Under the argument of recollection, what would the answer to the following scenario?

A young child has not learned a single thing about geometrical shapes. If a person were to draw a triangle and show the child, the child, surely, would not know what this figure is. It would only be until the child is told that this is a triangle with the property of having three sides, with the angles equaling 180 degrees, and etc.

Since the argument of recollection argues that we do not gain knowledge through sense-perception, how are we ever supposed to be reminded of the Form of a triangle? Suppose that the child is never told explicitly that it is a triangle; does the child have some thought that this triangle represents something greater and intelligible? Or is it only when he starts to see multiple triangles (each one increasing in its participation in the Form of the triangle) that he starts to recognize the idea of absolute "triangle-ness?"

Wouldn't this also imply that it requires sense-perception to even acquire knowledge about the thing itself, let alone the Form of the thing?

  • "with each angle equaling 180 degrees" I am not sure about that. Not sure that the child would knew that property instantly. Also, triangles can be curvy.
    – rus9384
    Commented Jan 28, 2019 at 6:26

3 Answers 3


In the argument in the Phaedo (72e), Socrates assumes the existence of a class of entities, the 'forms', such as those of beauty, goodness, justice and equality, which are not accessible to sense perception, and distinguishes them from their sensible instances.

our learning is nothing else than recollection, [...] we must necessarily have learned in some previous time what we now remember.

[73c] If a man, when he has heard or seen or in any other way perceived a thing, knows not only that thing, but also has a perception of some other thing, the knowledge of which is not the same, but different, are we not right in saying that he recollects the thing of which he has the perception?

Thus, a preliminary comment is : perception is not knowledge. Perception is about particulars; while knowledge is about the "general" :

[74a] We say there is such a thing as equality. I do not mean one piece of wood equal to another, [...] but something beyond that — equality in the abstract. [...] Whence did we derive the knowledge of it? [...] Did we not, by seeing equal pieces of wood or stones or other things, derive from them a knowledge of abstract equality, which is another thing?

Thus, knowledge is based on the activity of "subsuming" a particular under a general concept, recognizing the first one as an "instance" (but Plato says : "a copy") of the latter.

Our "current" act of knowledge is bootstrapped by an act of perception, but it needs recollection of forms to give us full knowledge.


Welcome, Richard.

The child does not gain knowledge through sense experience, as you rightly represent the argument. S/he already has knowledge through acquaintance with the Forms in previous incarnations.

Recollection - recognition - is possible because there is a resemblance between sensible particulars and the Forms in which they 'participate' (metechei). Even though a particular that participates in F, a Form, is imperfectly F, it is sufficiently similar (echomen) to F for recollection of the from F to be activated by sense experience of the particular. The child is reminded of F by the particular's resemblance to F.


Norio Fujisawa, '῎Εχειν, Μετέχειν, and Idioms of 'Paradeigmatism' in Plato's Theory of Forms', Phronesis, Vol. 19, No. 1 (1974), pp. 30-58.

David Sedley, 'Form-Particular Resemblance in Plato's "Phaedo"', Proceedings of the Aristotelian Society, Vol. 106 (2006), pp. 311-327.



...[Ralph] Cudworth [, the 17th century Cambridge Platonist] regarded all material individual things as mutable. Knowledge is not of such things. Knowledge is the active apprehension of that which has necessary identity with itself.


As we approach [any] particular triangle, its bluntness and its irregularity become marked, we discover in it but a feeble resemblance to our intelligible idea...If all triangles were first from sense, we should possess no standard of perfection...There is no numerical relation impressed by sense. On the contrary, the intelligible idea of a triangle is peculiarly susceptible to computation...The mind...can understand a triangle in general without determining the particular species.


Cudworth now enters into argument, more extensively than heretofore, to establish that the activity of outward objects has nothing of efficiency in the creation of rational ideas, even in reference to those individual things, color, sound, and light. We have not a satisfactory comprehension of those things which make the strongest impression upon our senses. Mind asks even concerning the nature of color, sound, and light. It desires to conquer these most clear sense-perceptions by some of its own conceptions. If sense is not knowledge, then that which is derivative must be more obscure. If knowledge were derivative from sense, it would be the weaker perception. Since the contrary is the case, the mind must exert active power upon that which is passively received. Besides sensible ideas there must be intelligible ideas, the product of the self-activity of mind, to understand the significance of the sensibles.


Sense, then, is simply the ectypal impress of the archetypal mind upon the finite mind, supplied as an occasion from which the finite mind by self-activity may become a perfect echo [or recollection] of the Perfect. "Be ye therefore perfect, even as your Father which is in heaven is perfect," is man's noble privilege. But to become so, man, by his own free activity, must put himself in harmony with God, with the universal brotherhood of humanity, and with himself.


A commonwealth is a creation of the mind. Even the most mechanical or outward relations owe their existence to the active principle of intelligence; e.g., a house is [i.e., exists], in the fact that it expresses a notion of fitness for its end, that it is a proper residence for man in the performance of the functions of his life. The true form of an animal, also, we do not derive from sense; we get no notion of a totum from sense.

We do not discard sense; it has its place. What we object to is, that it be made arbitrarily to change place with intellect. There is rather a nature or wisdom in all artificial things, and artifice in all natural things. Sense, however, touches as mind sees, and sees as mind comprehends the whole. Corporeal objects, therefore, are [i.e., exist] only as they include these relative conceptions of the mind's creation. If this is the case in reference to relative essences, much more is it true of goodness, justice, etc., that are modes of intelligent beings, or express relations between them.

So...in the contemplation of the material universe or cosmos, the mind has occasion to conceive that this is the passive impress or stamp of wisdom, and thus excites within itself the conception of the divine Wisdom. When it considers, further, that not only for the beauty [or elegance] of the whole, but also for the good of every living part, each part is contrived, the conception of goodness and that of morality are excited. When goodness and morality are regarded as modes of intelligent Being, we gain the idea of God as perfect. Sense could not have heard the least word concerning a Creator from the tumult of the numerous visible characters impressed upon it; but mind finds in sense an occasion to re-echo [or recollect] the name[, "Father"].


  • The Cambridge Platonist Research Group
  • Stanford Encyclopedia of Philosophy
  • The Philosophy of Ralph Cudworth, by Charles E. Lowrey

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