 The complexity underlying Plato’s theory of the Forms as it is first applied in the Phaedo is easily overlooked, because the Phaedo initially suggests that that recollection is no more than the grasping of concepts – the concept of ‘exact equality in size’, for example, is prompted by the perception of more or less equal-seeming sticks and stones (74a–e). Not only that, the same is suggested by the list through which Socrates first introduces the Forms, 65d–e: “Do we say that there is such a thing as the Just itself or not? And the Beautiful, and the Good? […] I am speaking of all things such as Tallness, Health, Strength, and in a word, the reality of all other things, that which each of them essentially is.” Such an appeal to recollection leaves a lot to be desired. How does it work? How can one ensure that one’s intuitive grasp of these natures is correct? That the ‘recollection’ of isolated ideal objects is not the whole story emerges later in the Phaedo when Socrates presents a ‘simple minded hypothesis’ of the Forms as a way to avoid his difficulties with the causes of generation and destruction (Phd. 99d–100e). The hypothesis he starts out with seems simpleminded indeed, because it consists of nothing more than the assumption that everything is what it is by participating in the corresponding Form. But it soon turns out that more is at stake than that simple postulate. First, the hypothesis of each respective Form is to be tested by looking at the compatibility of its consequences. Second, the hypothesis itself is to be secured by higher hypotheses, until some satisfactory starting point is attained. Unfortunately, Socrates explains neither the kinds of consequences nor of the kind of ‘satisfactory highest principle’ he has in mind, but confines himself to the demand for an orderly procedure. The distinctions that Socrates subsequently introduces in preparation of his last proof of the immortality of the soul seem, however, to provide some information about the procedure in question (103d–107b). Socrates first introduces the distinction between essential and non-essential attributes. This distinction is then applied to the soul: because it always causes life in whatever it occupies, it must have life as its essential property, which it cannot lose. The soul is therefore incompatible with death and must be ‘deathless’ = immortal. The viability of this argument, stripped here to its bare bones, need not engage us. The procedure shows, at any rate, that Plato resorts to relations between Forms here. The essential tie between the soul and life is clearly not open to sense-perception; instead, understanding this tie takes a good deal of reflection on what it means to be, and to have a soul. To admirers of a two-world metaphysics, it may come as a disappointment that in Plato, recollection should consist in no more than the uncovering of such relationships. But this agrees well with the fact that with the exception of such concepts of perfection as ‘the Good’ and ‘the Beautiful’, all of Plato’s examples in the Phaedo are quite pedestrian. Not only does he confine himself to concepts like ‘tallness’, ‘health’, ‘strength’ and ‘the equal as such’, – thereby invoking objects that are familiar from every-day experience; – but he also treats the fact that knowledge of their nature cannot be derived from sense-perception alone as sufficient evidence for the existence of the respective Forms, as he shows in the case of equal-looking sticks and stones.