## 1. Life and career




|  |  |
| --- | --- |
| 1729 | born September 6 in Dessau, Anhalt-Dessau, Germany |
| 1743 | follows Rabbi Frankel to Berlin and studies with the Maimonides
scholar, Israel Samoscz |
| 1754 | becomes accountant for firm of silk manufacturer, Isaak
Bernhard; begins lifelong friendship with Gotthold Ephraim
Lessing |
| 1755 | publishes anonymously "Philosophical Dialogues,"
"On Sentiments," and (with Lessing) *Pope, a
Metaphysician!* |
| 1756 | publishes anonymously *Thoughts on Probability* and a
translation with critical evaluation of Rousseau's second
*Discours* |
| 1757 | publishes anonymously "Considerations on the Sources and
the Connections of Fine Arts and Sciences" in *Library of
Fine Sciences and Fine Arts* which he co-edits with Lessing and
Friedrich Nicolai |
| 1758 | publishes anonymously "Considerations of the Sublime and
the Naive in the Fine Sciences" in *Library of Fine
Sciences and Fine Arts* |
| 1760 | composes Hebrew commentary on Moses Maimonides'
*Logical Terms* |
| 1761 | publishes *Philosophical Writings*, containing his
previously published essays together with a new essay, "Rhapsody
or Additions to the Letters on the Sentiments" |
| 1762 | marries Fromet Gugenheim |
| 1763 | awarded prize by the Royal Academy of Sciences for "On
Evidence in Metaphysical Sciences" (published a year later) |
| 1767 | publishes *Phaedo: or On the Immortality of the Soul, in
Three Dialogues* |
| 1768 | completes Hebrew commentary on *Ecclesiastes*; assumes
co-management of Bernhard firm with Bernhard's widow |
| 1769 | publishes *Letter to Lavater* in response to
Lavater's challenge to refute or embrace Charles Bonnet's
arguments for Christianity |
| 1771 | publishes second edition of *Philosophical Writings*;
onset of illness; denial of membership in Royal Academy |
| 1777 | publishes third edition of *Philosophical Writings*;
intervenes successfully in Dresden to prevent expulsion of needy
members of Jewish community |
| 1780 | publishes translation of *Genesis* |
| 1781 | publishes translation of *Exodus* |
| 1783 | publishes *Jerusalem or On Religious Power and Judaism*
and translations of *Pentateuch* and *Psalms* |
| 1784 | publishes "On the Question: What does 'to
enlighten' mean?" |
| 1785 | publishes *Morning Hours or Lectures on the Existence of
God* |
| 1786 | dies January 4; final publication *To the Friends of Lessing:
An Appendix to Mr. Jacobi's Correspondence on the Doctrine of
Spinoza* appears January 26 |


## 2. Metaphysics and epistemology



Mendelssohn's "On Evidence in Metaphysical Sciences"
(the so-called *Prize Essay*) garnered first prize in the
contest staged by the Royal Prussian Academy of Sciences on the
question of whether metaphysical truths are able to have the same sort
of evidence as mathematical truths. (An essay by Immanuel Kant came in
second place; for a detailed comparison and contrast of the two
"prize essays," see Guyer 2020, 27-72.) In
Mendelssohn's essay, published in 1763, he argues that
metaphysics pursues its subject matter by applying the same method
that mathematics does: conceptual analysis. As he puts it, "The
analysis of concepts is for the understanding nothing more than what
the magnifying glass is for sight" (*Philosophical
Writings*, p. 258). But Mendelssohn then proceeds to differentiate
the kinds of evidence in mathematics and in metaphysics in the
following way. Like calculus, but unlike geometry, metaphysics works
with concepts that are no less certain than those of geometry, but
lack the transparency and imaginative resources available to the
geometer's concepts. The difference between mathematics and
metaphysics lies in the difference in the content of the concepts,
namely, the difference between quantity and quality. At the same time,
there is a basic harmony between the two disciplines since quantity
and quality are both intrinsic characteristics of finite things and
neither quantity nor quality exists without the other (for review of
Mendelssohn's and Kant's theories of mathematics, see
Callanan 2014).



Mendelssohn acknowledges that, despite the fact that the method is the
same and the content in each case (mathematics and metaphysics) is an
intrinsic character of things, progress in metaphysics has lagged far
behind that in mathematics. He suggests three "objective"
reasons for this lag: first, metaphysics' greater reliance upon
arbitrary signs (signs that do not essentially coincide with what is
signified); second, the holistic content of metaphysics (no quality
can be defined without an adequate insight into the others); and
third, metaphysics' need to establish the actual existence of
what corresponds to the analyzed concepts. Thus, for Mendelssohn,
mathematical truths need not suppose more than the appearances of
things as long as a distinction is maintained between constant and
inconstant appearances or, equivalently, between appearances that have
their basis in the intrinsic, essential constitution of our senses and
those that do not (e.g., those due to sickness or a faulty
perspective). "Thus, even in the system of a doubter or an
idealist, the value of not only pure, theoretical mathematics but even
practical and applied mathematics remains, and it retains its
undeniable certainty" (*Philosophical Writings*, p. 268).
Metaphysics, by contrast, requires a resolution of the problem of
idealism.



Twenty-five years after the *Prize Essay*, Mendelssohn
continues to struggle with the issue of idealism in *Morning
Hours*, his final metaphysical work. Although he espouses a theism
that is compatible with a realist position (what he dubs
"dualism" as opposed to idealism, materialism, and
skepticism), he appears to be moving toward a position that straddles
an idealist/non-idealist divide. He views inquiry into something
"extra-conceptual" as tantamount to "inquiring about
a concept that is actually no concept and therefore something
contradictory is supposed" (*Morning Hours*, p.
42/*Gesammelte Schriften*, 3/2, pp. 60f). A further tilt in the
direction of idealism is apparent in his rejection of the traditional
definition of truth as an agreement of things with thoughts, on the
ground that the copy (the thought) cannot be compared with the
original (the thing). Since thoughts can be compared with one another,
he turns to them for a determination of truth, though it is not clear
how this move can avoid idealism. At the same time, however, he
distinguishes *truths that are certain* (consisting in the
agreement of thoughts with themselves) from *actual truths*,
determined by adherence to principles of induction and analogy in
addition to the principle of noncontradiction. The latter truths are
truths about facts outside us or about a causal connection, though
they are relative to certain factors: the number of sensations of a
single sort that agree with one another, the number of different sorts
of sensations that concur, and the number of times our assessment
agrees with those of others, of other species, and of even
"higher entities" (*Morning Hours*, pp. 6f, 37ff,
41/*Gesammelte Schriften*, 3/2, pp. 15f, 54f, 59; for review of
Mendelssohn's epistemology in the undeservedly neglected first
part of Morning Hours, see Dahlstrom 2018b and, more fully, Guyer
2020, 123-140). Echoing Descartes, Mendelssohn maintains that
demonstration of God's existence is necessary to certify the
actual existence of things outside us.



