## 1. Versions of the Coherence Theory of Truth




The coherence theory of truth has several versions. These versions
differ on two major issues. Different versions of the theory give
different accounts of the coherence relation. Different varieties of
the theory also give various accounts of the set (or sets) of
propositions with which true propositions cohere. (Such
a set will be called a *specified set*.) 




According to some early versions of the coherence theory, the
coherence relation is simply consistency. On this view, to say that a
proposition coheres with a specified set of propositions is to say that
the proposition is consistent with the set. This account of coherence
is unsatisfactory for the following reason. Consider two propositions
which do not belong to a specified set. These propositions could both
be consistent with a specified set and yet be inconsistent with each
other. If coherence is consistency, the coherence theorist would have
to claim that both propositions are true, but this is impossible.




A more plausible version of the coherence theory states that the
coherence relation is some form of entailment. Entailment can be
understood here as strict logical entailment, or entailment in some
looser sense. According to this version, a proposition coheres with a
set of propositions if and only if it is entailed by members of the
set. Another more plausible version of the theory, held for example in
Bradley (1914), is that coherence is mutual explanatory support
between propositions.




The second point on which coherence theorists (coherentists, for
short) differ is the constitution of the specified set of propositions.
Coherentists generally agree that the specified set consists of
propositions believed or held to be true. They differ on the questions
of who believes the propositions and when. At one extreme, coherence
theorists can hold that the specified set of propositions is the
largest consistent set of propositions currently believed by actual
people. For such a version of the theory, see Young (1995). According
to a moderate position, the specified set consists of those
propositions which will be believed when people like us (with finite
cognitive capacities) have reached some limit of inquiry. For such a
coherence theory, see Putnam (1981). At the other extreme, coherence
theorists can maintain that the specified set contains the propositions
which would be believed by an omniscient being. Some idealists seem to
accept this account of the specified set.




If the specified set is a set actually believed, or even a set which
would be believed by people like us at some limit of inquiry,
coherentism involves the rejection of realism about truth. Realism
about truth involves acceptance of the principle of bivalence
(according to which every proposition is either true or false) and the
principle of transcendence (which says that a proposition may be true
even though it cannot be known to be true). Coherentists who do not
believe that the specified set is the set of propositions believed by
an omniscient being are committed to rejection of the principle of
bivalence since it is not the case that for every proposition either it
or a contrary proposition coheres with the specified set. They reject
the principle of transcendence since, if a proposition coheres with a
set of beliefs, it can be known to cohere with the set.


## 2. Arguments for Coherence Theories of Truth




Two principal lines of argument have led philosophers to adopt a
coherence theory of truth. Early advocates of coherence theories were
persuaded by reflection on metaphysical questions. More recently,
epistemological and semantic considerations have been the basis for
coherence theories. 


### 2.1 The Metaphysical Route to Coherentism




Early versions of the coherence theory were associated with
idealism. Walker (1989) attributes coherentism to Spinoza, Kant, Fichte
and Hegel. Certainly a coherence theory was adopted by a number of
British Idealists in the last years of the nineteenth century and the
first decades of the twentieth. See, for example, Bradley
(1914).




Idealists are led to a coherence theory of truth by their
metaphysical position. Advocates of the correspondence theory believe
that a belief is (at least most of the time) ontologically distinct
from the objective conditions which make the belief true. Idealists do
not believe that there is an ontological distinction between beliefs
and what makes beliefs true. From the idealists' perspective, reality
is something like a collection of beliefs. Consequently, a belief
cannot be true because it corresponds to something which is not a
belief. Instead, the truth of a belief can only consist in its
coherence with other beliefs. A coherence theory of truth which results
from idealism usually leads to the view that truth comes in degrees. A
belief is true to the degree that it coheres with other beliefs.




Since idealists do not recognize an ontological distinction between
beliefs and what makes them true, distinguishing between versions of
the coherence theory of truth adopted by idealists and an identity
theory of truth can be difficult. The article on Bradley in this
Encyclopedia (Candlish 2006) argues that Bradley had an identity
theory, not a coherence theory.




In recent years metaphysical arguments for coherentism have found
few advocates. This is due to the fact that idealism is not widely
held.


### 2.2 Epistemological Routes to Coherentism




Blanshard (1939, ch. XXVI) argues that a coherence theory of
justification leads to a coherence theory of truth. His argument runs
as follows. Someone might hold that coherence with a set of beliefs is
the test of truth but that truth consists in correspondence to
objective facts. If, however, truth consists in correspondence to
objective facts, coherence with a set of beliefs will not be a test of
truth. This is the case since there is no guarantee that a perfectly
coherent set of beliefs matches objective reality. Since coherence with
a set of beliefs is a test of truth, truth cannot consist in
correspondence.




