Plato’s Theory of Forms
“Whether we like it or not, whether we know it or not, we are all more or
less Platonists. Even if we reject Plato’s conclusions, our views are
shaped by the way in which he stated his problems.”
~ W. T. Jones, History of Philosophy: The Classical Mind, 108.
“…the copies of the eternal things [are] impressions taken from them in a
… manner that is hard to express ….”
II. Definitions:
A.
Forms are called “Ideas” (eidos). They are not mental but extramental
entities, that is, they are not mind-dependent. Rather, they are independently
existing entities whose existence and nature are graspable only by the mind,
even though they do not depend on being so grasped in order to exist.
B.
They are eternal and unchanging entities, which are encountered not in
perception but in thought.
II. Definitions:
C.
Forms are eternal patterns of which the objects that we see are only copies
(e.g., a beautiful person is a copy of Beauty). We can say about a person that
she is beautiful because we know the Idea of Beauty and recognize that a
person shares more or less in this Idea.
D.
Knowledge seeks what truly is: its concern is with Being.
E.
What really is, what has Being, is the essential nature of things: these
essences, such as Beauty and Goodness, which make it possible for us to
judge things as good or beautiful, these are eternal Forms or ideas.
F.
Science: is a body of universal and necessary truths. Every science has its
objects, and must have for its objects, forms: nothing other than eternal,
unchanging forms can qualify to be the objects of scientific knowledge.
II. Definitions:
What Plato means by the Forms is that
they are the essential archetypes of
things, having an eternal existence,
apprehended by the mind, not the senses,
for it is the mind that beholds “real
existence, colorless, formless, and
intangible, visible only to the intelligence.
III. Two Different Worlds:
• A. Though the Forms are never systematically argued for, we
primarily gain our understanding of them from Phaedo and
Republic.
• B. The correct answer to the question, “What is X?” is one that
gives an accurate description of an independent entity, a
Form.
• C. Forms are extramental, independent entities; their existence
and nature is independent of our beliefs and judgments about
them.
III. Two Different Worlds:
D.
The Phaedo contains an extended description of the characteristics and
functions of the Forms:
1. Unchangeable (78c10-d9)
2. Eternal (79d2)
3. Intelligible, not perceptible (97a1-5)
4. Divine (80a3, b1)
5. Incorporeal (passim)
6. Causes of being (“The one over the many”) (100c)
7. Are unqualifiedly what their instances are only with qualification (75b)
8. Non-temporal (Tim. 37e-38a)
9. Non-spatial (Phaedr. 247c)
10. They do not become, they simply are (Tim. 27d3-28a3)
11. Phaedo 80b provides a good summary, listing all the attributes of Forms
that souls also have “divine, deathless, intelligible, uniform, indissoluble,
always the same as itself.”
THE HIGHER WORLD:
1. Is composed of immaterial & eternal essence that we
apprehend through our minds.
2. A Form is an eternal, unchangeable, & universal essence
(they have an objective or extramental existence).
3. What we encounter in physical world are imperfect
examples of such unchanging absolutes as Goodness,
Justice, Truth, & Beauty that exist in an ideal, nonspatial
world.
4. The higher world is more real for Plato than physical world,
inasmuch as the particular things that exist in the world of
bodies are copies of the Forms.
5. Only when we focus on the Forms does genuine knowledge
become possible.
Plato’s Theory of Forms:
• Plato believed that we participate in two different
worlds: Upper world and lower world.
• One is the physical world that we experience
through our bodily senses. Thus, the our
contact with the “lower world” [ this phrase does
not appear in Plato’s writings but is helpful in
terms of clarification] comes through our bodily
senses, as seen in seeing and touching
particular physical objects like rocks, trees,
dogs, and people. The physical things that exist
in the “lower world” exist in space and time.
Plato’s Theory of Forms:
1.Plato’s cosmological concerns include the
Pythagoran view of the world as number
2.The Heraclitean view of the world as flux
and as logos,
3.Parmenidean vision of eternal,
unchanging, unknowable reality.
Plato’s Theory of Forms:
The upshot is a “two-world” cosmology:
An everyday world of change and impermance
and an ideal world populated by ideal ‘Forms” or
(Eidoi; singular is eidos).
The “World of “Becoming” is in flux, as
Heraclitus argued, but the “World of Being,” is
eternal and unchanging, as Parmenides
demanded.