This ambivalence can perhaps be traced to the mature
Mendelssohn's growing suspicions that the entire issue
separating idealists and those supporting contrasting positions is
misbegotten, a product of linguistic confusion (see the discussion of
Mendelssohn's views on language below). "I fear that, in
the end, the famous debate among materialists, idealists, and dualists
amounts to a merely verbal dispute that is more a matter for the
linguist than for the speculative philosopher" (*Morning
Hours*, p. 42 (translation slightly altered)/*Gesammelte
Schriften*, 3/2, p. 61). Mention has already been made of
Mendelssohn's view in the *Prize Essay* that
metaphysics' necessary reliance upon artificial signs is one
reason why its difficulties are more intractable than those of
mathematics. In 1785, in *Morning Hours*, he goes further:
"You know how much I am inclined to explain all the
controversies of the philosophical schools as merely verbal disputes
or at least as originally deriving from verbal disputes"
(*Morning Hours*, p. 75/*Gesammelte Schriften*, 3/2, p.
104; for commentary, see Dahlstrom 2011). In keeping with these
advancing suspicions about the origin and the efficacy of the issue
over idealism and dualism (realism), Mendelssohn eventually comes to
assign reason a mediating role in disputes between common sense and
speculation. Common sense is usually but not invariably right, he
contends, and hence reason's task is to present a defense of
speculation when it departs from common sense. For valuable discussion
of Mendelssohn's approach to common sense, see Franks 2011. (The
appeal to reason to mediate and, if necessary, to rein in speculation
also plays a significant role in Mendelssohn's account of a
"refined" or "purified" pantheism in
*Morning Hours*. On this point, see below "9. Controversy
with Jacobi over Lessing's alleged pantheism"). As for the
impact of Mendelssohn's approach to idealism in *Morning
Hours*, many scholars concur that Kant's Refutation of
Idealism directly takes it up. However, at least one scholar contends
that Kant does so by accepting Mendelssohn's approach (Munk
2011b) while others argue, albeit for contrasting reasons, that he
does so in order to refute Mendelssohn's position (Dyck 2011;
Guyer 2018a; see, too, Guyer's contrast of Mendelssohn's
more empirically-bent "modest epistemology" with
Kant's more rationalist-inspired "transcendental
idealism," in Guyer 2020, 167-201.)


## 3. Rational psychology



In *Phaedo or On the Immortality of the Soul*, loosely modeled
on Plato's dialogue, Mendelssohn combines a paean to Socrates
with an elaboration of the dreadful personal, moral, and political
implications if a person's life is her "highest
good." A best-seller of its time, running through three
editions, this "classic of rational psychology," as
Dilthey put it, also contains an argument for the simplicity and
immortality of the human soul, explicitly singled out for criticism by
Kant in the second edition of the *Critique of Pure Reason*
(for review of Kant's and Mendelssohn's different
approaches to the question of immortality, see Guyer 2020, 142-166).
Mendelssohn supports the notion that the soul is simple and thus
indestructible by noting that certain features of the soul, namely,
the unifying character of consciousness and the identity of
self-consciousness, cannot be derived from anything composite, whether
those composite parts be capable or not of thinking. "We would
be able neither to remember nor to reflect nor to compare nor to
think, indeed, we would not even be the person who we were a moment
ago, if our concepts were divided among many and were not to be
encountered somewhere together, combined in the most precise ways they
can. We must, therefore, assume at least one substance that combines
all concepts of the component parts.... There is, therefore, in
our body at least one sole substance that is not extended, not
composed, but instead is simple, has a power of representing things
[*Vorstellungskraft*], and unites all our concepts, desires,
and inclinations in itself" (*Phadon* (2007), pp.
119f (translation slightly altered)/*Gesammelte Schriften*,
3/1, pp. 96f). As for the human soul's fate after death,
Mendelssohn appeals to divine goodness and providence, which perhaps
explains why, following the publication of the *Phaedo*, he
finds himself needing to revisit the proofs for God's existence.
Playing an important role in Mendelssohn's development of his
views of the human vocation and human immortality in the years prior
to the composition of the *Phaedo* is a 1764-65 debate
with Thomas Abbt. On the topic of Thomas Abbt's role in this
regard, his correspondence with Mendelssohn, and Herder's
critical reaction to Mendelssohn's views, see Pollok 2017 and
Pollok 2018b. For an insightful study of Mendelssohn's
anthropology more generally, see Pollok 2010.


## 4. Natural Theology



From the beginning of his career to the end, Mendelssohn consistently
upheld the demonstrability of God's existence. However, not all
arguments were equally compelling in his view. In the *Prize
Essay* he contends that probable arguments for God's
existence based upon beauty, order, and design are more eloquent and
edifying but less certain and convincing than strict demonstrations.
Similarly, in *Morning Hours*, he cites the argument that the
external senses' testimony to an external world is unthinkable
without a necessary, extra-worldly being, but adds that this sort of
argument would hardly convince an idealist, sceptic, or solipsist.
There are, however, at least two ways in which, according to
Mendelssohn, God's existence can be established with certainty.
The first way is through application of the principle of sufficient
reason to the certain existence of contingent things. The inner
testimony of one's own cogito attests to the existence of
something contingent. Since the sufficient reason for the existence of
contingent things must "indirectly" be a necessary being,
a necessary being exists. Hence, Mendelssohn sums up this argument by
saying: "I am, therefore there is a God."
(*Philosophical Writings*, p. 289; *Gesammelte
Schriften*, 3/2, pp. 78, 83f).



Mendelssohn's second way of proving God's existence is
based upon consideration of the idea of God together with the
conditions of nonexistence. If something does not exist, then it is
either impossible or merely possible. To say that something
nonexistent is impossible is to say that its intrinsic properties are
contradictory, e.g., a square circle. To say that something
nonexistent is possible is to say both that its intrinsic properties
are insufficient to determine that it exists and that it is contingent
upon extrinsic factors that do not obtain. If God does not exist, then
it is either because the idea of God is impossible or because it is
merely possible, i.e., contingent. Since contingency entails
dependency and independence is greater than dependence, it would
contradict the essence of a perfect being for that being to be
contingent. Hence, the idea of a perfect being cannot be the idea of
something merely possible. But the idea of a perfect being also does
not contain determinations that must be affirmed and denied at the
same time; in other words, the idea is not impossible. In this way
Mendelssohn concludes that God exists from the consideration that the
idea of God cannot be the idea of something nonexistent. While we can
conceive finite, contingent, entities as nonexistent, we cannot
conceive as nonexistent an infinite, necessary entity, namely, an
entity that combines all affirmative features and properties to the
highest degree. "It can either not be thought at all or not be
thought otherwise than with the predicate of actual existence"
(*Morning Hours*, p. 113/*Gesammelte Schriften*, 3/2, p.
154). In this connection, it deserves mention that Mendelssohn rejects
as quibbling the objection that existence is not a predicate. A
concept of existence, he maintains, emerges in all of us in a similar
way as we search for what is common to what we do and undergo, thereby
enjoying a universality that is not further analyzable. Thus,
Mendelssohn will allow that existence is not a predicate, that it is
different from all features and properties of things, and, hence,
cannot be merely added to the list of properties of the most perfect
entity. Nevertheless, whether existence is the "position"
of all properties of a thing or something inexplicable, Mendelssohn
stands by his claim that we can only think something contingent
without it. As he sums up the inference: "A God is thinkable,
therefore a God is also actually on hand [*vorhanden*]"
(*Morning Hours*, p. 56 (translation slightly
altered)/*Gesammelte Schriften*, 3/2, p. 78).



