relational here, and not, rather, with something somewhat
> similar to something relational in a certain respect, which might,
> therefore, better be called "quasi-relational."
> 



While the orthodox paradigm is clearly consistent with the possibility
that general thoughts may involve abstract objects (e.g., numbers) and
abstract properties and relations, none of which are in space and
time, special problems arise with respect to singular thoughts
construed as intentional relations to non-existent or fictitious
objects. Two related assumptions lie at the core of the orthodox
paradigm. One is the assumption that the mystery of the intentional
relation should be elucidated against the background of
non-intentional relations. The other is the assumption that
intentional relations which seem to involve non-existent (e.g.,
fictitious) entities should be clarified by reference to intentional
relations involving particulars existing in space and time.



The paradigm of the intentional relation that satisfies the orthodox
picture is the intentionality of what can be called *singular*
thoughts, namely those true thoughts that are directed towards
concrete individuals or particulars that exist in space and time. A
singular thought is such that it would not be available--it could
not be entertained--unless the concrete individual that is the
target of the thought existed. Unlike the propositional contents of
*general* thoughts that involve only abstract universals such
as properties and/or relations, the propositional content of a
singular thought may involve in addition a relation to a concrete
individual or particular. The contrast between 'singular'
and 'general' propositions has been much emphasized by
Kaplan (1978, 1989). In a slightly different perspective, Tyler Burge
(1977) has characterized singular thoughts as incompletely
conceptualized or *de re* thoughts whose relation to the
objects they are about is supplied by the context. On some views, the
object of the singular thought is even *part* of it. On the
orthodox view, part of the importance of true singular thoughts for a
clarification of intentionality lies in the fact that some true
singular thoughts are about concrete perceptible objects. Singular
thoughts about concrete perceptible objects may seem simpler and more
primitive than either general ones or thoughts about abstract
entities.



Consider, for example, what must be the case for belief-ascription (1)
to be true:


1. Ava believes that Lionel Jospin is a Socialist.



Intuitively, the belief ascribed to Ava by (1) has intentionality in
the sense that it is *of* or *about* Lionel Jospin and
the property of being a Socialist. Besides being a belief (i.e., a
special *attitude* different from a wish, a desire, a fear or
an intention), the identity of Ava's belief depends on its
propositional content. What Ava believes is identified by the embedded
'that'-clause that can stand all by itself as in (2):


2. Lionel Jospin is a Socialist.



On the face of it, an utterance of (2) is true if and only if a given
concrete individual does exemplify the property of being a Socialist.
Arguably, it is essential to the proposition that Ava
believes--the proposition expressed by an utterance of
(2)--that it is about Jospin and the property of being a
Socialist. Just by virtue of having such a true belief, Ava must
therefore stand in relation--the belief relation--to Jospin
and the property of being a Socialist. Notice that Ava can have a
belief about Jospin and the property of being a Socialist even though
she has never seen Jospin in person.



From within the orthodox paradigm, one central piece of the mystery of
intentionality can be brought out by reflection on the conditions in
which simple singular thoughts about concrete individuals are true.
This is the problem of the *relational* nature of the contents
of true singular beliefs. In order to generate this problem, it is not
necessary to ascend to false or abstract beliefs about fictional
entities. It is enough to consider how a true thought about a concrete
individual that exists in space and time can arise. On the one hand,
Ava's belief seems to be a singular belief about a concrete
individual. It seems essential to Ava's belief that it has the
propositional content that it has. And it seems essential to the
propositional content of Ava's belief that Ava must stand in
relation to somebody else who can be very remote from her in either
space or time. On the other hand, Ava's belief is a state
internal to Ava. As John Perry (1994, 187) puts it, beliefs and other
so-called 'propositional attitudes' seem to be
"local mental phenomena." How can it be essential to an
internal state of Ava's that Ava stands in relation to someone
else? How can one reconcile the local and the relational characters of
propositional attitudes?


## 4. How can distinct beliefs be about one and the same object?



The problem of the relational nature of the contents of true singular
thoughts can be made more acute by the following puzzle that exercised
Gottlob Frege (1892): how can one rationally hold *two*
distinct singular beliefs that are both about one and the same object?
As we shall see momentarily, this puzzle is related to a second
puzzle: the puzzle of how a statement expressing a belief about
identity can both be true and informative. If the belief relation is a
genuine relation, then it would seem that it is like *kicking*:
if Jacques Chirac kicked Lionel Jospin and if Lionel Jospin was the
French Prime minister in 2001, then Jacques Chirac kicked the French
Prime minister in 2001. Not so with belief, as we shall see
momentarily. Notice that in ordinary contexts, the word
'belief' can be used to denote either a person's
state or the content of that state.



Ever since Frege, it has been standard practice in analytic philosophy
to investigate the intentional structure of much human thought by
inquiring into the logical structure of the language used by speakers
to express it or to ascribe it to others. (See, e.g., Dummett (1973)
for a forceful justification.) Suppose that Ava correctly believes
that Hesperus is shining as a result of seeing that Hesperus shines.
Suppose also that she fails to believe that Phosphorus is shining
because, although she correctly believes that Hesperus is called
'Hesperus,' she incorrectly believes that
'Phosphorus' is the name of a different planet (that she
is not currently seeing) and she fails to know that
'Phosphorus' is in fact another name for Hesperus. So
whereas the first belief report is true, the second belief report is
false:


3. Ava believes that Hesperus is shining.
4. Ava believes that Phosphorus is shining.



Given that 'Hesperus' and 'Phosphorus' are
just names of the same object, how can Ava believe one thing and
disbelieve the other? Given that 'Hesperus' and
'Phosphorus' apply to the same object, it would seem that
'Hesperus is shining' is true if and only if
'Phosphorus is shining' is true and that these two
sentences express one and the same proposition. If what is essential
to the proposition that Ava believes is that it is about Hesperus and
the property of shining, how can she believe one thing and fail to
believe the other since both are about Hesperus?



Another related puzzle is the puzzle of how identity statements can
both be true and informative. It seems clear that Ava could not doubt
that 'Hesperus is Hesperus' expresses a truth. But it
seems clear that she can--in fact she does--doubt that
'Hesperus is Phosphorus' expresses a truth. In fact, when
she learns that 'Hesperus is Phosphorus' does express a
truth, she is surprised. How can it be? (See Richard 1990 and Salmon
1986.)



Frege (1892) offered a very influential solution to both puzzles. This
common solution is based on his famous distinction between the
*reference* (or *Bedeutung*) and the *sense* (or
*Sinn*) of an English proper name. The sense, which is the mode
of presentation of the reference, is presumably something abstract
that can both be instantiated by a concrete individual and present to,
or grasped by, a mind. This distinction is in some ways reminiscent of
the distinction between extension and intension and is inconsistent
with John Stuart Mill's (1884) view that proper names have a
denotation and no connotation.



The reason (3) and (4) can, on Frege's view, have different
truth-values is that the embedded sentences or
'that'-clauses in (3) and (4)--namely (5) and
(6)--do *not* express one and the same proposition. They
express different propositions (or thoughts). Frege uses the German
*Gedanke* for 'thought.'


5. Hesperus is shining.
6. Phosphorus is shining.



How can (5) and (6) express different propositions? Unlike
non-ordinary contexts such as (3) and (4), in which they are part of
an embedded 'that'-clause, in ordinary contexts such as
(5) and (6), 'Hesperus' and 'Phosphorus' have
the same *Bedeutung* (or reference). But they have different
senses (*Sinn*) or different modes of presentation of their
common reference. On the Fregean view, what is essential to the
thought or proposition expressed by an utterance of a sentence
containing a singular term is its *sense*, not its reference.
Propositions have senses, not individuals, as constituents. Ava lacks
a piece of knowledge. But given that ignorance is not irrationality,
Ava can rationally believe that Hesperus is shining and fail to
believe that Phosphorus is shining. Similarly, a statement expressing
a belief about identity can both be true and informative because the
two singular terms that flank the identity sign in an identity
statement have both a sense and a reference. The identity statement is
true because they have the same reference. It is informative because
they have different senses or they present their common reference via
different modes of presentation.