Blanshard's argument has been criticised by, for example, Rescher
(1973). Blanshard's argument depends on the claim that coherence with a
set of beliefs is the test of truth. Understood in one sense, this
claim is plausible enough. Blanshard, however, has to understand this
claim in a very strong sense: coherence with a set of beliefs is an
infallible test of truth. If coherence with a set of beliefs is simply
a good but fallible test of truth, as Rescher suggests, the argument
fails. The "falling apart" of truth and justification to which
Blanshard refers is to be expected if truth is only a fallible test of
truth.




Another epistemological argument for coherentism is based on the
view that we cannot "get outside" our set of beliefs and compare
propositions to objective facts. A version of this argument was
advanced by some logical positivists including Hempel (1935) and
Neurath (1983). This argument, like Blanshard's, depends on a coherence
theory of justification. The argument infers from such a theory that we
can only know that a proposition coheres with a set of beliefs. We can
never know that a proposition corresponds to reality.




This argument is subject to at least two criticisms. For a start, it
depends on a coherence theory of justification, and is vulnerable to
any objections to this theory. More importantly, a coherence theory of
truth does not follow from the premisses. We cannot infer from the fact
that a proposition cannot be known to correspond to reality that it
does not correspond to reality. Even if correspondence theorists admit
that we can only know which propositions cohere with our beliefs, they
can still hold that truth consists in correspondence. If correspondence
theorists adopt this position, they accept that there may be truths
which cannot be known. Alternatively, they can argue, as does Davidson
(1986), that the coherence of a proposition with a set of beliefs is a
good indication that the proposition corresponds to objective facts and
that we can know that propositions correspond.




Coherence theorists need to argue that propositions cannot
correspond to objective facts, not merely that they cannot be known to
correspond. In order to do this, the foregoing argument for coherentism
must be supplemented. One way to supplement the argument would be to
argue as follows. As noted above, the correspondence and coherence
theories have differing views about the nature of truth conditions. One
way to decide which account of truth conditions is correct is to pay
attention to the process by which propositions are assigned truth
conditions. Coherence theorists can argue that the truth conditions of
a proposition are the conditions under which speakers make a practice
of asserting it. Coherentists can then maintain that speakers can only
make a practice of asserting a proposition under conditions the
speakers are able to recognise as justifying the proposition. Now the
(supposed) inability of speakers to "get outside" of their beliefs is
significant. Coherentists can argue that the only conditions speakers
can recognise as justifying a proposition are the conditions under
which it coheres with their beliefs. When the speakers make a practice
of asserting the proposition under these conditions, they become the
proposition's truth conditions. For an argument of this sort see Young
(1995).


## 3. Criticisms of Coherence Theories of Truth




Any coherence theory of truth faces two principal challenges. The first
may be called the specification objection. The second is the
transcendence objection. 


### 3.1 The Specification Objection




According to the specification objection, coherence theorists have
no way to identify the specified set of propositions without
contradicting their position. This objection originates in Russell
(1907). Opponents of the coherence theory can argue as follows. The
proposition (1) "Jane Austen was hanged for murder" coheres
with some set of propositions. (2) "Jane Austen died in her
bed" coheres with another set of propositions. No one supposes
that the first of these propositions is true, in spite of the fact that
it coheres with a set of propositions. The specification objection
charges that coherence theorists have no grounds for saying that (1) is
false and (2) true.




Some responses to the specification problem are unsuccessful. One
could say that we have grounds for saying that (1) is false and (2) is
true because the latter coheres with propositions which correspond to
the facts. Coherentists cannot, however, adopt this response without
contradicting their position. Sometimes coherence theorists maintain
that the specified system is the most comprehensive system, but this
is not the basis of a successful response to the specification
problem. Coherentists can only, unless they are to compromise their
position, define comprehensiveness in terms of the size of a
system. Coherentists cannot, for example, talk about the most
comprehensive system composed of propositions which correspond to
reality. There is no reason, however, why two or more systems cannot
be equally large. Other criteria of the specified system, to which
coherentists frequently appeal, are similarly unable to solve the
specification problem. These criteria include simplicity, empirical
adequacy and others. Again, there seems to be no reason why two or
more systems cannot equally meet these criteria.