Plato’s Theory of Forms:
What made Plato’s new vision appealing was
twofold:
1. The two worlds were interrelated, not unrelated
as Parminedes suggested. The World of
Becoming, our world was defined by
(“participated in”) the World of Being, the world
of ideal Forms. Thus, the idea of an
unchanging logos underlying the everyday world
could be understood as the ideality of the Forms,
defining the world despite the fact of continual
change.
Plato’s Theory of Forms:
Not only was Plato’s new vision appealing
because it interrelated the two-worlds, but
2. We can have a glimpse of this ideal world,
at least, through reason. Thus, the ideal
world of Forms was not, as in Parmenides,
unknowable.
Plato’s Theory of Forms:
Examples of such glimpses into the ideal
world are available in the fields of
mathematics and geometry. For example, let’s
consider the geometrical proof of a theorem
having to do with triangles.
Plato’s Theory of Forms:
Let’s draw a triangle on this sheet of paper. It
is not perfect. In fact, given the way the lines
are smudged, crooked, and corners not quite
coming together, it really isn’t a triangle at all.
And yet, by using this poor drawing of a
triangle, something essential about triangles
can nevertheless be proven.
Plato’s Theory of Forms:
Pythagoras had already led the way in his theory that the essence of the
world could be found in number, in proportion, or ratio. What was most
real, Pythagoras, claimed, was not the matter of things but their form. The
study of mathematics and geometry, accordingly, was the study of the
essential structure of reality, whatever the passing fait of particular being s
and relationships. And so, we might say, the study of mathematics and
geometry allows us to ‘see through” the everyday flux of the world and
understand something essential, unchanging. So, too, we “see through” our
badly drawn triangle to the idea or form of a triangle-as-such. What we
prove is not so much a theorem about our badly driven drawn triangle as it
is a theorem about all triangles, insofar as they exemplify the triangle-assuch. Of course, our badly drawn triangle conforms to the theorem, too,
insofar as it is indeed a representation of a triangle. But that is just to say it
is a triangle by virtue of the fact that it is a representation of something
else, triangle-as-such, which is not in this world. And yet, we can evidently
know triangle-as-such, that is, the ideal Form of a triangle. We come to
understand it through our reasoning.
Plato’s Theory of Forms:
Likewise, all things in this world are
representations, for better or worse, of ideal
Forms.
Perhaps the most memorable image of the
Forms is the vision that Plato provides for us
in Book VII of the Republic.
Plato’s Theory of Forms:
The Myth of the Cave is an allegory
concerning the relationship between the World
of Being and the World of Becoming-the
Forms and the things of this world-and a
warning of the dangers facing the philosopher.
Plato’s Theory of Forms:
1.
Begins with image of a number of prisoners shackled in a cave
with faces to the wall.
2.
What they see and consider to be reality are the shadows cast on
the wall.
What we all take to be reality consists ultimately of shadows; it
is not that these are unreal. They are real shadows, but they are
shadows of things that are even more real. So the distinction
here is not, as in Parmenides, between reality and illusion. It is
the distinction between more and real less, a superior and an
inferior world.
Plato’s Theory of Forms:
3. Let’s suppose a prisoner breaks free and turns
around, casting his eyes, for the first time, on
the genuine objects that cast the shadows and
the bright sun that does the casting. Would not
he be dazzled? Would he not immediately see
how imperfect are the shadows of the everyday
reality compared with the reality he now
observed?
Plato’s Cave:
Plato’s Theory of Forms:
4. So, too, the philosopher is dazzled when he sees the
perfect Forms of virtue, justice, and courage, compared
to the imperfect and usually confused ideas and actions
of ordinary men and women. How much ‘higher” than
his aspirations will be.
5. And if such a philosopher were then to turn back to the
cave and try to tell his fellows how impoverished their
world was, how inadequate their ideals, would they not
turn on him and kill him? [an illusion to Socrates?].
Plato’s Theory of Forms:
6.
Upshot is that most of humanity dwell in the darkness of the
cave. They have centered their thoughts around blurred world
of shadows. It is the function of education to lead people out of
cave into world of light.
7.
Just as the prisoner had to turn his whole body around in order
that his eyes could see the light instead of the darkness, so also
it is necessary for the entire soul to turn away from the
deceptive world of change and appetite that causes a blindness
of the soul. Education, then, is a matter of conversion, a
complete turning around from the world of appearance to the
world of reality.