On the Fregean view, in (3) and (4), 'Hesperus' and
'Phosphorus' do not have their ordinary reference (or
*Bedeutung*), namely the planet to which they both apply: they
have an 'oblique' reference. In (3), the oblique reference
of 'Hesperus' is its ordinary sense. In (4), the oblique
reference of 'Phosphorus' is its ordinary sense. And we
already agreed that 'Hesperus' and
'Phosphorus' in (5) and (6) have different ordinary
senses. So in (3), 'Hesperus' has an 'oblique'
or 'indirect' sense, which is the mode of presentation of
the ordinary sense 'Hesperus' has in (5). Similarly, in
(4) 'Phosphorus' has an 'oblique' sense, which
is the mode of presentation of the ordinary sense
'Phosphorus' has in (5). On the Fregean view, a thought or
belief can be *about* a concrete individual (its reference),
but what matters to the individuation (or the identity) of the
thought's content is not the reference of the singular term, but
the sense or mode of presentation of the reference, i.e., something
abstract. For further discussion, see the entry on
 Gottlob Frege.


## 5. True negative existential beliefs



When Brentano reflected on the "quasi-relational" nature
of the intentionality of thoughts about things that need *not*
exist, he wrote that if one "is denying something, the existence
of the object is precisely what is excluded whenever [one's]
denial is correct". He thus assumed that one can correctly and
coherently deny the existence of things that do not exist. To show
that one can do so, however, is no easy task. The version of the
puzzle that exercised both Alexius Meinong (a disciple of
Brentano's) and Bertrand Russell at the turn of the twentieth
century is the puzzle of true negative existential beliefs. How can a
person correctly believe that Pegasus does not exist? For a person to
correctly believe that Pegasus does not exist, she must have a belief
whose content is the same as the content expressed by a true utterance
of sentence (7).


7. Pegasus does not exist.



How can the proposition expressed by an utterance of (7) be both true
and about Pegasus? The puzzle arises from the observation that if the
proposition is true, then presumably it is not about Pegasus since it
says that Pegasus does not exist. Conversely, if it is about Pegasus,
then Pegasus must exist. But if so, then it cannot be true since it
denies the existence of Pegasus. Thus, the puzzle has the form of a
dilemma: either the proposition expressed by (7) is false or it is not
about Pegasus. At least, the puzzle is generated by the pair of
assumptions that 'Pegasus' is a proper name and that
proper names *must* have a reference. Is the first assumption
right?



In his 1905 paper, "On denoting," Russell embraced the
view that neither 'Pegasus' nor in fact most proper names
of natural languages are genuine 'logical' proper names.
He held the epistemological view that unless one is directly
*acquainted* with something, one cannot use in thought or
language a genuine 'logical' proper name referring to it.
Nor can one entertain a genuine singular thought about it. If one is
not directly acquainted with an object, then one must instead form a
general thought that is not about any particular individual. In fact,
Russell (1911, 1919) held a dual view of acquaintance: on the one
hand, he thought that acquaintance is a relation that can only hold
between someone's mind and his or her own sense data. On the
other hand, he held the view that one can be acquainted with
universals (such as e.g., colors). If most--if not
all--names of natural languages are not genuine
'logical' names, then what are they and what is their
function in human thought and communication? On Russell's view,
they are "disguised" or abbreviated definite descriptions,
i.e., they are short for some definite description. Their logical
function is that of a definite description.



On the face of it, the grammatical form of the quasi-English sentence
'the F is G' indicates that it serves to express a
subject-predicate (or singular) proposition true if and only if the
object that exemplifies the property expressed by predicate
'F' also exemplifies the property expressed by predicate
'G'. But Russell (1905) designed a method--his famous
theory of definite descriptions--for eliminating the English
definite article 'the' (as in 'the F') by
means of a logical formula of first-order logic involving only
quantifiers and variables. On his analysis, 'the F is G'
can be paraphrased into the general existentially quantified
proposition (8):


8. [?]*x*[*Fx* &
[?]*y*(*Fy* - *y=x*) &
*Gx*]



(8) is true if and only if there is one and only one individual that
is *F* and *G*. This proposition will be false just in
case nothing or more than one thing is both *F* and
*G*.



Combined with the assumption that 'Pegasus' is not a name
but a disguised definite description--that it is short for e.g.,
'the winged horse'--Russell's theory of
definite descriptions thus leads to a solution to the puzzle of true
negative existential beliefs. The solution is to accept the second
horn of the dilemma: the proposition is not about Pegasus. On this
account, one can correctly believe that Pegasus does not exist, since
what one believes is what is expressed by an utterance of (7), namely
the true proposition that there does not exist a unique individual
that is a winged horse. Clearly, Russell's solution to the
puzzle of true negative existential beliefs shows how, in
Brentano's own terms, "if someone thinks of something, the
one who is thinking must certainly exist, but the object of his
thinking need not exist at all" and furthermore the thought may
be true. For further discussion, see the entry on
 Bertrand Russell.


## 6. Direct reference



Within the orthodox paradigm in the philosophy of mind and language of
the 1960's and 1970's, there was an important swing of the
pendulum away from the implications of Frege's and especially
Russell's doctrines for intentionality. The so-called
"theory of direct reference" has contributed to
rehabilitate the view that concrete individuals matter more to the
identity of the singular thoughts that humans entertain than the
Frege/Russell doctrines allow. According to Frege's distinction
between sense and reference, what matters to the identity of a thought
about a concrete individual is not the individual thought about but
the abstract sense by means of which he is thought about. According to
Russell, most thoughts that seem prima facie to be about concrete
individuals are in fact not singular thoughts but generally quantified
propositions. Much of the impetus for the theory of direct reference
came from the implications of the semantics of modal logic for the
intentionality of singular thoughts and beliefs.



Saul Kripke (1972) noticed an important difference between the
behavior of a proper name and the behavior of a coreferential definite
description expressing a contingent or non-essential property of its
referent, in modal contexts. Consider two sentences (9) and (10), each
containing some modal operator like 'might' (that
expresses a possibility) and such that the former contains a proper
name while the latter contains a coreferential definite
description:


9. Jacques Chirac might have been a Socialist.
10. The president of France elected in 2002 might have a been a
Socialist.



The definite description 'the president of France elected in
2002' happens to be true of Jacques Chirac of whom it expresses
a contingent property. There certainly exists a metaphysically
possible world in which either Chirac was not a candidate in the 2002
French presidential elections or he was a candidate but he lost the
election.



An utterance of (9) asserts that there exists a possible world in
which Jacques Chirac is a member of the Socialist party, which he in
fact is not. Given the deep connection between the speech act of
assertion and speaker's belief, an utterance of (9) expresses
the counterfactual belief about Chirac that he could have been a
Socialist. Unlike an utterance of (9), an utterance of (10) is
ambiguous. On one reading, it has the same truth-conditions as does an
utterance of (9) and it serves to express the same belief.
Alternatively, an utterance of (10) says of someone who is in fact a
Socialist, and who therefore is not Chirac, that he could have been
elected president in 2002.



Thus, the following contrast emerges. An utterance of (9) can only
serve to express a counterfactual belief or thought about Chirac,
i.e., the belief ascribing to Chirac the counterfactual property of
being a Socialist. An utterance of (10) can serve to express the same
belief about Chirac. But it can also serve to express an entirely
different counterfactual belief about a different individual, who as a
matter of fact happens to be a Socialist. This different
counterfactual belief would be true e.g., in a possible world in which
Jospin (who is a Socialist) won the 2002 presidential elections.