Although some responses to the Russell's version of the
specification objection are unsuccessful, it is unable to refute the
coherence theory. Coherentists do not believe that the truth of a
proposition consists in coherence with any arbitrarily chosen set of
propositions. Rather, they hold that truth consists in coherence with a
set of beliefs, or with a set of propositions held to be true. No one
actually believes the set of propositions with which (1) coheres.
Coherence theorists conclude that they can hold that (1) is false
without contradicting themselves.




A more sophisticated version of the specification objection has been
advanced by Walker (1989); for a discussion, see Wright (1995). Walker
argues as follows. In responding to Russell's version of the
specification objection, coherentists claim that some set of
propositions, call it *S*, is believed. They are committed to
the truth of (3) "*S* is believed." The question of
what it is for (3) to be true then arises. Coherence theorists might
answer this question by saying that "'*S* is
believed' is believed" is true. If they give this answer,
they are apparently off on an infinite regress, and they will never
say what it is for a proposition to be true. Their plight is worsened
by the fact that arbitrarily chosen sets of propositions can include
propositions about what is believed. So, for example, there will be a
set which contains "Jane Austen was hanged for murder,"
"'Jane Austen was hanged for murder' is
believed," and so on. The only way to stop the regress seems to
be to say that the truth conditions of (3) consist in the objective
fact *S* is believed. If, however, coherence theorists adopt
this position, they seem to contradict their own position by accepting
that the truth conditions of some proposition consist in facts, not in
propositions in a set of beliefs.




There is some doubt about whether Walker's version of the
specification objection succeeds. Coherence theorists can reply to
Walker by saying that nothing in their position is inconsistent with
the view that there is a set of propositions which is
believed. Even though this objective fact obtains, the truth conditions
of propositions, including propositions about which sets of
propositions are believed, are the conditions under which they cohere
with a set of propositions. For a defence of the coherence theory against
Walker's version of the specification objection, see Young (2001).




A coherence theory of truth gives rise to a regress, but it is not a
vicious regress and the correspondence theory faces a similar regress.
If we say that *p* is true if and only if it coheres with a
specified set of propositions, we may be asked about the truth
conditions of "*p* coheres with a specified set."
Plainly, this is the start of a regress, but not one to worry
about. It is just what one would expect, given that the coherence
theory states that it gives an account of the truth conditions of all
propositions. The correspondence theory faces a similar benign
regress. The correspondence theory states that a proposition is true
if and only if it corresponds to certain objective conditions. The
proposition "*p* corresponds to certain objective
conditions" is also true if and only if it corresponds to
certain objective conditions, and so on.


### 3.2 The Transcendence Objection




The transcendence objection charges that a coherence theory of truth
is unable to account for the fact that some propositions are true which
cohere with no set of beliefs. According to this objection, truth
transcends any set of beliefs. Someone might argue, for example, that
the proposition "Jane Austen wrote ten sentences on November
17th, 1807" is either true or false. If it is false, some other
proposition about how many sentences Austen wrote that day is true. No
proposition, however, about precisely how many sentences Austen wrote
coheres with any set of beliefs and we may safely assume that none will
ever cohere with a set of beliefs. Opponents of the coherence theory
will conclude that there is at least one true proposition which does
not cohere with any set of beliefs.




Some versions of the coherence theory are immune to the
transcendence objection. A version which holds that truth is coherence
with the beliefs of an omniscient being is proof against the objection.
Every truth coheres with the set of beliefs of an omniscient being. All
other versions of the theory, however, have to cope with the objection,
including the view that truth is coherence with a set of propositions
believed at the limit of inquiry. Even at the limit of inquiry, finite
creatures will not be able to decide every question, and truth may
transcend what coheres with their beliefs.




Coherence theorists can defend their position against the
transcendence objection by maintaining that the objection begs the
question. Those who present the objection assume, generally without
argument, that it is possible that some proposition be true even though
it does not cohere with any set of beliefs. This is precisely what
coherence theorists deny. Coherence theorists have arguments for
believing that truth cannot transcend what coheres with some set of
beliefs. Their opponents need to take issue with these arguments rather
than simply assert that truth can transcend what coheres with a
specified system.


### 3.3 The Logic Objection




Russell (1912) presented a third classic objection to the coherence
theory of truth. According to this objection, any talk about coherence
presupposes the truth of the laws of logic. For example, Russell
argues, to say that two propositions cohere with each other is to
presuppose the truth of the law of non-contradiction. In this case,
coherentism has no account of the truth of law of
non-contradiction. If, however, the coherence theorist holds that the
truth of the law of non-contradiction depends on its coherence with a
system of beliefs, and it were supposed to be false, then propositions
cannot cohere or fail to cohere. In this case, the coherence theory of
truth completely breaks down since propositions cannot cohere with
each other.