Towards the end of *Morning Hours* Mendelssohn introduces a
further proof for God's existence, based upon our certainty of
"the imperfection of our self-knowledge" (*Morning
Hours*, p. 107/*Gesammelte Schriften* 3/2, p. 147). We have
certain knowledge, Mendelssohn contends, not only of ourselves but
also of the limited scope of this knowledge. "I am not merely
what I distinctly know of myself or, what amounts to the same, there
is more to my existence than I might consciously observe of myself;
and even what I know of myself is in and for itself capable of far
greater development, greater distinctness, and greater completeness
than I am able to give it" (*Morning Hours*, p.
103/*Gesammelte Schriften* 3/2, p. 141). From the limitations
of our knowledge of ourselves (or, for that matter, of anything actual
existing) together with the less plausible assumption that "that
everything actual must be thought to be actual by some thinking
being," Mendelssohn infers that there is "an infinite
intellect" that does represent everything to itself (*Morning
Hours*, pp. 103f/*Gesammelte Schriften* 3/2, pp. 141ff; for
a detailed comparison of Kant's favorable, pre-critical and
unfavorable, critical views of proofs of God's existence with
Mendelssohn's early and late championing of certain proofs, see
Guyer 2020, 75-141; see, too, Rovira 2017.)


## 5. Ethics



Mendelssohn's ethics is a form of perfectionism, resembling the
rationalist perfectionism of Christian Wolff's ethics but also
significantly departing from it in ways that echo Mendelssohn's
appreciation of aesthetic and affective dimensions of moral life. In
the fourth and final part of his Prize Essay, Mendelssohn investigates
the extent of evidence in the foundational principles of ethics
(*Anfangsgrunde der Sittenlehre*) and, in particular, how
it compares to evidence ("the certainty and
comprehensibility") of geometry's basic principles. He
introduces the discussion with the observation that when someone
undertakes the right sort of action, that person "tacitly"
makes the following "rational inference," a moral
syllogism in the form of a modus ponens:



> 
> 
> Major premise: "Where the property A is encountered, my duty
> requires me to do B."
> 
> 
> 
> Minor premise: "The present case has the property A."
> 
> 
> 



The major premise is a "maxim, a general rule of living,"
assumed at some other point and remembered on the present occasion.
The minor premise is based "upon an exact observation of the
present circumstances and on the conviction that they fully agree with
requisite properties A." As in mathematics, the doctrine of
morals divides into two parts, the theoretical (instructional) and the
practical (applied), where the former conveys the general rules of
living that serve as the major premises and the latter their
application in a particular case. Mendelssohn submits that it is not
difficult to prove "with geometric rigor and trenchancy"
the general principles of ethics, i.e., the rational principles that
prescribe what to do and to leave undone. Nothing is clearer or more
compelling, he observes, than Marcus Aurelius' conclusion that
these principles follow from what is common to us as rational
creatures. Because human beings have a common power of making value
judgments (*Beurtheilungskraft*), all their judgments about
good and evil rest upon the same ground, diverging from one another
only to the degree that their insight does. There are accordingly
"universal ground-rules" (what Mendelssohn also dubs
"laws of nature") according to which human beings are
supposed to decide what to do and leave undone. Moving freely between
the singular and the plural in this regard, Mendelssohn refers without
qualification to both "this universal law of nature" and
"laws of nature," but this looseness can probably be
attributed to the fact that he entertains three ways of proving and
thus articulating "the first law of nature."



The first proof is based upon observation. To determine these
universal laws of nature, one need only observe what human beings do
and leave undone, their various inclinations and passions, and single
out what they all aim for. What all the desires and wishes, passions
and inclinations have in common is the pursuit of "the
preservation or betterment of our inner or outer condition or that of
another creature." Both those who are virtuous and those who are
ridden with vices aim at perfection, true or illusory, a perfection
understood as the preservation or betterment of their inner or outer
state or that of others. From this universal pursuit the first law of
nature flows, namely, "make your inner and outer state and that
of others, in proper proportion, as perfect as you can." Duties
to oneself, others, and to God can be derived from this first law.
(The argument is short on details, to be sure, supposing as it does a
universality and essentialness not afforded without further ado by
observation alone.)



The second proof establishes the same basic law but does so "a
priori" on the basis of the "mere definition" of an
entity with free will. The choices made by such an entity are based
upon what it finds pleasing, namely, "the perfection, beauty,
and order" that it perceives or believes that it perceives in
the preferred objects. With their unmistakably aesthetic accent, these
qualities serve as "motivating grounds"
(*Bewegungsgrunde*) to act or refrain from acting. Without
being physically coercive, these motivating grounds entail an
"obligatoriness" or "moral necessity," since
no free spirit could enjoy the opposite of them. This proof has been
recently challenged in at least two, complementary ways (Klemme 293).
First, if a free, rational person necessarily chooses to act in
accordance with her knowledge of good and evil, how can she be
required to perfect herself? Second, why is the law normative and not
merely descriptive? These are significant objections but they arguably
suppose positions that neither Mendelssohn, the proponent of common
sense, nor Mendelssohn, the metaphysician, can countenance. By
underscoring the imperfection but also the corrigibility of reasonable
people, common sense insures the meaningfulness of the injunction to
self-perfection. From a metaphysical description of the basis
(motivations, ends) of a rational choice, normative constraints follow
for making precisely those sorts of choices.



The third proof of this universal law of nature is based upon its
agreement with the final purpose of creation. From the assumption of a
creator of the world who acts with wisest of intentions, it follows
that promotion of the perfection of the creation must be God's
will. To be sure, might never makes right and Mendelssohn accordingly
stresses that law is a consequence not of divine power but of the
right of a divine will. Nonetheless, from (i) the fact that God can
only want what is best and (ii) the fact that "a right is
nothing other than a moral capacity to do what conforms to the rule of
perfection," it follows that God possesses the right to
prescribe to his creation laws that are necessarily rules of its
perfection. This third proof arguably represents a further departure
from Wolff who rejects the equivalence of the natural law with a
divine command. For Wolff, only someone lacking reason has need of
motivations other than natural obligatoriness (Klemme 295f).



Summing up these three proofs, Mendelssohn lists three basic maxims
that lead to the same conclusion. Whether we (1) consider what is
common to all human inclinations, (2) recognize ourselves as entities
endowed with free wills, or (3) acknowledge that we are God's
creation, "all three maxims lead to the common conclusion:
perfect yourself and others."