Plato’s Theory of Forms:
8. When those who have been liberated from the
cave achieve the highest knowledge, they must
not be allowed to remain in the higher world of
contemplation, but must be made to come back
down into the cave and take part in the life and
labors of the prisoners.
Basic Argument of Plato’s Theory of Forms:
1. Whenever several things are F, there is a single form of F-ness in
which they all participate. (That is to say, all these things are F in
virtue of sharing in the characteristics of the form of F-ness.)
2. The form of F-ness is perfectly F.
3. The form of F-ness does not participate in itself. (Because whatever
participates in something is inferior to that thing, and nothing is
inferior to itself).
4. The form of F-ness has all and only those characteristics which all
the things that participate in it (the particulars of the form) have in
common, in virtue of being F.
Where do the Forms Exist?
1.
Have an independent existence;
2.
They have no spatial dimension;
3.
Human soul was acquainted with Forms before it was united with
the body.
4.
In the process of creation, the Demiurge or God used the Forms in
fashioning particular things, suggesting that the Forms had an
existence prior to their embodiment in things.
5.
Forms seem to have originally existed in the “Mind of God” or in
the supreme principle of rationality, the One.
6.
Whether the Forms truly exist in the mind of God is a question, but
the Forms are the agency through which the principle of reason
operates in the universe seems to be just what Plato means.
What is the relation of Forms to Things?
• A Form can be related to a thing in three ways, which
may be three ways of saying the same thing:
– Form is the cause of the essence of a thing;
– A thing may be said to participate in a Form;
– A thing imitates or copy a Form.
In each case, Plato implies that although aF rom is separate
from the thing, that the Idea of Man is different from Socrates,
still, every concrete or actual thing in some way owes its
existence to a Form, in some degree participates in the perfect
model of the class of which it is a member, and is in some
measure an imitation or copy of the Form.
What is the relation of Forms to Things?
In contrast, Aristotle argues that form and matter are
inseparable and that the only good or beautiful was found
in actual things. But Plato, only allows participation and
imitation as the explanation of the relation between
things and their Forms. In fact, it was the Forms through
which order was brought into chaos, indicating separate
reality of form and matter.
Aristotle’s criticism is critical to note: there is no coherent
way of accounting for the existence of the Forms apart
from actual things. But Plato might respond by asking
him how it is possible to form a judgment about the
imperfection of something if the mind does not have
access to anything more than the imperfect thing.
What is the Relation of Form to Each Other?
Plato contends, “We can have discourse only through the
weaving together of Forms.”
- Our language reveals our practice of connecting Forms
with Forms. There is the Form animal and the
subclasses of Forms as Man and Horse. Forms, are,
therefore, related to each other as genus and species. In
this way Forms tend to interlock even while retaining their
unity. Ever significant statement involves the use of
some Forms and that knowledge consists in
understanding the relations of the appopriate Forms to
each other.
What is the Relation of Form to Each Other?
Example: The closer one comes to discussing a
black dog, the less universal is one’s knowledge.
Conversly, the higher one goes, the more
abstract the Form, as when one speaks of Dog in
general, the broader one’s knowledge.
Example: The animal vet proceeds in knowledge
from this black dog to Schnauzer to Dog. As one
proceeds upward one moves towards
abstraction or independence from particularss of
which Plato was thinking.
How Do We know the Forms:
Three different ways in which the mind discovers the Forms:
1.
Recollection: Before it was united with the body, the soul was
acquainted with the Forms. People now recollect what their
souls knew in their prior state of existence. Visible things
remind them of the essences previously known. Education is
actually a process of reminiscence.
2.
People arrive that knowledge of Forms through the activity of
dialectic: the power of abstracting the essence of things and
discovering the relations of all divisions of knowledge to each
other.
How Do We know the Forms:
Three different ways in which the mind discovers the Forms:
3.
The power of desire, love (eros) which leads people step by
step, as Plato described in the Symposium, from the beautiful
object to the beautiful thought, and then to the very essence of
beauty itself.
IV. What Do the Forms Do:
•
They are postulated to solve certain philosophical
problems:
1. Epistemological: Responding to his conception of
Heraclitus’ theory: Objects in flux can’t be known.