On the basis of the fact that, unlike (9), (10) can serve to express
two distinct counterfactual beliefs, Kripke (1972) hypothesizes that a
proper name is what he calls a *rigid designator*.
'Jacques Chirac' in (9) is rigid for in all possible
worlds it refers to one and the same concrete individual, i.e., the
individual to whom it in fact refers in the actual world. By contrast,
the definite description 'the president of France elected in
2002', which happens to express a contingent property of Chirac,
is not a rigid designator because it does not pick one and the same
individual in all possible worlds. When evaluated with respect to
different worlds, it is true of different individuals. Of course, some
definite descriptions (e.g., 'the square root of 21') do
express essential properties of what they are true of (in this case, a
number). According to Kripke (1980), unlike proper names, whose
rigidity is *de jure*, definite descriptions expressing
essential properties of an object are rigid *de facto*. For
further discussion, see the entry on
 reference.



Arguably, the goal of the theory of direct reference is to emphasize
the depth of the gap between the intentionality of singular thoughts
and the intentionality of general thoughts. Concrete individuals are
not constituents of the contents of the latter. But they are
constituents of the contents of the former. Three arguments have been
buttressed to dismantle the Russellian disdain for the peculiar
intentionality of singular thoughts expressible by proper names: a
modal argument, an epistemological argument and what can be called a
"transcendental" argument.



According to the modal argument, if the proper name
'Cicero' were just short for some definite description,
e.g., 'the Roman orator who denounced Catiline,' then it
would follow that the sentence 'Cicero is the Roman orator who
denounced Catiline' would express a *necessary* truth,
i.e., a proposition true in all possible worlds. But this seems
absurd: there certainly is a possible world in which Cicero did not
denounce Catiline.



According to the epistemological argument, from the same assumption,
it follows that the sentence 'Cicero is the Roman orator who
denounced Catiline' expresses a proposition knowable *a
priori*, so that it makes no sense to imagine that historians may
discover by empirical research that in fact somebody else denounced
Catiline or that nobody did. But this too seems absurd.



Finally, according to the transcendental argument, people use proper
names in thought and in verbal communication to track, pick out and
exchange valuable information about concrete particulars. Although
they may lack information expressible by some definite
description--let alone by a single definite description--for
uniquely identifying many concrete particulars, still people manage to
secure reference to them. Furthermore, as a person comes to learn more
and more information about an object or a person, she comes to
associate different definite descriptions to the referent of a proper
name. If follows that no one definite description seems suitable to
capture the content of a proper name.



According to the theory of direct reference, the function of such
linguistic devices as proper names, indexicals and demonstratives is
to introduce a concrete individual or particular into the proposition
and/or belief expressed. To use David Kaplan's (1979, 387)
revealing word, a concrete individual is "trapped" within
a singular proposition. The theory of direct reference seems like a
useful antidote against the Frege/Russell tendency to minimize the
contribution of concrete particulars to the individuation of human
singular thoughts. Three trends of thoughts in recent philosophy of
mind and language have built on the theory of direct reference. First,
many of the insights of the theory of direct reference have been
extended from thoughts about concrete individuals to thoughts about
natural kinds by Kripke (1972) and Putnam (1974). This extension plays
a crucial role in the externalist view of intentional mental states
(about which see
 section 10).
 Secondly, neo-Fregeans have responded to the challenge of the theory
of direct reference by providing a suitable notion of
"object-dependent" or "*de re*" sense
(see Evans, 1982 and McDowell, 1984). (For a response to Frege's
puzzle about how two distinct beliefs can be about the same object on
behalf of the theory of direct reference, see Salmon, 1986). Thirdly,
the metaphysical and epistemological underpinnings of singular
thoughts (and singular propositions) have given rise to a rich
discussion of the contrast between two broad perspectives:
descriptivism and singularism. According to descriptivism, we can only
think about objects by thinking about the properties which they
instantiate. But according to singularism, not all thoughts about
objects are mediated by thoughts about their properties. For further
discussion, see the papers collected in Jeshion (ed.) (2010), in
particular Recanati (2010).


## 7. Are there intentional objects?



Sections 4, 5 and 6 described three moves made within the orthodox
paradigm in analytic philosophy in response to puzzles raised by the
intentionality of singular thoughts about concrete particulars. In
particular, the dispute between the theory of direct reference and
either the Fregean distinction between sense and reference or the
Russellian assumption that ordinary proper names are disguised
definite descriptions can be seen as internal to the orthodox paradigm
according to which there are only existing objects, i.e., concrete
particulars in space and time. Brentano, however, sketched the
possibility of an alternative paradigm based on the acceptance of the
view that intentional objects may be non-existent objects or abstract
objects. (For a general survey of the role of Brentano in the
emergence of the non-orthodox theory of intentional objects in
Austrian philosophy, see Smith, 1994.)



To see how the theory of intentional objects flows from
Brentano's characterization of intentionality, recall (from
section 2) that it follows from the nature of intentionality (as
described by Brentano's first thesis) that nothing could exhibit
intentionality unless there were objects - intentional objects
- that satisfied the property Brentano called "intentional
inexistence." Consider the following inference schema licensed
by the rule of existential generalization and instantiated by the
non-intentional relation expressed by the English verb
"kiss" in (11):



> 
> 11a. Cleopatra kissed Caesar.
>   
> 
> 11b. Cleopatra kissed something.
> 



If (11a) is true, so is (11b). The question is: is this valid
inference schema also instantiated by the following pairs (12)-(15)
involving intentional relations?



> 
> 12a. Cleopatra loved Caesar.
>   
> 
> 12b. Cleopatra loved something.
> 
> 
> 13a. The Ancient Greeks worshiped Zeus.
>   
> 
> 13b. The Ancient Greeks worshiped something.
> 
> 
> 
> 14a. Ponce de Leon searched for the fountain of youth.
>   
> 
> 14b. Ponce de Leon searched for something.
> 
> 
> 
> 15a. Modern criminologists admire Sherlock Holmes.
>   
> 
> 15b. Modern criminologists admire something.
> 
> 
> 



On the one hand, unlike (11), (12)-(15) involve intentional relations.
On the other hand, unlike the intentional relation in (12), the
intentional relations in (13)-(15) seem to involve particulars which
don't exist (or haven't existed) in space and time.
Intentional-object theorists hold that the above inferences involving
both non-intentional and intentional relations constitute data that
call for a consistent explanation. In other words, the
intentional-object theorist accepts, whereas his critic rejects, the
validity of the rule of existential generalization for both
intentional and non-intentional relations, whether the relata of the
intentional relations are concrete particulars in space and time or
not. On the non-orthodox assumption that the inference schema
instantiated by (11) can be instantiated by (12)-(15) as well, then in
logical notation, the second coordinate of every pair (11)-(15) should
be symbolized thus:



> 
> 11c. [?]*x*(Cleopatra kissed *x*)
>   
> 
> 12c. [?]*x*(Cleopatra loved *x*)
>   
> 
> 13c. [?]*x*(Ancient Greeks worshiped *x*)
>   
> 
> 14c. [?]*x*(Ponce de Leon searched for *x*)
>   
> 
> 15c. [?]*x*(Modern criminologists admire *x*)
> 



Thus, the issue between the intentional-object theorist and his critic
is whether the variable bound by the standard existential quantifier
of first-order logic should range not merely over concrete particulars
existing in space and time but also over all sorts of other entities
as well. Note that the issue is orthogonal to the contrast between the
objectual and the substitutional interpretation of the existential
quantifier since the dispute over the admission of intentional objects
is wholly internal to the objectual interpretation of the quantifier.
The question that arises for the intentional-object theorist is: what
is the best theory of the objects over which (13c)-(15c) seem to
quantify?