Mendelssohn employs the expression "right of nature"
(*Naturrecht*) to designate the sum of the laws of natural
right resulting from the application of these rational principles to
individual cases. Given this one universal law of nature, the concepts
of moral philosophy are sufficiently connected with one another to
make up a theoretical system and it is possible to develop "all
our duties, rights, and obligations" from that natural law. The
result is a moral philosophy as certain as metaphysics, namely, a
"science of the qualities [*Beschaffenheiten*] of an
entity with free will." At the same time, he contends that the
derivation, not only of the universal natural law, but also of various
maxims from it ("Love virtue," "control your
passions") is as certain as any geometric proof. Yet, unlike
geometry, ethics is about human action and this science is, moreover,
"erected on the grounds of metaphysics," in particular,
the metaphysical doctrines of God, the world, and the human soul.
Hence, evidence in moral philosophy is necessarily even more difficult
to obtain than in metaphysics. While the foundational principles of
ethics can be proven with the same certainty (*Gewissheit*) as
those of geometry, it is not on the same level with respect to its
ability to be comprehended (*Fasslichkeit*). Unlike geometry,
ethics supposes the comprehension of those metaphysical truths.



As for applied ethics, it is in the same position as any other
practical science in that its degree of certainty is dependent upon
contingent and unknown circumstances as well as upon actions'
effects that cannot be foreseen with certainty. The minor premise of
the practical syllogism, determining what we should do in practice,
i.e., in the case before us, runs through all levels of probability.
Then, too, there is the possibility that the obligatoriness of some
higher-level duty stands in the way of the application of a
lower-level duty but that, given the situation, this fact escapes
"the sharpest attention." Indeed, what mortal, Mendelssohn
asks, can be certain that his action is the best that he can do? In
most cases, "conscience and a fortunate sense for the truth
(*bon-sens*)" must stand in for reason. Like taste in
regard to beauty and its opposite, conscience and a sense for truth
are capacities, developed over time, of correctly distinguishing good
and evil, true and false respectively without the benefit of extensive
reflection and on the basis of inferences that are less than clear.
Despite the fogginess of its inferences, "this inner
feeling," this sense for the good and the true, acts on us
according to universal principles that, through constant practice,
have been incorporated into our temperament and accordingly influence
our desires far more than the clearest rational inferences that may
convince but fail to stir us. Coupled with the acknowledgment of the
lack of the appropriate distinct concepts for the particular
application, this recourse to conscience as a feeling suggests a
further sharp break with the rationalism of Wolff and his followers
(Klemme 298f).



By way of introducing the last segment of this discussion of evidence
in ethics, Mendelssohn distinguishes theoretical and practical forms
of approval. While it is impossible to doubt what is a matter of
intellectual conviction, it is possible for us to act contrary to an
obligation that we are convinced of. So, too, some truths are
intellectually convincing but do not move us, whereas other, less
certain truths do so, producing "lively and efficacious"
cognition, passing over into the faculty of desire, and even
motivating decisions. The familiar reason for this discrepancy in the
efficaciousness of truths is, Mendelssohn, submits, the recalcitrance
of inclinations to reason. Approval of a truth becomes practical if
the rational principles either gain the upper hand over inclinations
or put them to its advantage. Mendelssohn identifies ethics'
four means of securing the agreement of reason and desire: (1)
increasing the number of motivations, (2) practice and habit, (3)
adding pleasant sensations (for which art and literature are
particularly useful), and (4) examples that have been observed or can
be intuited (e.g., history, Aesop's fables).


## 6. Aesthetics



Mendelssohn makes singular contributions to the development of the
newly developing discipline of aesthetics in 18th century Germany (for
overviews of German aesthetics and Mendelssohn's place in it at
the time, see Beiser 2009, Pollok 2010, Madonna 2011, and Guyer 2014).
In *On the Main Principles of the Fine Arts and Sciences*,
Mendelssohn sets out from the assumption that the human spirit has
learned to imitate beauty, "the self-empowered mistress of all
our sentiments," in works of art. He then proceeds to ask what
the arts have in common or, in other words, what beauty is.
Batteux's thesis that art consists in the imitation of nature
merely defers the question or, better, requires its revision to the
effect that we ask what the beauties of nature and of art have in
common. After rejecting Hutcheson's appeal to an aesthetic sense
as a deus ex machina that forecloses inquiry, Mendelssohn contends
that the common feature is a sensuously perfect representation (a
contention that can be traced back to Sulzer and Baumgarten).
"Sensuous" in this connection stands not simply for the
fact that an object is sensed by the external senses, but also for the
fact that an entire array of an object's features is perceived
all at once. Unlike the distinct representation of a triangle whereby
the intellect distinguishes parts and aspects of the triangle from one
another, a sensuous representation is clear but indistinct, that is to
say, to have a sensuous representation is to perceive something
without intellectually distinguishing its parts or aspects. But we can
sensuously perceive an order or harmony to those aspects without
intellectually distinguishing them. Beauty or the perfect sensuous
representation -- whether in nature or in art -- accordingly
pertains to forms, orders, harmonies, and "indeed, everything
capable of being represented to the senses as a perfection"
(*Philosophical Writings*, p. 172). On this definition of art,
what is represented can be ugly or repugnant as long as the
representation is sensuously perfect (though Mendelssohn does address,
as discussed below, the mixed sentiment that accrues when the object
represented is unpleasant). From these considerations, Mendelssohn
derives two necessary conditions of fine art and letters: faithfulness
of the representation ("imitation") and, far more
importantly, the artistry, even "genius," involved. In
this connection, he argues that, as far as individual beauties in
nature are concerned, they are inferior to the beauties produced by
arts. In *On the Main Principles* Mendelssohn also establishes
the general distinction between fine arts and fine science along the
lines of the difference between natural and artificial signs. Whereas
the "fine arts" (*beaux arts*) -- music,
dance, painting, sculpture, and architecture -- predominantly
work with natural signs, the "fine sciences" (*belles
lettres*) -- poetry and rhetoric -- typically employ
artificial signs. The distinction is hardly ironclad, however, and
Mendelssohn ends *On the Main Principles* with a discussion of
ways the arts may borrow from one another (e.g., allegorical painting)
or combine (e.g., opera).