2. Metaphysical: Two-world theory (Republic VII): The
intelligible world is Parmenidean, the visible world is
Heraclitean. Forms in the intelligible realm are
postulated to be the objects of knowledge. The
metaphysical theory is designed to fit epistemological
requirements.
V. Arguments for the Forms:
• We can summarize our discussion by stating that “by
‘forms’ Plato means eternal and unchanging entities,
which are encountered not in perception but in thought.
They constitute the public world that the Sophists had
denied and that function at once as the objects of the
sciences-physical, moral, and social-and the objective
criteria against which our judgments in these inquiries
are evaluated. As the objects of thought, the forms
justify thought in looking for objects. Without the forms
there would be nothing, in Plato’s view, to look for, and
every individual would remain forever isolated in the
cave of his own subjective states.
But are there forms? Do forms such as Plato described
actually exist?” W.T. Jones, History of Philosophy, 143.
V. Arguments for the Forms:
• In general, proofs for forms involved a
challenge to find in the changing world of
sense perception anything adequate to be
an object of knowledge. Thus, we might
argue for forms this way:
V. Arguments for the Forms:
Questioner: “Do you allow there is a knowledge of triangles?”
Doubter: Yes.
Questioner: “Well, what is the triangle about which you admit there is
knowledge? Not this or that particular drawn triangle, for none of
these sense objects has exactly the qualities in question. They are
not really triangles. Hence, if you admit that there really is such an
object as a triangle and that we knowledge of it, you have to admit
that there are non-empirical, non-sensible things. These objects are
the forms.
We see this same approach in the Phaedo in connection with the notion
of equality.
V. Arguments for the Forms:
In the Phaedo discussion Socrates and Simmias move from
a proof of the existence of forms to a proof of the
transmigration of the soul, by arguing that our knowledge
of forms can be accounted for only on the assumption that
we existed before we were born into this world.
Consider W.T. Jones comments on this argument:
V. Arguments for the Forms:
This argument is certainly not without force. It would be
hard to deny that we know what equality is-how otherwise
could we know that any two sticks are unequal? To
observe that, we must apply the criterion of equality and
find them wanting. And since it is agreed that sticks are
never absolutely equal, our knowledge of this criterion
cannot have been derived from sensory experience. Thus
the empirical fact, which no one would deny, that we judge
the sticks to be unequal proves both that we have a
knowledge of equality and that this equality cannot be
physical (pg. 145).
V. Arguments for the Forms:
Argument by generalized this way:
1.
2.
Either we know something (i.e., at least one thing) or we
know nothing.
Suppose you opt for the second alternative. Either you claim to
know that the second alternative is true or you do not make this
claim.
a
If you don’t claim to know that the second alternative is
true, we throw out your reply as worthless.
b.
If you do claim to know that the second alternative is
true, you have contradicted yourself. For by your own
account there is not at least one thing you claim to know,
namely, that you know nothing.
V. Arguments for the Forms:
3. Hence, the first alternative is true: there is at least one
thing that is known.
4. Therefore, knowledge is possible.
5. It follows that forms exist, for only forms have the
characteristics-immutability, eternity-requisite for
knowledge.
We see this line of argument in the Timaeus in which Plato
merely points out that if there is knowledge (as distinct
from opinion) there must be forms (as distinct from sense
objects) (Ibid., 145).
V.
Arguments for Existence of Forms:
C. Imperfection Argument: Forms are the real
entities to which the objects of our sensory
experience (approximately) correspond. We
make judgments about such properties as
equal, circular, square, etc. even though we
have never actually experienced any of them
in perception. Forms are the entities that
perfectly embody these characteristics we
have in mind even though we have never
experienced them perceptually.
V.
Arguments for Existence of Forms:
D. Argument From Knowledge (“from the
sciences”): What is our knowledge ‘about’?
When we know something, what is our
knowledge of? Plato supposes that there is a
class of stable, permanent, and unchanging
objects that warrant our knowledge claims.
V.
Arguments for Existence of Forms:
E. “One Over Many” argument:
“A famous passage in the Republic (596a) suggests a
semantic role for the Forms (“there is one Form for
each set of many things to which we give the same
name”). That is, when you use the word “just” and I
use the word “just,” what makes it one and the same
things that we’re talking about? Plato’s answer is: the
Form of Justice, “the one over the many.”
Strengths:
1. To say a thing is better or worse implies some standard, which
obviously is not there as such in the thing being evaluated.