Meinong (1904) supposed that objects like Zeus, the fountain of youth,
Sherlock Holmes, etc., are non-existent objects which exemplify the
properties attributed to them. On his view, the fountain of youth is
an object that instantiates both the property of being a fountain and
that of having waters which confer everlasting life. But it fails to
instantiate the property of existence. Meinong seemed to suppose that
for any group of properties, there is an object which instantiates
those properties. Some of the resulting objects exist and others do
not. Russell (1905) found this view of intentional objects
ontologically unacceptable since it involves the acceptance of
entities such as golden mountains (which are inconsistent with
physical and chemical laws) and round squares (which are inconsistent
with the laws of geometry). His theory of definite descriptions was
precisely designed to avoid these ontological consequences (see
section 5). However, by clarifying distinctions proposed by both
Meinong and his student Ernst Mally, Parsons (1980) has recently
offered a theory of non-existent objects, which is based on the
assumption that existence is a special kind of property. This theory
uses a quantifier "[?]", which does not imply
existence. To assert existence, he uses the predicate
"*E!*". Thus, the assertion that there are
non-existent objects can be represented in Parsons' theory
without contradiction by the logical formula
"[?]*x*(~*E!x*)." Furthermore, Parsons
distinguishes between "nuclear" and
"extranuclear" properties. Only the former, which are
ordinary, non-intentional kinds of properties, contribute to
individuating objects. The set of extranuclear properties involve
intentional properties, modal properties and existence. Armed with
this distinction among properties, Parsons (1980) has been able to
avoid Russell's objections to Meinong's naive theory of
intentional objects. (For further details, see Parsons, 1980.) An
original account of the possibility of entertaining true thoughts
about non-existent objects, based on the contrast between pleonastic
(or representation-dependent) and non-pleonastic (natural or
substantial) properties, has been developed by Crane (2013).



The theory of intentional objects has also been developed in a
slightly different way. Meinong's student Ernst Mally (1912)
proposed that fictional and mythical objects, as well as objects like
round squares, do not instantiate the properties attributed to them
but "have" those properties in a different way. For Mally,
the fountain of youth is "determined" by the properties of
being a fountain and having waters which confer everlasting life, but
this object doesn't instantiate those properties in the
traditional sense. Given Mally's distinction, the fact that
there is an object which is determined by the properties of being
golden and of being a mountain does not contradict the contingent fact
that nothing instantiates these two properties, nor does Mally have to
think of intentional objects as non-existent. Rather, he treats them
as existing abstract objects. Thus, whereas Parsons uses two kinds of
properties to develop a theory of non-existent objects, a neo-Mallyan
such as Zalta (1988) uses two kinds of predication -
exemplification (which corresponds to instantiation) and encoding
(which corresponds to Mally's notion of determination) -
to develop a theory of abstract objects. These abstract objects are
part of the explanations of both the truths expressed by (13a)-(15a)
and the validity of the inferences in (13a,b)-(15a,b). As such,
abstract objects may well exist. Nonetheless, some abstract objects
(e.g., Sherlock Holmes and Zeus) may be said "not to
exist" in the sense that nothing exemplifies the properties
which they encode.



Though Quine's (1948) well-known paper "On what there
is," raises serious ontological questions for intentional-object
theories, both Parsons and Zalta have provided answers to
Quine's queries, in their respective work. Nonetheless, to this
day, many contemporary philosophers have been reluctant to embrace
intentional-object theories for two related reasons. First of all,
they have been eager to avoid what they see as the heavy ontological
commitments incurred by intentional-object theories. Secondly, the
ontology of non-existent and abstract objects has seemed difficult to
square with the ontology of the contemporary natural sciences
according to which the world contains only concrete objects that exist
in space and time. (See Section 9 for further discussion.)



The theory of intentional objects, however, may derive support from
the following, arguably counterintuitive, consequences of
Frege's and Russell's views, respectively. Frege's
theory faces two problems. First (13a)-(15a) would appear to express
truths. But on Frege's view, they lack a truth-value, since they
involve singular terms devoid of reference and, according to Frege, if
part of a sentence lacks a reference, then the sentence itself fails
to have a truth-value (see section 4). Secondly, the inferences in
(13)-(15) appear to be valid. But on Frege's view, one cannot
validly infer (13b) from (13a) if (13a) has no truth-value. Similarly
for the other pair of sentences (14) and (15). Russell's view
faces two analogous problems. First, as noted above, (13a)-(15a)
appear to be true. But on Russell's analysis, proper names such
as "Zeus" in (13a) and "Sherlock Holmes" in
(15a) are abbreviated definite descriptions and, given his analysis of
definite descriptions, both (13a) and (15a) turn out to express false
existentially quantified propositions (see section 5). Secondly, if
(13a)-(15a) are indeed false, as Russell's view would have it,
then one cannot validly infer (13b)-(15b), respectively, from their
corresponding premisses. For a recent novel account of the distinction
between true and false thoughts about non-existent objects, cf. Crane
(2013) and for further discussion of the general topic of existence,
see the SEP entry on existence.


## 8. Is intensionality a criterion of intentionality?



Within the orthodox paradigm, an entirely different reaction to the
puzzles of intentional inexistence has been to try to clarify the
ontological difficulties by ascending to a higher semantic level that
can, as Willard Van Orman Quine (1960, 272) says, "carry the
discussion into a domain where both parties are better agreed on the
objects (viz., words)." Semantic ascent allows one to rise from
talk about things to talk about talk about things, i.e., words. In
contemporary analytic philosophy, Roderick Chisholm (1957, 298) was
the first to contemplate the formulation of "a working criterion
by means of which we can distinguish sentences that are intentional,
or are used intentionally, in a certain language from sentences that
are not." The idea is to examine sentences that report
intentionality rather than intentionality itself.



Intensionality (with an *s*) is non-extensionality. Two
features are characteristic of extensionality. First, if a linguistic
context is extensional, two coreferential terms can be substituted one
for the other *salva veritate* as illustrated by (16) and
(17):


16. Hesperus shines.
17. Phosphorus shines.



If (16) is true, so is (17). Secondly, the law of existential
generalization applies to either (16) or (17) to yield
'[?]*x*(*x* shines).' Not so with
intensionality. As illustrated by examples (3) and (4) repeated here,
the truth of (3) does not always entail the truth of (4):


3. Ava believes that Hesperus is shining.
4. Ava believes that Phosphorus is shining.



Nor can existential generalization always be validly applied to
sentences reporting beliefs, since from the fact that John believes
that angels have wings, it does not follow that there are things such
that John believes of them that they have wings.



Chisholm's criterion of intensionality is threefold. First, a
sentence reports an intentional phenomenon if it contains a singular
term that purports to refer to some object and it is such that neither
it nor its negation implies that the purported reference of the
singular term does or does not exist. The first criterion amounts to
the recognition that if a sentence containing a singular term reports
an intentional phenomenon, then it fails to satisfy the law of
existential generalization (from '*Fa*' infer
'[?]*xFx*'). Secondly, a true sentence reports
an intentional phenomenon if it contains a singular term
'*a*' and if replacement of
'*a*' by coreferential term
'*b*' results in transforming the true sentence
into a false sentence that differs only from the former in that
'*b*' replaces '*a*'. The second
criterion amounts to recognition that if a sentence containing a
singular term reports an intentional phenomenon, then it fails the
test of the substitutivity of coreferential terms *salva
veritate*. Finally, if a complex sentence containing an embedded
'that'-clause reports an intentional phenomenon, then
neither it nor its negation entail the truth of the proposition
expressed by the embedded 'that'-clause.



Chisholm (1957) argued that reports or descriptions of intentional or
psychological phenomena cannot be reduced to (or eliminated in favor
of) descriptions of behavior. The intensionality or non-extensionality
of reports of intentionality was taken to show that descriptions and
explanations of psychological phenomena cannot be described nor
explained in terms of a vocabulary describing non-intentional
phenomena. As Quine (1960, 220) put it, "there is no breaking
out of the intentional vocabulary by explaining its members in other
terms". Chisholm (1957) took this conclusion to show the
correctness of Brentano's third thesis that intentionality
*is* the mark of the mental.