At one point in the dialogue *On Sentiments*
(Mendelssohn's second publication but first publication on
aesthetic matters), one of the protagonists differentiates three sorts
of pleasure: sensuous, beautiful, and intellectual (a differentiation
which approximates respectively the three sorts of perceptions
elaborated by Leibniz and Wolff, among others, namely, confused,
clear, and distinct). In this context, Mendelssohn explains how beauty
affords a distinctive pleasure precisely as the unity of the
multiplicity of things taken in by the senses (a view subsequently
iterated, as we have seen, in *On the Main Principles*).
Unaddressed by this differentiation of pleasures, however, are the
so-called "mixed sentiments" that we seem to experience
sometimes in viewing what is otherwise painful, terrifying, or, at any
rate, does not exhibit the harmony or order typical of beauty. At
first (namely, in *On Sentiments*) Mendelssohn thought that the
problem could still be handled by identifying some perfection in the
object -- e.g., the skillfulness of the gladiator, the virtue of
the tragic figure -- as the source of the pleasure that we feel.
Six years later, in *Rhapsody or additions to the Letter on
sentiments*, he revises his explanation of these mixed sentiments
by noting that each individual representation has a subjective and an
objective component (for a valuable account of Mendelssohn's
developing conception of mixed sentiments, see Pollok 2018a).
Subjectively or "as a determination of the soul," the
representation can affirm some perfection in the soul and thus be
pleasing, even though objectively or "as a picture of the
object," we might find it repugnant. Tragedy is more complicated
since the sympathy that we feel for the tragic figure is based upon
both objective and subjective perfections (i.e., in him or her and us)
as well as upon objective imperfection, the pain and injustice that
befall him or her.



Mendelssohn gives another twist to his interpretation of "mixed
sentiments" in the *Rhapsody* and then later in "On
the Sublime and the Naive in the Fine Sciences."
Experiences of the sheer immensities of things -- "the
unfathomable world of the sea, a far-reaching plain, the innumerable
legions of stars, the eternity of time, every height and depth that
exhausts us" (*Philosophical Writings*, p. 144) --
sometimes make us tremble, but we still find them alluring. It is
gratifying to experience them, though they confirm an imperfection as
well as a perfection in us. In "On the Sublime,"
Mendelssohn further distinguishes beauty as something bounded from
immensity as something unbounded. He then distinguishes extended from
non-extended (intensive) immensity. The sea's unfathomableness
would be an example of extended immensity in nature; uniform
repetition of temporal intervals in music would be an example of an
attempt to represent the experience of an extended immensity in art.
But Mendelssohn seems to be more interested in the non-extended or
intensive immensities. "Power, genius, virtue have their
unextended immensity that likewise arouses a spine-tingling sentiment
but has the advantage of not ending, through tedious uniformity, in
satiation and even disgust, as generally happens in the case of the
extended immensity" (*Philosophical Writings*, p. 194).
Mendelssohn then introduces the category of sublimity for the perfect
representation of such intensive immensity, a representation that
produces awe precisely because it passes beyond our customary
expectations. For an insightful treatment of Mendelssohn's view
of mixed sentiments as "a complex account of the multiple
sources of aesthetic responses to art," see Guyer 2011.



There is one last aspect of Mendelssohn's aesthetics that
deserves mention, not least for its bearing on subsequent developments
in aesthetics. It has already been noted that the pleasures of beauty
and sublimity are not to be identified as purely sensuous or purely
intellectual pleasures. In keeping with this differentiation,
Mendelssohn differentiates the sort of approval involved in aesthetic
experiences from knowledge or desire, though he insists that aesthetic
feelings of pleasure can, nonetheless, serve "as the transition
(*Uebergang*) as it were from knowing to desiring"
(*Gesammelte Schriften*, 3/2, pp. 61f; *Philosophical
Writings*, pp. 169, 307-310). In his adoption of three
distinct capacities of the mind and in his appraisal of the aesthetic
dimension as providing a bridge between matters of truth and falsity
(capacities of knowing) and matters of good and evil (capacities of
desiring), Mendelssohn plainly anticipates central aspects of
Kant's mature, critical philosophy. A further, though less
precise similarity also deserves mention, namely, the likeness between
Kant's conception of the disinterested character of experience
of the beautiful and Mendelssohn's conception of the experience
as something affording us a pleasure that is neither simply sensuous
or intellectual. "We consider the beauty of nature and art with
pleasure and satisfaction, without the slightest movement of desire.
Instead, it appears to be a particular mark of beauty that it is
considered with tranquil satisfaction; that it pleases if we also do
not possess it and we are still far removed from demanding to possess
it" (*Gesammelte Schriften*, 3/2, p. 61;
*Philosophical Writings*, pp. 34-51). For a more detailed
review of the robust affinities of Kant's aesthetics with
Mendelssohn's (despite Kant's rejection of perfectionism
in aesthetics) together with a discussion of certain advantages of
Mendelssohn's aesthetics in contrast to Kant's, see Guyer
2018b. More recently, while indicating how, prima facie appearances to
the contrary notwithstanding, "Kant's core aesthetic
experience seems deeply Mendelssohnian," Guyer nonetheless
identifies significant differences between their aesthetics. These
differences include Mendelssohn's appreciation of the broader
range of properties - not least sensory qualities -
that enter into aesthetic experience and his recognition of "the
centrality of the expression of emotion in the experience of
art." Guyer suggests two reasons for these differences:
Mendelssohn's lack of concern for the question of the universal
validity of aesthetic judgment (presumably imperiled in Kant's
view by introducing a role for sentiment) and the central role that
Mendelssohn assigns to emotion in moral motivation; see Guyer 2020,
245-255.


## 7. Political theory



In *Jerusalem, or on Religious Power and Judaism* Mendelssohn
distinguishes church and state in order to demonstrate the salutary
harmony between them and thus the need for tolerance. In the first
part of the essay he accordingly argues that neither the state nor
religion can legitimately coerce human conscience and, in the second
part, he maintains that this argument against "religious
power" is supported by Judaism. The second point was no less
controversial than the first, especially since many Jewish elders and
rabbis maintained a right to excommunicate. But Mendelssohn counters
-- apparently erroneously -- that the practice is not
inherent in "ancient, original Judaism" but rather
borrowed in the course of time from Christianity.



Far from separating temporal and spiritual concerns to distinguish
state and church (as Locke did), Mendelssohn insists that "our
welfare in this life is ... one and the same as [our] eternal
felicity in the future" (*Jerusalem* (1983), p. 39). Nor
does he base the distinction between church and state on the
difference between convictions and actions. "Both state and
church have as their object actions as well as convictions, the former
insofar as they are based on the relations between man and nature, the
latter insofar as they are based on the relations between nature and
God" (*Jerusalem* (1983), p. 56f). As far as convictions
are concerned, neither church nor state can coerce; "for
here," as noted earlier, "the state has no other means of
acting effectively than the church does. Both must teach, instruct,
encourage, motivate" (*Jerusalem* (1983), p. 61). What
contributes mightily to their potential for mutual reinforcement is
the fact that there is also no difference in the make-up of the
convictions and duties themselves. The only difference between church
and state in the matter of convictions is their ultimate sanction.
Thus, the moral philosopher will arrive at the same system of duties
as the person who sees them as expressions of the divine; religion
"only gives those same duties and obligations a more exalted
*sanction*" (*Jerusalem* (1983), p. 58). Matters
are different when it comes to actions where the state can and must
coerce, namely, when society's size and complexity "make
it impossible to govern by convictions alone, [and] the state will
have to resort to public measures, coercive laws, punishments of
crime, and rewards of merit" (*Jerusalem* (1983), p. 43).
Herein lies for Mendelssohn the basic difference between state and
church: civil society has, as the product of a social contract, the
right to coercion, religious society has no such right. "The
state has *physical power* and uses it when necessary; the
power of religion is *love* and *beneficence*"
(*Jerusalem* (1983), p. 45).