2. Doctrine of the Forms makes possible scientific knowledge, for the
scientist has to ‘let go’ of actual visible particulars and deal with
essences or universals, that is, with ‘laws.’ The scientists formulates
‘laws,’ and these laws tell us something about all things, not only the
immediate and particular things.
3. “Though” Plato’s metaphysics rests upon the view that ultimately
reality is nonmaterial, it goes a long way toward explaining the more
simple fact of how it is possible for us to have ordinary conversation.
For any discourse between people, illustrates our independence
from particular things.
Evidences:
Plato’s evidence is largely Intuitive:
1. The argument from human perception:
• We call both the sky and blue jeans by the same color: Blue.
However, clearly a pair of jeans and the sky are not the same
color; moreover, the wavelengths of light reflected by the sky
at every location and all the millions of blue jeans in every
state of fading constantly change, and yet we somehow have
an idea of the basic form Blueness as it applies to them.
Evidences:
Plato’s evidence is largely Intuitive:
• But if the very nature of knowledge changes, at the time when
the change occurs there will be no knowledge, and, according
to this view, there will be no one to know and nothing to be
known: but if that which knows and that which is known exist
ever, and the beautiful and the good and every other thing also
exist, then I do not think that they can resemble a process of
flux, as we were just now supposing.
Evidences:
Plato’s evidence is largely Intuitive:
The argument from perfection:
• No one has ever seen a perfect triangle, nor a perfectly straight
line, yet everyone knows what a triangle and a straight line are.
... when a man has discovered the instrument which is
naturally adapted to each work, he must express this
natural form, and not others which he fancies, in the
material ....
Perceived circles or lines are not exactly circular or
straight, but if the perfect ones were not real, how could
they direct the manufacturer?
Problems:
1. Generality Problem:
If this is supposed to be a theory applying to all
possible substitutions of F, then we would have to
accept the existence of the Forms of perfect mud,
perfect Stink, etc.
Plato offered this criticism himself in the Parmenides.
But Platonism can survive with a very limited number of
forms. It is not necessary to assume a separate form for each
physical object, nor for man-made objects, like beds or chairsthough Plato certainly seems on occasion to have done so.
Problems:
2. The “Third Man”
Several individuals are men. Therefore, there is a form of Man in
which they all participate. The form of Man is a man (indeed, the
Perfect Man). So all individual men plus the form of Man taken
together are all men. So there is a single form in which they all
participate. This new form cannot be the form of Man, for then it
would have to participate in itself which is impossible, so this has to be
a Third Man (besides the singular men and their form). But we can
repeat the same reasoning for this Third Man as well, so there would
have to be a Fourth, a Fifth, Sixth, etc. to infinity. So for a set of
individuals there would have to be an infinity of Forms. But the
Theory also states that there is only a single Form for any set of
individuals. So the theory is inconsistent, whence it cannot be true.
Problems:
3. Inconsistency of Characteristics
The perfect Form of F-ness has to have all and only those
characteristics, which are common to all its particulars. But all these
particulars are necessarily either G or not G. (Say, any triangle must
be either isosceles or scalene.) So the Form also has to be G or not G.
(Say the Form of triangle must be either isosceles or scalene.) But since
not all particulars are G, the Form cannot be G. (Since not all triangles
are isosceles, the Form of triangle cannot be isosceles.) And since not
all particulars are not G, the Form cannot be not G either. (Since not
all triangles are scalene, the Form of triangle cannot be scalene either.)
So the Form has to be either G or not G and yet it cannot be G and it
cannot be not G. (The Form of triangle has to be either isosceles or
scalene, but it cannot isosceles and it cannot be scalene either.) But this
is impossible, so the theory cannot be true as stated.
Problems:
4.
Forms and sense objects are too separate; ideal and
actual are separated by an unbridgeable criticism.
Transcendence creates a grave problem:
If the forms are not apart, they are not (Plato thought)
true objects, and if there are no form-objects, there is
nothing to have knowledge of. On the other hand, if they
are apart, they are unknowable.
Plato bridges the chasm between intelligible world and
sensible world by means of appealing to the soul. The
soul is immortal and supremely valuable.