The question can be decomposed into two questions. On the one hand,
acceptance of intensionality as the criterion of intentionality seems
to reflect the endorsement of a general linguistic view of
intentionality in the following sense: what matters to the mental
(i.e. non-linguistic) state reported are the properties of the
linguistic report. There are at least two reasons for scepticism about
the linguistic view of intentionality. On the other hand, there are
some specific reasons for questioning two of Chisholm's
criteria. I start with the latter. It seems hard to deny that states
of *knowledge* are states with intentionality. At least,
reports of knowledge states satisfy Chisholm's second
non-substitutivity criterion. From the fact that knowledge ascription
(18) is true, it does not follow that (19) is, even though
'Cicero' and 'Tully' are coreferential:


18. Tom knows that Cicero denounced Catiline.
19. Tom knows that Tully denounced Catiline.
20. Cicero denounced Catiline.



However, unlike belief reports, reports of knowledge are
*factive*: (18) could not be true unless (20) was true and
Cicero did in fact denounce Catiline. Thus, unlike belief reports,
reports of knowledge fail Chisholm's third criterion. Given that
(20) is extensional, it obeys the law of existential generalization.
If the truth of (20) follows from the truth of (18) and if (20)
satisfies the law of existential generalization, then so does (18). If
so, then knowledge reports also fail to satisfy Chisholm's first
criterion.



One way to deal with this objection might be to argue that knowledge
reports fail the test of existential generalization precisely because,
unlike belief states, states of knowledge fail to exhibit
Brentano's intentional inexistence: only beliefs, not states of
knowledge, can be directed towards states of affairs that fail to
obtain and towards non-existent entities. Alternatively, one might
make a distinction between states with a stronger and states with a
weaker intentionality. Reports of the former (like beliefs) satisfy
Chisholm's three criteria. Reports of the latter (like states of
knowledge) only fail the substitutivity test.



The problem with this strategy is that there are sentences that seem
to describe intentional relations and that, unlike knowledge reports,
are *not* intensional at all, for they pass the substitutivity
test. This is the case of sentences about what Fred Dretske (1969)
calls *nonepistemic* perception. If, when he was alive, someone
saw the French writer Romain Gary, then she *ipso facto* saw
Ajar, for Ajar was no other than Romain Gary. However, if she failed
to know that 'Ajar' was another name for Romain Gary,
while seeing Romain Gary, she may have failed to see *that* the
man in front of her was Ajar. A fortiori, in this nonepistemic sense,
one cannot see an individual unless there is an individual to be seen.
One possible response might be to bite the bullet and deny that
nonepistemic perception is an intentional state at all. If so, then,
as Zalta (1988, 13) notes, linguistic reports of intentional phenomena
do satisfy at least one of Chisholm's criteria of
intensionality.



If seeing is intentional, then not all reports of intentionality are
intensional. That not all reports of intentionality are intensional is
a problem for the linguistic view according to which intensionality is
the criterion of intentionality. A second problem is that
intensionality is also a feature of sentences that are about phenomena
other than intentionality. Sentences that involve or are about
modalities such as necessity, about natural laws, about causation all
exhibit intensionality. So, for example, the truth of (21) does not
entail the truth of (22) even though everything that happens to
exemplify property *Q* happens to exemplify property
*R*:


21. It is a natural law that all *P*s are *Q*.
22. It is a natural law that all *P*s are *R*.



But necessity, natural laws or causation do not, on the face of it,
exhibit what Brentano took to be the defining characteristics of
intentionality. So it seems as if the intensionality of the report of
a phenomenon is neither necessary nor sufficient for the
intentionality of the reported phenomenon. Arguably, 'P',
'Q' and 'R' in (21)-(22) are not singular
terms at all. If they are treated as such, then, even though they may
be true of the same set of individuals, they do not refer or express
one and the same property. Still, the point illustrated by nomicity is
that the intensionality of a linguistic report is not sufficient for
the intentionality of the reported phenomenon.


## 9. Can intentionality be naturalized?



As we saw in section 8, Quine (1960, 220), a leading critic of
intentional objects (in the sense of section 7), agrees with Chisholm
(1957) that the intentional vocabulary cannot be reduced to some
non-intentional vocabulary. Chisholm (1957) took this conclusion to
show the correctness of Brentano's third thesis that
intentionality *is* the mark of the mental. From the same
conclusion, Quine (1960, 221) presented an influential dilemma with
both epistemological and ontological implications. The first horn of
the dilemma is to accept the "indispensability of intentional
idioms and the importance of an autonomous science of intention"
and to reject a physicalist ontology. The second horn of the same
dilemma is to accept physicalism and renounce the
"baselessness" of the intentional idioms and the
"emptiness" of a science of intention. This dilemma has
been influential in contemporary philosophy of mind.



The common legacy of Chisholm (1957) and Quine (1960) is the
linguistic view of intentionality (accepted by e.g., Dennett 1969).
Whether intensionality is indeed the defining criterion of
intentionality, one can certainly question Brentano's thesis
that *only* mental phenomena exhibit intentionality by noticing
that some non-mental things exhibit something very much like
Brentano's intentional inexistence, namely sentences of natural
languages. Sentences of natural languages have meaning and by virtue
of having meaning, they can be, just like states of mind, directed
towards things other than themselves, some of which need not exist in
space and time. Sentences of natural languages, however, are
non-mental things.



One influential response to this objection to this part of
Brentano's third thesis has been to grant a second-rate, i.e., a
degraded and dependent, intentional status to sentences (see Haugeland
1981, Searle 1980, 1983, 1992, Fodor 1987). On this view, sentences of
natural languages have no intrinsic meaning of and by themselves. Nor
do utterances of sentences have an intrinsic content. Sentences of
natural languages would fail to have any meaning unless it was
conferred to them by people who use them to express their thoughts and
communicate them to others. Utterances borrow whatever
'derived' intentionality they have from the
'original' (or 'primitive') intentionality of
human beings with minds that use them for their purposes (see Dennett
1987 for dissent). If, as Jerry Fodor (1975, 1987, 1994, 1998, 2008)
has argued, there exists a "language of thought"
consisting of mental symbols with syntactic and semantic properties,
then possibly the semantic properties of mental symbols are the
primary bearers of 'original' intentionality. (See the
entry on the
 language of thought hypothesis.)



So the question is: does any non-mental thing exhibit
'original' intentionality? The question is made more
pressing by Quine's dilemma, according to which one must choose
between Brentano's third thesis and a physicalist ontology.
So-called 'eliminative materialists' (see Churchland 1989)
resolutely opt for the second horn of Quine's dilemma and deny
purely and simply the reality of human beliefs and desires. As a
consequence of their denial of the reality of beliefs and desires, the
eliminative materialists must face the challenge raised by the
existence of physical objects whose existence depends on the
intentions, beliefs and desires of their designers, i.e., human
artifacts. Others, like Daniel Dennett (1971, 1978, 1987, 2017), who
rejects any sharp distinction between original and derived
intentionality on the grounds that original intentionality itself is
the output of natural selection, take a so-called
'instrumentalist' position. On Dennett's view, the
intentional idiom fails to describe or explain any real phenomenon.
However, in the absence of detailed knowledge of the physical laws
that govern the behavior of a physical system, the intentional idiom
(the 'intentional stance' as Dennett calls it) is a useful
stance for predicting a system's behavior. Among philosophers
attracted to a physicalist ontology, few have accepted the outright
eliminativist materialist denial of the reality of beliefs and
desires. Nor have many of them found it easy to answer the puzzling
question raised by the instrumentalist position: how can the
intentional idiom make useful predictions if it fails to describe and
explain anything real?