Insofar as Mendelssohn's argument for religious tolerance has a
religious premise, i.e., insofar as duties to others are founded upon
the relation to God ("the more exalted sanction," cited
above), it is less advantageous, it has been argued, than Kant's
argument that rests simply on the innate right to freedom (Guyer
2018c). An analogous challenge from a Kantian perspective concerns the
implications of Mendelssohn's defense of speculation as a source
of reason's authority for his view of history.
Mendelssohn's rejection of the idea of moral progress in history
and Kant's endorsement of the idea coincide, it is argued (Sweet
2018), precisely with the contrast between Mendelssohn's
acceptance of an authority external to reason and Kant's
insistence upon a self-legislating reason. For discussion of
Kant's criticisms of Mendelssohn's
"abderitism" (non-progressivism), see Guyer 2020,
321-337.



In *Jerusalem*, Mendelssohn argues that Judaism is, at bottom,
a natural religion, containing no revealed truths not available to
unaided reason. Occasionally, as Allan Arkush points out
(*Jerusalem* (1983), p. 20), he speaks more guardedly,
restricting this claim to the "essentials" of Judaism.
Even with such qualifications, however, it is apparent that
Mendelssohn approaches Judaism and its history with a more or less
Deist view that the original, ancient faith confirmed nothing more
than rational truths. Nonetheless, he combines this rationalist
approach with a conception of revelation that underscores the
distinctiveness of Judaism and secures Jewish believers their destiny
as God's chosen people. For, while the Sinaitic revelation
contains no supernatural truths, it does prescribe a way of life, the
practice of which stands to benefit all mankind. (The interpretation
of revelation strictly as legislation and not as adding to the store
of truths is very likely borrowed, with qualifications, from Spinoza).
"Judaism boasts of no *exclusive* revelation of eternal
truths that are indispensable to salvation, of no revealed religion in
the sense in which that term is usually understood. Revealed
*religion* is one thing, revealed *legislation*,
another" (*Jerusalem* (1983), p. 97). This gloss hardly
does justice to *Jerusalem* and its significance; for further
discussion, see, for example, Arkush 1994, Berghahn 2001, Gottlieb
2011, McQuillan 2014, Rosenstock 2010, Pecina 2016, Sacks 2017, and
Guyer 2020.


## 8. Language



Mendelssohn finds linguistic considerations at the very heart of
traditional philosophical questions. As noted above ("2.
Metaphysics and epistemology"), in the *Prize Essay* he
regards metaphysics' greater reliance upon arbitrary signs as
one reason for its slow progress (relative to that in mathematics) and
in *Morning Hours* he indicates his inclination to regard
disputes over idealism as purely verbal. Joining these remarks about
the import of language for philosophy are two main treatments of
language, one at the beginning, the other at the end of his career. At
the outset he critically addresses Rousseau's views on the
origin of language in the context of the Berlin Academy's essay
competitions on language (see *Sendschreiben an den Herrn Magister
Lessing in Leipzig*, the appendix to the translation of
Rousseau's *Discours sur les origins de
l'inegalite* (1756), and Mendelssohn's
review of Michaelis' prize-winning essay (1759) in *Briefe,
die neueste Literatur betreffend* and "Uber die
Sprache" (circa 1759)). Michaelis won the Academy's prize
for answering its question: "Quelle est l'influence
reciproque des opinions d'un people sur le langage et du
langage sur les opinions?"). Mendelssohn takes issue both with
Rousseau's attempt to explain the origin of human language on
the basis of a description of the natural condition that human beings
share with other animals and with his neglect of any consideration of
the providential character of the development of language
(*Gesammelte Schriften* 6/2, p. 27). In these early writings on
language, Mendelssohn emphasizes the interdependence of language and
its development with the development of innate, divinely-endowed
capacities. These capacities include not only reason as the ability to
grasp conceptual connections and employ arbitrary signs
(*Gesammelte Schriften* 6/2, pp. 9f), but also -- in
tandem with the development of rational capacities -- the
capacity for compassionate interaction in familial and social
settings. Thus, on the one hand, the recurrence of auditory, visual,
and gesticular phenomena enables reason to signify phenomena bearing
no resemblance to them and, indeed, to do so in a way decidedly
different from how other animals instinctively employ natural,
imitative signs (*Gesammelte Schriften* 6/2, p. 10). In this
manner Mendelssohn underlines the interdependence of reason and
language, understood as the use of arbitrary signs. On the other hand,
language develops within a process that is social as well as cognitive
and the starting point for the investigation of its origins is the
family rather than the individual. Borrowing from Condillac and
challenging Rousseau's view of language as primarily a tool for
socialization, Mendelssohn writes: "The drive to social life is
equally innate in human beings and leads immediately to the occasion
for exercising the capacity for language"(*Gesammelte
Schriften* 6/2, p. 8).



In *Jerusalem*, toward the end of his career, Mendelssohn
returns to the subject of language in the context of articulating the
sense in which Judaism is -- for good reasons -- a religion
of the spoken rather than the written word, relying on an a living
tradition to transmit and interpret divine legislation. In this
context Mendelssohn again emphasizes the fundamentally social
character of language in the context of the performance of rituals,
while calling attention to both the feebleness of ostensive definition
and the fraught prospects for maintaining the same reference for words
over time. In the course of arguing that human reason does not need
supernatural revelation in order to recognize the eternal truths
indispensable to its happiness, Mendelssohn notes that Judaism relies,
not upon written phrases or formulations that are "established
forever, immutable," but instead upon a "living tradition
passed on by oral instruction," capable of keeping pace with
changing times and circumstances (*Jerusalem* (1983), p. 97f,
102f (translation slightly altered)/*Gesammelte Schriften* 8,
pp. 160, 168). Judaism is thus for Mendelssohn primarily a religion of
the spoken word precisely as a means of maintaining its relevance to
real life in changing, historical contexts and maintaining the
personal bonds and Jewish identity among its members (see Sacks
2017).



Mendelssohn adds a further reason for insisting that Judaism is a
religion of the spoken word, precisely as a supernatural legislation
rather than a revealed religion. The constant attention paid to the
written word not only can isolate human beings from one another and
speculation from practice, but also can induce a kind of idolatry.
Frozen in time, the written word can become an idol itself, obscuring
the distinction between itself and what it is meant to signify (see
Freudenthal (2012), pp. 105-134).



In this connection Mendelssohn conjectures that written language
emerged in the course of the development of visible signs, beginning
with a form of synecdoche where a concrete object reawakens the
thought of a particular characteristic, e.g., a dog as a sign of
fidelity. While the move from these objects to images of them and
ultimately to hieroglyphics seems natural enough, Mendelssohn muses
that the transition from hieroglyphics to a written alphabet
"required a leap," far beyond ordinary human powers
(*Jerusalem* (1983), p. 108/*Gesammelte Schriften* 8, p.
174). Nonetheless, it is written language's hieroglyphic origins
that Mendelssohn credits with the potential for superstition,
idolatry, and speculative excess. Because hieroglyphic signs have no
prototype in nature, they provided potent material for superstition
and, indeed, Mendelssohn refers to the need for written signs as
"the first occasion [*Veranlassung*] for idolatry"
(*Jerusalem* (1983), p. 113 (translation slightly
altered)/*Gesammelte Schriften* 8, p. 179).



