The Receptacle

Plato identifies three kinds of being in the Timaeus. The first is the eternal, intelligible, unchanging — the Forms themselves, accessible only to reason. The second is the imitation of the first: visible, temporal, coming into being and passing away. The third is something entirely different, and it takes most of Chapter 3 to characterise it adequately. It is the space or medium in and through which the second kind exists — the 'nurse' and 'mother' of all becoming.

For the Receptacle to receive all forms, it must itself have none. Plato's analogy is gold: a craftsman who makes many shapes from gold should not describe any of them as the 'real' gold, because the gold's nature is simply to receive whatever form is imposed on it. Similarly, the Receptacle takes on the appearances of fire, water, earth, and air as these appear and disappear within it, but it is none of them. It is the precondition of all appearance, not an appearance itself.

This creates a profound epistemological problem. The Forms are known by reason; sensible things by perception combined with opinion. But the Receptacle is grasped by neither route — it requires what Plato calls 'a kind of spurious reason', a quasi-rational intuition of something that cannot be directly perceived or purely thought. It is 'hardly real' in the sense that it refuses the categories by which we usually fix things as real or unreal.

Interpreters have read the Receptacle as space, as matter, or as a primordial substrate underlying both. It anticipates later philosophical discussions of prime matter, of the void, and of the distinction between form and substrate that would occupy Aristotle. The Receptacle is not nothing — it is eternal and indestructible — but it is as close to nothing as a positive something can be. It is the condition of the possibility of a material world, and that is why it resists description: we are trying to speak about what makes speech about anything else possible.

The Receptacle is introduced in Chapter 3 of the Timaeus. Aristotle criticised the concept in the Physics, arguing that Plato conflated space and matter. The passage was immensely influential in Neoplatonism and in later accounts of hylē (prime matter). The dream-imagery Plato uses — we perceive the Receptacle only 'as in a dream' — became a touchstone for discussions of the limits of human cognition.