Coherentists have a plausible response to this objection. They may
hold that the law of non-contradiction, like any other truth, is true
because it coheres with a system of beliefs. In particular, the law of
non-contradiction is supported by the belief that, for example,
communication and reasoning would be impossible unless every system of
beliefs contains something like law of non-contradiction (and the
belief that communication and reasoning are possible). It is true
that, as Russell says, if the law is supposed not to cohere with a
system of beliefs, then propositions can neither cohere nor fail to
cohere. However, coherence theorists may hold, they do not suppose the
law of non-contradiction to be false. On the contrary, they are likely
to hold that any coherent set of beliefs must include the law of
non-contradiction or a similar law.


## 4. New Objections to Coherentism



 Paul Thagard is the author of the first of two recent new arguments
 against the coherence theory. Thagard states his argument as
 follows:



> if there is a world independent of representations of it,
> as historical evidence suggests, then the aim of representation should
> be to describe the world, not just to relate to other
> representations. My argument does not refute the coherence theory, but
> shows that it implausibly gives minds too large a place in
> constituting truth. (Thagard 2007: 29-30)




Thagard's argument seems to be that if there is a mind-independent
world, then our representations are representations of the world. (He
says representations "should be" of the world, but the
argument is invalid with the addition of the auxiliary verb.) The
world existed before humans and our representations, including our
propositional representations. (So history and, Thagard would likely
say, our best science tells us.) Therefore, representations,
including propositional representations, are representations of a
mind-independent world. The second sentence of the passage just quoted
suggests that the only way that coherentists can reject this argument
is to adopt some sort of idealism. That is, they can only reject the
minor premiss of the argument as reconstructed. Otherwise they are
committed to saying that propositions represent the world and, Thagard
seems to suggest, this is to say that propositions have the sort of
truth-conditions posited by a correspondence theory. So the coherence
theory is false.




In reply to this argument, coherentists can deny that
propositions are representations of a mind-independent world. To say
that a proposition is true is to say that it is supported by a
specified system of propositions. So, the coherentist can say,
propositions are representations of systems of beliefs, not
representations of a mind-independent world. To assert a proposition
is to assert that it is entailed by a system of beliefs. The
coherentist holds that even if there is a mind-independent world, it
does not follow that the "the point" of representations is
to represent this world. If coherentists have been led to their
position by an epistemological route, they believe that we cannot
"get outside" our system of beliefs. If we cannot get
outside of our system of beliefs, then it is hard to see how we can be
said to represent a mind-independent reality.




Colin McGinn has proposed the other new objection to coherentism. He
argues (McGinn 2002: 195) that coherence theorists are committed to
idealism. Like Thagard, he takes idealism to be obviously false, so
the argument is a reductio. McGinn's argument runs as
follows. Coherentists are committed to the view that, for example,
'Snow falls from the sky' is true iff the belief that snow
falls from the sky coheres with other beliefs. Now it follows from
this and the redundancy biconditional (*p* is true
iff *p*) that snow falls from the sky iff the belief that snow
falls from the sky coheres with other beliefs. It appears then that
the coherence theorist is committed to the view that snow could not
fall from the sky unless the belief that snow falls from the sky
coheres with other beliefs. From this it follows that how things are
depends on what is believed about them. This seems strange to McGinn
since he thinks, reasonably, that snow could fall from the sky even if
there were no beliefs about snow, or anything else. The linking of how
things are and how they are believed to be leads McGinn to say that
coherentists are committed to idealism, this being the view that how
things are is mind-dependent.




Coherentists have a response to this objection. McGinn's argument
works because he takes it that the redundancy biconditional means
something like "*p* is true
because *p*". Only if redundancy biconditionals are
understood in this way does McGinn's argument go through. McGinn needs
to be talking about what makes "Snow falls from the sky"
true for his reductio to work. Otherwise, coherentists who reject his
argument cannot be charged with idealism. He assumes, in a way that a
coherent theorist can regard as question-begging, that the truth-maker
of the sentence in question is an objective way the world
is. Coherentists deny that any sentences are made true by objective
conditions. In particular, they hold that the falling of snow from the
sky does not make "Snow falls from the sky"
true. Coherentists hold that it, like any other sentence, is true
because it coheres with a system of beliefs. So coherentists appear to
have a plausible defence against McGinn's objection.