In the second chapter of *Jerusalem*, this general account of
language and its development figures prominently in an argument that
Judaism is a form of supernatural legislation rather than revelation.
By regarding language as primarily a living dialogue between persons,
Judaism does not lose sight of its communicative function for the sake
of thought. As a result, theory and speculation remain tied to
historical practice and concrete action. Not coincidentally, the
language of Judaism is primarily prescriptive rather than descriptive;
even its written prescriptions are "largely incomprehensible
without unwritten commentaries ... transmitted by oral
instruction." Hence, the use of language in Judaism -- its
script and ceremonial laws -- fends off the all too human
tendency to idolize the language itself.



The appeal to tradition (oral instruction) is necessary, Mendelssohn
adds, given the fact that, over the course of time, the laws
themselves become unintelligible "since no words or letters
retain their sense unchanged from one generation to the next"
(*Jerusalem* (1983), p. 128 (translation slightly
altered)/*Gesammelte Schriften* 8, p. 193). In chapter 1 of
*Jerusalem* he makes a similar claim after noting (a) the
elusiveness of inner perceptions to the perceiver herself and (b) the
impossibility of two people using the same words to express the same
"inner perceptions" (*Jerusalem* (1983), p.
66/*Gesammelte Schriften* 8, pp. 133f). Where the words in
question designate inner perceptions, there is no possibility of
ostensive definition, no more when uttered today than when uttered
ages ago. Indeed, in a passage that suggests both the inscrutability
and endless deferral of reference, Mendelssohn observes that
"words cannot be explained [*erlautert*] by
*things*. Instead, we must again have recourse to signs and
words and, ultimately, to metaphors" (*Jerusalem* (1983),
p. 66/*Gesammelte Schriften* 8, pp. 133f). Nonetheless,
Mendelssohn is more confident about words designating objects of
external perceptions and about the prospects for mutual understanding
in regard to them. Not incidentally, ceremonial law's ritualized
character calls for a recurrent context (including specific objects
and persons) available to external perception in the course of an
exchange between persons (including God). Notably, 'you'
and 'we' take precedence over 'I' and
'it' in such contexts, as the living references of the
former indexicals enables one to refer effectively to oneself and to
things generally.



Thus, in *Jerusalem* Mendelssohn stresses the ritual and
performative character of language, thereby complementing his view of
the inextricability of language and a reason that tempers speculation
with common sense. The mature Mendelssohn, keenly aware of the perils
of ostension in determining reference, tempers the claims of
speculation with those of common sense and is more concerned with
bridging theory and practice in the rites of language than in the
claims of pure theory. Nor should it be forgotten that
Mendelssohn's recognition of language's basically
ritualistic and empathic character, as a springboard to reason, is
rooted in what he regards as the possibilities of Judaism (for review
of Mendelssohn's philosophy of language, including the
significance of translation and language's political meaning for
him, see Schorch 2012).


## 9. Controversy with Jacobi over Lessing's alleged pantheism



Mendelssohn enjoyed, as noted at the outset, a lifelong friendship
with G. E. Lessing. In addition to their work as co-editors, Lessing
anonymously published Mendelssohn's earliest works and
collaborated with him on the piece: *Pope, a Metaphysician!*
Through his popular plays, his influential work as a dramaturg, and
his stormy public debates with orthodox Lutheran clergy, Lessing was a
particularly daunting and engaging spokesman for the German
Enlightenment, making him all the more dangerous to its opponents. His
final work, *Nathan the Wiseman*, fittingly portrays a Jewish
sage (presumably modeled on Mendelssohn) who makes a poignant plea for
tolerance by arguing that the differences among religions are
essentially matters of history and not reason. Along with Mendelssohn,
Lessing embraced the idea of a purely rational religion and would
endorse Mendelssohn's declaration: "My religion recognizes
no obligation to resolve doubt other than through rational means; and
it commands no mere faith in eternal truths" (*Gesammelte
Schriften*, Volume 3/2, p. 205). To pietists of the day, such
declarations were scandalous subterfuges of an Enlightenment project
of assimilating religion to natural reason. Mention has already been
made of Lavater's attempt to draw Mendelssohn into religious
debate. While Mendelssohn skillfully avoided that confrontation, he
found himself reluctantly unable to remain silent when, after
Lessing's death, F. H. Jacobi contended that Lessing embraced
Spinoza's pantheism and thus exemplified the
Enlightenment's supposedly inevitable descent into
irreligion.



Following private correspondence with Jacobi on the issue and an
extended period when Jacobi (in personal straits at the time) did not
respond to his objections, Mendelssohn attempted to set the record
straight about Lessing's Spinozism in *Morning Hours*.
Learning of Mendelssohn's plans incensed Jacobi who expected to
be consulted first and who accordingly responded by publishing,
without Mendelssohn's consent, their correspondence --
*On the Teaching of Spinoza in Letters to Mr. Moses
Mendelssohn* -- a month before the publication of *Morning
Hours*. Distressed on personal as well as intellectual levels by
the controversy over his departed friend's pantheism,
Mendelssohn countered with a hastily composed piece, *To the
Friends of Lessing: an Appendix to Mr. Jacobi's Correspondence
on the Teaching of Spinoza*. According to legend, so anxious was
Mendelssohn to get the manuscript to the publisher that, forgetting
his overcoat on a bitterly cold New Year's eve, he delivered the
manuscript on foot to the publisher. That night he came down with a
cold from which he died four days later, prompting his friends to
charge Jacobi with responsibility for Mendelssohn's death.



The sensationalist character of the controversy should not obscure the
substance and importance of Mendelssohn's debate with Jacobi.
Jacobi had contended that Spinozism is the only consistent position
for a metaphysics based upon reason alone and that the only solution
to this metaphysics so detrimental to religion and morality is a leap
of faith, that *salto mortale* that poor Lessing famously
refused to make. Mendelssohn counters Jacobi's first contention
by attempting to demonstrate the metaphysical inconsistency of
Spinozism. He takes aim at Jacobi's second contention by
demonstrating how the "purified Spinozism" or
"refined pantheism" embraced by Lessing is, in the end,
only nominally different from theism and thus a threat neither to
religion nor to morality.



