Post #3 of my commentary on Heidegger’s anaylsis of Plato’s Theaetetus, written in the lead up to my exhibition: The Aviary
The first answer that Theaetetus offers, in response to Socrates’ question: “what is knowledge?,” is that knowledge is perception (aisthesis). Heidegger asks how is this answer arrived at? What is it in perception that appears to link it to knowledge, and by extension to truth?
For the Greeks, the becoming perceived of something, in perception, is the same as phantasia. This is what a thing appears as, what it shows itself as, its appearance. Heidegger makes the point that appearance should not be understood as illusion, what something seems like. Even so it will be seen that seeming returns at the end of Heidegger’s account of the Theaetetus as a feature of hiddenness i.e. untruth.
Returning to phantasia as appearance; that which we perceive in a perception is there in a state of being perceived, which we take for what it presents itself as. Heidegger gives an example: “the moon itself that appears in the sky, that presents itself and is present; this is something that shows itself.” The moon shows itself as being present, which we take for what it shows itself as, the moon. Therefore aisthesis has a double meaning relating to the perceived in its perceivedness, and our perception in which perceivedness occurs. Theaetetus’ thesis is that knowledge, as truth, is this perceivedness of what is seen. That which we perceive, in a perception, is there before us as something that shows itself as present, as “a kind of unhiddenness,” i.e. as being.
Theaetetus equates perception with truth, and therefore being, because what we have in a perception, i.e. the thing in its appearance, appears as “the most immediate mode of the unhiddenness of something…the most tangible truth.”
Yet it is open to question that what becomes manifest in this relationship, between what shows itself and perception, is the unhiddenness of beings as aletheia. For this to be the case our “perceptual comportments,” seeing, hearing etc, through which we have a perception, must “have a relationship to beings as such.” To test this claim the analysis next focuses on the essence of perception. Asking first whether or not a perceptual comportment “can bring itself into a relationship to beings as beings, such that the unhiddenness of beings is given in the perceivedness occurring in such a comportment.” (121)