A significant number of physicalist philosophers subscribe to the task
of reconciling the existence of intentionality with a physicalist
ontology (for a forceful exposition see Field 1978, 78-79). On
the assumption that intentionality is central to the mental, the task
is to show, in Dennett's (1969, 21) terms, that there is
*not* an "unbridgeable gulf between the mental and the
physical" or that one can subscribe to both physicalism and
intentional realism. Because intentional states are *of* or
*about* things other than themselves, for a state to have
intentionality is for it to have semantic properties. As Jerry Fodor
(1984) put it, the naturalistic worry of intentional realists who are
physicalists is that "the semantic proves permanently
recalcitrant to integration to the natural order". Given that on
a physicalist ontology, intentionality or semantic properties cannot
be "fundamental features of the world," the task is to
show "how an entirely physical system could nevertheless exhibit
intentional states" (Fodor, 1987). As Dretske (1981) puts it,
the task is to show how to "bake a mental cake using only
physical yeast and flour". Notice that Brentano's own view
that 'no physical phenomenon manifests' intentionality is
simply unacceptable to a physicalist. If physicalism is true, then
some physical things are also mental things. The question for a
physicalist is: does any non-mental thing manifest intentionality?



Clearly, one way to relieve the tension between physicalism and
intentional realism is to argue that intentionality can be, and in
fact is, exhibited by non-mental things. There have been several
proposals in analytic philosophy in the past twenty years to suggest
ways of accomplishing this program, which has been called 'the
naturalization of intentionality.' The common strategy is to
show that Brentano was wrong in claiming that only mental things can
exhibit intentionality. This strategy is related to the assumption
that intentional relations whose relata are concrete particulars
should have primacy over intentional relations whose relata are not
(see
 section 7).
 I shall illustrate two distinct proposals for implementing this
common goal.



One influential strategy for showing that non-mental things can
exhibit intentionality has been Fred Dretske's (1980, 1981,
1994) *information*-theoretic proposal that a device that
carries information does exhibit some degree of intentionality. The
view is an extension of Paul Grice's (1957) notion of
*natural meaning*: unlike the English word 'fire,'
which non-naturally means fire, smoke naturally means fire. The word
'fire' can be tokened in the absence of any fire either
for the purpose of expressing a thought about what to do if there was
one or perhaps to mislead somebody else into falsely thinking that
there is one. But there cannot be any smoke unless there is a fire. As
we shall see momentarily, it is a feature of both the original
intentionality of beliefs and the derived intentionality of utterances
that they can be misrepresentations.



In essence, the information-theoretic proposal is that device
*S* carries information about instantiations of property
*G* if and only if *S*'s being *F* is
nomically correlated with instantiations of *G*. If *S*
would not be *F* unless property *G* were instantiated,
then *S*'s being *F* carries information about, or
as Dretske likes to say, indicates *G*-ness. A fingerprint
carries information about the identity of the human being whose finger
was imprinted. Spots on a human face carry information about a
disease. The height of the column of mercury in a thermometer carries
information about the temperature. A gas-gauge on the dashboard of a
car carries information about the amount of fuel in the car tank. The
position of a needle in a galvanometer carries information about the
flow of electric current. A compass carries information about the
location of the North pole. In all such cases, a property of a
physical device nomically covaries with some physical property
instantiated in its environment (for critical discussion of the
informational program, see Kistler 2000, Loewer 1987, 1998 and Putnam
1986).



Now, insofar as it is not a *law* that polar bears live at the
North pole, even though they happen to live there, a compass will fail
to carry information about where polar bears happen to live in spite
of the fact that it does carry information about the North pole. If
so, then reports of what a compass indicates exhibit one of
Chisholm's features of intensionality, namely coextensive terms
are not freely substitutable *salva veritate* in such reports.
By contrast, if it is law that variations of temperature covary with
variations in atmospheric pressure, then by virtue of indicating the
temperature, the height of the column of mercury in a thermometer will
also indicate atmospheric pressure. If there is a law relating current
flow to voltage differences, then by indicating the former, a
galvanometer will indicate the latter. One can, however, believe and
even know that there is a current flow between two points without
believing, let alone knowing, that there is a voltage difference
between the two points, if one fails to know that it is a law that if
there is flow of electric current between two points, then there is a
voltage difference between these two points (see Jacob 1997 for
discussion).



So although reports of the information carried by such physical
devices exhibit some of the intensionality exhibited by reports of
intentional mental states, the intensionality exhibited by the latter
is clearly stronger than the intensionality exhibited by the former.
On the one hand, it is difficult to generate the strong intentionality
of mental states from the information-theoretic account of the weak
intentionality of non-mental things. On the other hand, given that the
information relation is the converse of a nomic correlation, it is
difficult for informational semantics to account for misrepresentation
as well as for the normativity of the contents of mental states. See
the entry on
 causal theories of mental content..



A second influential proposal for dealing with the difficulties left
pending by the information-theoretic approach and for showing that
some non-mental things can exhibit intentionality has been Ruth
Millikan's (1984, 1993, 2000, 2004) *teleosemantic*
approach. Millikan's teleosemantic approach rests on two basic
assumptions, the first of which is that (unlike a natural sign) an
intentional representation is a relatum in a three-place relation
involving two mechanisms: a producer of the representation and a
consumer, both of which are cooperative devices whose activities are
beneficial to both. Millikan's second assumption is that
Brentano's relation of intentional inexistence is exhibited by
biological functions. Given any sort of biological purpose or design,
it might fail to be fulfilled. For example, if it is the function or
purpose of a mammal's heart to pump blood, then a mammal's
heart ought to pump blood even though it might fail to do so. Notice,
however, that whereas biological organs have functions that may fail
to be fulfilled, they do not *ipso facto* exhibit
intentionality in Brentano's full sense: neither a heart nor a
stomach are *of* or *about* anything. Millikan's
claim, however, is not that having a function is sufficient for
aboutness, but that it is necessary. Arguably, a device cannot be
about or represent anything unless it can misrepresent what it is
about. Presumably, for a device to misrepresent what it is about is
for it to misfunction. But unless the device had some function, it
could simply not misfunction. If this is correct, then nothing could
be a representational system--nothing could have content or
intentionality--unless it had what Millikan (1984) calls a
'proper' function.



The relevant notion of a function here is the biological teleological,
not the dispositional one: the function of an organ is not what the
organ is disposed to do, but what it was selected to do (see Millikan
1984 and Neander 1995). Arguably, nothing can have a function unless
it results from some historical process of selection or other.
Selection processes are design processes. Most advocates of
teleosemantics accept the etiological account of functions according
to which the function of a device is a selected effect, i.e. an effect
produced by the device that explains the continued proliferation of
tokens of this type of device. Thus, according to
"teleosemantic" theories, design is the main source of
function, which in turn is the source of content or intentionality.
Such theories are called "teleosemantic" theories in
virtue of the connection between design or teleology and content. One
contentious issue is whether the teleological approach championed by
Millikan can be combined with informational semantics so that
*S* can be said to represent instances of property *F*
if and only if it is *S*'s function to carry information
about *F*. On the one hand, against this proposal, Millikan
(2004) has argued that the information carried by a sign depends on
its causes, not its effects: according to teleosemantics and the
etiological approach to functions, the function of a device is one of
its effects: it does not depend on its causes. On the other hand,
Millikan (2017) proposes to redefine the border between concepts and
percepts by deepening her semiotic approach to perception based on the
related twin notions of *unicepts* and *unitrackers*.
Neander (2017) and Shea (2018) have further explored the possibility
of combining informational semantics and a teleological approach. For
further discussion of teleosemantics, see the SEP entry on
teleological theories of mental content and the papers collected in
Ryder, Kinsbury and Williford (eds.)(2011).