Mendelssohn's criticisms of Spinoza are discussed below but
first the complexity of his relationship to Spinoza should be noted.
In his first publication, *Dialogues* (1761) he argued that
many of Spinoza's views were compatible with "true
philosophy and religion." In Mendelssohn's mind, Leibniz
may have given that "true philosophy" its sharpest
formulation but in all likelihood by deriving its central idea of a
preestablished harmony from Spinoza. Moreover, as Mendelssohn puts it,
Spinoza does not so much deny the distinctiveness of the actual world
as construe it as it is in the mind of God before the creation,
existing only as a part of God (*Philosophical Writings*,
102ff, 108ff). A quarter of a century later, Mendelssohn recapitulates
the latter argument as the key to understanding a
"purified" or "refined" Spinozism that
Lessing, at least in the realm of philosophical debate, would not have
dismissed out of hand.



Nevertheless, as noted above, part of his response to Jacobi consists
in demonstrating the shortcomings of Spinoza's philosophy. As
might be expected, he criticizes Spinoza's idea that there is
only one, infinite, and necessary substance. The idea is arbitrary,
Mendelssohn contends, since one can legitimately distinguish between
what is independent or self-standing (*das Selbstandige*)
and what obtains or persists for itself (*das
Fursichbestehende*). "Instead of proving that
everything obtaining for itself is only one, he [Spinoza] establishes
in the end only that everything independent is one. Instead of
demonstrating that the entire aggregate of everything finite
constitutes a single self-standing substance, he merely shows that
this aggregate must depend upon the sole infinite substance"
(*Gesammelte Schriften*, 3/2, p. 107).



On a "deeper level," as Mendelssohn puts it, he also takes
issue with Spinoza for failing to account for what Mendelssohn deems
the "formal" aspects of both corporeal and spiritual
worlds. Thus, Spinoza's conception of extension in terms of
impenetrability may explain "the essence of matter," but
it leaves unexplained, Mendelssohn contends, the particular
organization and movement of bodies. What is unclear to Mendelssohn is
how parts can be in motion if the whole upon which they completely
depend (Spinoza's substance) is not in motion. Similarly, he
wants to know how, on the basis of Spinoza's account of the
supposedly underlying attribute of extension, those parts come to have
the particular form and organization of motions and forces that they
have, that is to say, as organic, self-regulating entities.
"Where can the origin of this [motion and form] be found?"
he asks. "Not in the whole, since the whole has no movement. The
sum [*Sammtliche*] of all bodies, untied into a single
substance, cannot change place and has neither organization nor
figure.... Whence the form in the parts, if the whole provides no
source for this?" (*Gesammelte Schriften*, 3/2, p.
108).



Just as Spinoza explains the matter but not the form of the physical
world, so, too, Mendelssohn charges, he gives an account of the matter
but not the form of the spiritual world. In this connection it is
helpful to recall Mendelssohn's differentiation of knowing,
approving, and desiring from one another. Truth and falsity,
corresponding to knowing, provide the matter of the spiritual world.
While they may, as Spinoza maintains, have their origin in thought as
the attribute of a single, infinite substance, categories
corresponding not to knowledge but to approving or desiring must have
some other source. Thus, according to Mendelssohn, Spinoza leaves
unexplained "the difference between good and evil, desirable and
undesirable, pleasure and pain" (*Gesammelte Schriften*,
III/2, p. 109).



Yet, while some of these criticisms of Spinoza may be compelling, they
do not, Mendelssohn recognizes, carry the day for a refined Spinozist
or pantheist. Spinoza's inability to explain how movement and
values derive from the attributes of the one, infinite substance does
not, by itself, establish the theist explanation in
Mendelssohn's view. Accordingly, in *Morning Hours* he
casts Lessing as the spokesperson for a refined pantheism -- a
move that figures prominently in this contribution to the
*Pantheismusstreit*. Lessing is portrayed as someone who, while
agreeing with Mendelssohn's theist position, has a knack for
giving every reasonable argument its full due. In this context Lessing
presents a pantheism that characterizes the one and only substance,
not only as a source of motion and desire, but also as capable of
representing every possibility to itself and approving that
possibility that constitutes "the best and most perfect series
of things" (*Morning Hours*, p. 84/*Gesammelte
Schriften* 3/2, p. 115). In other words, refined pantheism
includes every aspect of the entire metaphysical system of theism but
casts it solely as the object of divine intellect. As a result, a
refined Spinozist might wonder how different the positions are since
the theist purports to explain these seemingly recalcitrant phenomena
merely by appealing to the divine will. A refined pantheist might
accept the difference between the world (thought) and God (thinker) at
a certain level, but insist that, in the end, the difference is on a
merely abstract level since thinking and thought can only be
distinguished as long as one is not actually thinking. After all,
"who is to tell us that we ourselves and the world surrounding
us have something more to them than the thoughts of God and
modifications of his original power?" (*Morning Hours*,
p. 84 (translation slightly altered)/*Gesammelte Schriften*,
3/2, p. 116). To pretend to show that there is something that can be
predicated of things outside God that cannot be predicated of the
divine thoughts of those things is to deny divine omniscience.



But, without further qualifications, this pantheist line of reasoning
is faulty, Mendelssohn submits, for at least three reasons. In the
first place, it abolishes a distinction presupposed by any truthful
statement, i.e., the distinction between original and copy. Secondly,
there are indefeasible marks that distinguish a finite
self-consciousness (as an object and original) from the divine
representation (copy) of it. "Consciousness of myself, combined
with complete ignorance of everything that does not fall within my
sphere of thinking, is the most telling proof of my substantiality
outside God, of my original existence" (*Morning Hours*,
p. 85 (translation slightly altered)/*Gesammelte Schriften*,
3/2, p. 118). Finally, the pantheist confuses divine knowledge with
divine approval. God knows perfectly well my shortcomings without
approving them and requiring their existence. Moreover, that they are
thinkable hardly explains their existence since the opposite of them
is just as thinkable. The problem for the pantheist, Mendelssohn
submits, is explaining their existence, i.e., explaining what
privileges some divine thoughts over others.



For the theist, by contrast, there is a ready solution to the problem.
"The thoughts of God that come to reality to the exclusion of
the rest will have this prerogative by virtue of their relative
goodness and purposiveness, insofar, namely, as they correspond thus
and not otherwise, here and now, to the idea of the perfect and
best" (*Morning Hours*, p. 89/*Gesammelte
Schriften* 3/2, p. 122).



Still, the difference between the theist and a refined pantheist is by
no means this simple, Mendelssohn is quick to add. To be sure, Spinoza
conceived intellect and will as one and the same. Nevertheless, at
least as Lessing understood him, Spinoza also differentiated
acquaintance with what is true from acquaintance with what is good and
identified knowledge of the good with the "will" insofar
as through it one thought does have a prerogative over another.
Pantheism, so refined, secures religion and morality no less than
theism does, such that, assuming as much, Mendelssohn is led to ask:
"in what way now does the system defended by my friend [Lessing]
differ from ours?" (*Morning Hours*, p. 89/*Gesammelte
Schriften*, 3/2, p. 123). Seen in this light, the difference
between theism and refined pantheism turns in the end on a speculative
subtlety without practical consequences, namely, on different
interpretations of the metaphor of divine light. Mendelssohn
accordingly concludes that, like many another dispute in metaphysics
and epistemology, the dispute between refined pantheists and
traditional theists is purely verbal.