Problems:
W.T. Jones comments that it is a challenge to account for the
possibility of knowledge in any way other than on the assumption of
fomrs. But no proof of this type ever establishes conclusively the
proposition it is intended to maint; it always rests on the inability of
the critic to find an alternative explanation. This is weak, since (1)
even if the critic himself can’t find an alternative, there may be one,
and (2) he may find it (Ibid., 146).
Many people account for the certainty of mathematics
differently. Mathematics is certain, they say, not because it is about
nonphysical, as distinct from a physical, object but because it is not
about objects at all. Mathematical certainty results from the fact that
propositions of mathematics are all tautologies (redundant
language).
Soul Mediates Transcendence:
1. The soul (psyche) is like the forms; it is eternal
and immortal; it has a kind of unchanging
identity.
2. One part of the psyche must be like the sense
world. The emotions and passions have their
seat in the lower parts of the psyche whereas the
mind has the highest part of the pyshe (higher
and more real world). For these reasons, soul is
well suited to serve as a link between sensible
and intelligible worlds, to redeem from utter
unreality and to mediate the splendid but awful
purity and isolation of the latter.
In the process of discovering true knowledge the mind moves through 4 stages of
development. At each stage, there is a parallel between the kind of object presented to the
mind & the kind of thought this object makes possible. The vertical line from x to y is a
continuous, suggesting that there is some degree of knowledge at every point. But as the line
passes through the lowest forms of reality to the highest, there is a parallel progress from the
lowest degressof truth to the highest. The line is divided into two unequal parts.
y
Greater reality
& truth found
in intelligible
world.
OBJECTS
The Good [Forms]
MODES OF THOUGHT
Knowledge
[The Good]
Intelligible World
Mathematical
Objects
Knowledge
Thinking
[The Sun]
Visible World
Lower degree of
reality & truth in
visible world.
Things
Belief
Images
Imagining
Opinion
x
Dark shadowy world at X and moving up to bright light at Y; going from x to y represents a
continuous process of mind’s enlightenment.
What did Plato Oppose?
• In Plato’s writings we observe that he
opposed seven prevalent beliefs:
– Hedonism
– Empiricism
– Relativism
– Materialism
– Mechanism
– Atheism
– Naturalism
Contrasts between Plato & Aristotle:
1. More interested in mathematics
1. More interested in empirical data.
2. Plato separated the world of
thought from the world of flux
and things, ascribing true reality
to the Ideas and Forms, which he
believed, and an existence
separate from the things in
nature. For Plato, the primary
stuff of space was molded by the
eternally existing Forms into
individual shapes.
2. Fixed upon concrete processes of
nature whereby he considered abstract
notions to have their real habitat in this
living nature. Everything that exists is
some concrete individual thing, and
every thing is a unity of matter &
form. Substance is a composite of
form & matter. Aristotle rejected
Plato’s explanation of the universal
Forms, rejecting specifically the notion
that the Forms existed separately from
individual things.
3. Aristotle oriented his thought to
dynamic realm of becoming.
Points of Differences:
Plato:
1. There is a priori knowledge (Meno)
2. Intellectual concepts of perfect objects needed for a priori
knowledge cannot be gained from experience (main argument from
Phaedo).
3. A priori knowledge = prenatal knowledge (theory of recollection in
Phaedo)
4. The objects of our intellectual concepts (i.e. the things we directly
conceive by means of our intellectual concepts) are the perfect
Forms.
Points of Differences:
Aristotle (384-322 BC, Plato’s student: amicus Plato sed magis
amica veritas – ‘I like Plato but I like the truth even more’)
1. Intellectual concepts needed for a priori knowledge can be gained
from experience, by abstraction (On the Soul).
2. A priori knowledge is not prenatal, but can be gained by induction
based on abstraction (Posterior Analytics).
3. The objects of our intellectual concepts are the natures (essences,
quiddities) of material things (On the Soul); these objects cannot be
the perfect Forms of Plato, for such perfect Forms cannot exist
Points of Differences:
3.
Is Aristotle a materialist (as a “harmony theorist” would be) or is
he an idealist (as is Plato) concerning the nature of the soul?
(That is to say: does he believe that the soul is just the organic
structure of the body, or does he believe that it is an immaterial,
spiritual entity inhabiting the body?)
Reply: he is a materialist concerning non-human souls, but he
also contends that the human soul, which has an immaterial
activity, namely, thinking, is not dependent for this specific activity,
and so neither for its being, on its union with the body; therefore,
the human soul (at least its intellective “part”), is immortal.