Now, selection processes can be intentional or non-intentional.
Artifacts (including words and other symbols of natural languages)
derive their functions from some intentional process. While
psychological mechanisms (e.g., belief-forming mechanisms) derive
their proper functions from a *non*-intentional selection
process, particular belief states have derived proper functions. The
paradigmatic non-intentional process is the process of natural
selection by which Charles Darwin explained the phylogenetic evolution
of biological species: natural selection sorts organisms that survive.
But no intentional agent is responsible for the sorting. Millikan
(1984, 2004, 2005) has also extended her teleosemantic approach to the
contents of intentional conventional signs (i.e. linguistic symbols).
If this sort of teleosemantic proposal could be fully worked out, then
it would kill two birds with one stone. On the one hand, it would
point a way in which the intentionality of minds derives from the
intentionality of biological things (see Rowlands 1999 for
discussion). On the other hand, it would show that some of the
normativity of mental states is already exhibited by biological
functions (see Neander, 1995). Both questions are currently topics of
much discussion in the philosophy of mind. Many philosophers such as
Davidson (1980), Kripke (1982), McDowell (1994) and Putnam (1988,
1994), for example, have either expressed serious reservations about
the program or provided reasons for scepticism. For further
discussion, see the essays in MacDonald and Papineau (eds.) 2006, and
also the entries on
 teleological theories of mental content
 and
 teleological notions in biology.
 Subsequently Burge (2010) criticized attempts to naturalize
intentionality by appeal to the notion of biological function on the
grounds that it is, according to him, a deep mistake to identify
representational success (truth or accuracy) with fulfillment of
biological function and representational failure (falsity or
inaccuracy) with failure of biological function. Unlike
representational (or semantic) success or failure, fulfillment or
failure of a biological function is, according to Burge, practical
success or failure.


## 10. Is intentionality exhibited by all mental phenomena?



Perceptions, beliefs, desires and intentions and many other
"propositional attitudes" are mental states with
intentionality. They are about or represent objects and states of
affairs under a particular psychological mode or format. Perceptions,
beliefs, desires and intentions illustrate a basic duality of the
intentionality of the mental: the duality between mind-to-world and
world-to-mind directions of fit. In order to clarify this duality,
Elizabeth Anscombe (1957, 56) considers a mere "shopping
list". The list may either be used as a set of instructions (or
a blueprint) for action by a customer in a store or it can be used as
an inventory by a detective whose purpose is to draw a record of what
the customer is buying. In the former case, the list is not to be
revised in the light of what lies in the customer's grocery bag.
But in the latter case, it is. If a mismatch should occur between the
content of the grocery bag and the list used by the customer, then the
blame should be put on the customer, not on the list. In the case of a
mismatch between the content of the bag and the list drawn by the
detective, the detective should correct his list.



Building on Anscombe's insight, Searle (1983) argues that there
are two opposite "directions of fit" that either speech
acts or mental states can exemplify: just as the speech act of
assertion has a word-to-world direction of fit, beliefs and
perceptions have a mind-to-world direction of fit. It is the function
of an assertion to state a fact or an actual state of affairs.
Similarly, it is the function of a belief and a perception to match a
fact. Unlike assertions, orders have a world-to-word direction of fit.
Unlike beliefs and perceptions, desires and intentions have a
world-to-mind direction of fit. It is the function of an order to
represent a non-actual possible or impossible state of affairs.
Similarly, it is the function of a desire and an intention to
represent a non-actual possible or impossible state of affairs.



Now the following questions arise: are Brentano and the
phenomenological tradition right? Do all mental states exhibit
intentionality? Is intentionality a feature of every aspect of human
experience? Are all forms of consciousness consciousness *of*
something? Does every mental state possess one or the other direction
of fit? Do sensations (e.g., pains), feelings, emotions (e.g.,
depression) all exhibit intentionality? These questions are very
controversial in contemporary philosophy of mind. Before examining
various contradictory answers to these questions, a preliminary
question is relevant. Whether Brentano was right or not, why should we
want a mark or a criterion of the mental at all?



The question of why we should seek a criterion of the mental at all
has been made pressing by some recent remarks of the linguist Noam
Chomsky (2000, 75, 106), according to whom methodological naturalism
mandates that we use terms like 'mind' and
'mental' on a par with terms like 'chemical',
'optical' or 'electrical.' Since we do not
seek to determine the true criterion of the electrical or the mark of
the chemical, by naturalistic parity of reasoning, Chomsky argues, we
should no more seek a criterion of the mental. Whether we need
criteria respectively for the chemical and for the optical, it is a
genuine issue whether the English word 'mental' can
justifiably apply to things as diverse as e.g., a pain and the belief
that 5 is a prime number. As Richard Rorty (1979, 22) has put it,
"the attempt to hitch pains and beliefs together seems ad
hoc--they don't seem to have anything in common except our
refusal to call them 'physical'". His conclusion is
that the word 'mental' expresses no single property, let
alone a 'natural kind.' On Rorty's irrealist view,
the word 'mental' is just part of an academic
language-game with no scientific explanatory import.



Thus, Rorty's radical irrealist picture of the mind relies on
the observation that pains and arithmetical beliefs seem to have
nothing in common. Not many contemporary philosophers of mind would
accept Rorty's irrealist picture of the mind. But most do
recognize that if minds are real, then *two* problems arise:
the problem of intentionality and the problem of consciousness or
conscious phenomenal experience. Most would claim that a solution to
the problem of intentionality is not *ipso facto* a solution to
the problem of consciousness. Why is that so?



Human beings can experience the world in various ways by means of
several distinct sensory modalities (vision, audition, touch,
olfaction). They are also aware of parts of their bodies as when they
suffer pains. The problem of consciousness is often called "the
problem of *qualia*" because states with a strong
phenomenal character--like pains, visual or olfactory
sensations--are states that introspectively seem endowed with a
strong intrinsic subjective quality. The general problem of
consciousness is to explain, in Thomas Nagel's (1974) famous
phrase, "what it is like" to be a certain creature with a
phenomenal experience. What is the phenomenal character--the
phenomenology--of the various forms of human experience? Few if
any philosophers--physicalist or otherwise--are inclined to
assume that, unlike intentionality, phenomenal consciousness can be
exemplified by non-mental things. Not many would deny that, although
pains, visual sensations, olfactory sensations, auditive sensations
are very different experiences, nonetheless they all exhibit a common
property called "phenomenal consciousness". From both a
scientific and a physicalist perspective, the questions arise whether
phenomenal consciousness is physical and whether it can be explained
in physical terms, i.e., as a result of processes happening in the
brain.



As many philosophers are willing to recognize, the concept expressed
by the word 'consciousness' is much in need of
clarification. Three such clarifications are worth mentioning. Two of
them consist in a pair of distinctions drawn by David Rosenthal
(1986). One distinction is between creature consciousness and state
consciousness. The other distinction is between transitive and
intransitive consciousness. A creature can be said to be
'intransitively' conscious if she is alive and normally
responsive to ongoing stimuli. She stops being intransitively
conscious while in a dreamless sleep, if she is knocked out, drugged
or comatose. A creature can be said to be 'transitively'
conscious if she is conscious *of* things, properties and
relations in her environment. Whereas a creature can be both
intransitively conscious and transitively conscious of something, a
mental state can only be intransitively conscious. One important
aspect of the problem of consciousness is the problem of how to draw
the line between conscious and unconscious mental states. A third
clarification has been Ned Block's (1995) distinction between
access consciousness (or A-consciousness) and phenomenal consciousness
(or P-consciousness). Whereas a state is said to be A-conscious if it
is poised for free use in reasoning and for direct rational control of
action and speech (i.e. available or accessible to several cognitive
mechanisms), the P-consciousness of a state is what it is like to be
in that state (whether or not it has A-consciousness). In recent work,
Block (2007) has argued that much evidence from the cognitive
scientific investigation of the visual system corroborates his
distinction between P- and A-consciousness. For example, on his
interpretation, experiments on change blindness and also the
neuropsychological investigation of brain-lesioned human patients with
neglect show that attention and working memory are necessary parts of
A-consciousness, but not of P-consciousness. What makes a state
A-conscious is that its content is made available to various cognitive
systems (e.g., attention and memory). Furthermore, not unless a visual
stimulus is attended and stored in working memory can an individual
report having seen it. But Block (2007) takes the evidence to show
that an individual can be P-conscious of the content of an
unreportable stimulus, i.e. a stimulus whose content has not been
either attended or stored in working memory. For supporting arguments,
see Dretske (2004, 2007). Block's interpretation of the
cognitive scientific data has been criticized by scientific advocates
of the so-called "global neuronal workspace model" of
consciousness: see e.g., Dehaene et al. (2006) and Naccache and
Dehaene (2007), which is a commentary to Block (2007). The global
neuronal workspace model of consciousness nicely fits with
Dennett's (1991, 2005) position on intentionality and
consciousness (which he has himself dubbed the "fame (in the
brain) theory of consciousness." (For further discussion of
these issues, see the SEP entry on
 attention.)



