Plato

1
Platos 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 Platos 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 .

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II. Definitions

• 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.

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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.
• 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.

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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.

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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.

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III. Two Different Worlds

• 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.

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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.

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Platos 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 Platos 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.

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Platos Theory of Forms

• 1. Platos 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.

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Platos 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.

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Platos Theory of Forms

• What made Platos 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.

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Platos Theory of Forms

• Not only was Platos 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.

13
Platos Theory of Forms

• Examples of such glimpses into the ideal world
  are available in the fields of mathematics and
  geometry. For example, lets consider the
  geometrical proof of a theorem having to do with
  triangles.

14
Platos Theory of Forms

• Lets 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 isnt a triangle at
  all. And yet, by using this poor drawing of a
  triangle, something essential about triangles can
  nevertheless be proven.

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Platos 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-as-such. 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.

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Platos 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.

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Platos 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.

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Platos Theory of Forms

• Begins with image of a number of prisoners
  shackled in a cave with faces to the wall.
• 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.

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Platos Theory of Forms

• 3. Lets 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?

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Platos Cave
21
Platos 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?.

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Platos Theory of Forms

• 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.

23
Platos 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.

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Basic Argument of Platos 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.

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Where do the Forms Exist?

• Have an independent existence
• They have no spatial dimension
• Human soul was acquainted with Forms before it
  was united with the body.
• 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.
• 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.

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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.

27
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.
• Aristotles 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.

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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.

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What is the Relation of Form to Each Other?

• Example The closer one comes to discussing a
  black dog, the less universal is ones knowledge.
  Conversly, the higher one goes, the more
  abstract the Form, as when one speaks of Dog in
  general, the broader ones 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.

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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.

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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.

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IV. What Do the Forms Do

• They are postulated to solve certain
  philosophical problems
• Epistemological Responding to his conception of
  Heraclitus theory Objects in flux cant 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.

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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
  Platos 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.

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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

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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.

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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

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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).

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V. Arguments for the Forms

• Argument by generalized this way
• 1. Either we know something (i.e., at least one
  thing) or we know nothing.
• 2. 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 dont 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.

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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).

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V. Arguments for Existence of Forms

1. 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.

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V. Arguments for Existence of Forms

• 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.

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V. Arguments for Existence of Forms

• 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 were talking
  about? Platos answer is the Form of Justice,
  the one over the many.

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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 Platos 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.

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EvidencesPlatos evidence is largely Intuitive

• 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.

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EvidencesPlatos 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.

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EvidencesPlatos 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?

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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 chairs-though
  Plato certainly seems on occasion to have done so.

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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.

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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.

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Problems

• 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.

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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
  cant 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).

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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.

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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 MODES OF THOUGHT
The Good Forms Mathematical
Objects Things Images
Knowledge
Thinking Belief Imagining
The Good Intelligible World
Knowledge
The Sun Visible World
Opinion
Lower degree of reality truth in visible world.
x
Dark shadowy world at X and moving up to bright
light at Y going from x to y represents a
continuous process of minds enlightenment.
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What did Plato Oppose?

• In Platos writings we observe that he opposed
  seven prevalent beliefs
• Hedonism
• Empiricism
• Relativism
• Materialism
• Mechanism
• Atheism
• Naturalism

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Contrasts between Plato Aristotle

• More interested in mathematics
• 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.

• More interested in empirical data.
• 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 Platos explanation of the
  universal Forms, rejecting specifically the
  notion that the Forms existed separately from
  individual things.
• Aristotle oriented his thought to dynamic realm
  of becoming.

56
Points of Differences

• Plato
• 1. There is a priori knowledge (Meno)
• 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.

57
Points of Differences

•  Aristotle (384-322 BC, Platos 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).
• 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

58
Points of Differences

• 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.
•