On the one hand, the notion of transitive creature consciousness seems
like a close cousin to the notion of intentionality. On the other
hand, what makes a person's mental state A-conscious is that the
person may have access to it. Presumably, a person may have conscious
access to one of her A-conscious mental states in virtue of having
some other mental state (e.g., a thought or belief) directed to it. So
having states with intentionality seems like a condition for any
mental state to be A-conscious. It follows that if the problem of
consciousness is to be clearly distinguished from the problem of
intentionality, the key question is that of explaining how a mental
state can be P-conscious.



Many philosophers do not accept Brentano's third thesis that
intentionality is the mark of all mental states. They do not reject
Brentano's second thesis on the grounds that intentionality can
be exhibited by some non-mental things. They reject it because, like
Block (1996) and Peacocke (1983), they subscribe to a view that can be
called 'anti-intentionalism,' according to which a
person's conscious mental state has a phenomenal character that
cannot be accounted either by its own intentionality (if it has any)
or by the intentionality of some other of his or her mental states.
Nor do they embrace Rorty's irrealist attitude towards the
mental. Some of the philosophers, who fall under the label
'anti-intentionalism,' may accept the thesis that
intentionality and the mental happen to coincide. But since they claim
that intentionality in turn derives from phenomenal consciousness,
they are not quite faithful to the spirit of Brentano's thesis
that intentionality is the constitutive feature of the mental.



The anti-intentionalists, who reject both Rorty's irrealism and
Brentano's thesis that intentionality is the true mark of the
mental, can be divided into two groups. Some, like Ned Block (1995,
1996), would accept a *dual* view according to which mental
states fall into a division between intentional states and phenomenal
states. As we shall see momentarily, this division is denied by the
intentionalists. In between the intentionalists and the phenomenal
realists, who accept the dual view, lies the intermediate view of
philosophers such as Colin McGinn (1989), Sydney Shoemaker (1996) and
Charles Siewert (1998), who see an intimate connection between
intentional and phenomenal states.



Other anti-intentionalists, like John Searle (1990, 1992) and Galen
Strawson (1994), go one step further and reject both Brentano's
thesis and the dual view of the mind. They hold consciousness to be
the true criterion of the mental. Arguably, as noted above, they might
accept the thesis that intentionality coincides with the mental, but
they hold the view that intentionality derives from consciousness. On
the one hand, Strawson (1994) clearly holds phenomenal consciousness
to be the true criterion of the mental. On the other hand, Searle
(1992) embraces what he calls "the Connection principle,"
according to which unless a mental state is available to
consciousness, it does not qualify as genuinely mental. As a result,
Searle (1992) seems to endorse the view that availability to
consciousness is the criterion of the mental. Now, the view that
availability to consciousness is the true criterion of the mental
entails that states and processes that are investigated by cognitive
science and that are unavailable to consciousness will fail to qualify
as genuine mental states. This view has been vigorously disputed by
Chomsky (2000). On the natural assumption that beliefs are
paradigmatic mental states, the view that phenomenal consciousness is
the true criterion of the mental further entails that there is
something it is like to have such a propositional attitude as
believing that 5 is a prime number--a consequence some find
doubtful. If there was nothing it is like to believe that 5 is a prime
number, then, according to the view that phenomenal consciousness is
the criterion of the mental, many propositional attitudes would fail
to qualify as genuine mental states. However, much recent work in the
philosophy of mind has been recently devoted to the defense of
so-called "cognitive phenomenology," according to which there is
something it is like to believe that e.g., 5 is a prime number. See
the SEP entry on consciousness and the papers collected in Bayne and
Montague (eds.) (2011).



Many of the philosophers who accept a version of Brentano's
thesis that all mental states exhibit intentionality try to show that
the mysteries of phenomenal consciousness can either be explained away
(i.e., dissolved) or that phenomenal consciousness derives from
intentionality. Daniel Dennett (1988, 1991, 2001) has been the most
consistent advocate of the view that the distinction between
phenomenal consciousness and access consciousness has been overrated
and that *qualia* ought to be 'quined,' i.e.,
resolutely denied and dispensed with.



So-called "intentionalists" are philosophers who think
that phenomenal consciousness can really be explained by
intentionality because they think that phenomenal states are
intentional states. On the intentionalist account, the phenomenal
qualities of an experience are the properties that objects are
represented as having in the experience. Some intentionalists, like
Fred Dretske (1995) and Michael Tye (1995), think that whereas
thoughts and propositional attitudes are mental representations with
conceptual content, *qualia* or conscious experiences are
mental representations with *nonconceptual content* (about
which see Dretske 1981, Peacocke 1992, 2001 and the essays in Crane
1992). On their view, to have phenomenal features is to have a certain
sort of nonconceptual content. On Tye's (1995) view, for
example, pains are mental representations of bodily parts and the
phenomenal experience of a pain is the nonconceptual content of the
bodily representation. Other intentionalists such as Elizabeth
Anscombe (1965) and especially John McDowell (1994), who are skeptical
of the distinction between conceptual and nonconceptual content, will
appeal to other criteria, e.g., functional role, to account for
phenomenal states (see the SEP entry on Nonconceptual mental content).
For example, McDowell (1994) argues that the phenomenal content of
experience can be explained in terms of a suitable notion of
demonstrative conceptual content.



There are currently two outstanding issues facing an intentionalist
approach to phenomenal experiences. The first is whether the
intentionalist account can be extended to the phenomenal character of
all sensory and bodily experiences. This is at present an open
question (cf. Crane, 2007). The second issue is whether the
nonconceptual content of perceptual experiences can be objective in
representing and referring to particular objects, or whether only
conceptual thoughts can be objective and represent or refer to
particular objects. On the one hand, Evans (1982), Dretske (1981,
1995) and Peacocke (1992) assume that propositional thought or
conceptual content is required to achieve reference to particulars. On
the other hand, Burge (2010) has offered powerful considerations
(mostly derived from perceptual psychology) in favor of the
objectivity of purely perceptual representations. On Burge's
view, perceptual representations are both sensory and objective
representations of the environment. Their nonconceptual content need
not be supplemented by intellectualized (higher-order) representations
of what makes a representation objective in order to provide objective
representations of particulars.



Finally, according to David Rosenthal's "higher-order
thought" theory of consciousness, what makes a person's
mental state conscious is that the person is conscious of it by virtue
of having formed a higher-order thought (or HOT) about it.
Furthermore, the phenomenal character of a person's sensory
experience--what it is like for the person to be in that
state--arises from the fact that the person has formed a HOT
about it. The problem with the HOT theory of phenomenal consciousness
is that the theory entails that creatures who, like non-human animals
and human babies, lack the ability to form HOTs will be deprived of
phenomenal consciousness--a consequence many will find
implausible (cf. Rosenthal, 1986, 2005). For further discussion, see
the SEP entries on
 consciousness and intentionality
 and
 higher-order theories of consciousness.