  Concerns about the inherent intelligibility, or lack thereof, of the physical world, prompt Plato to propose the doctrine of recollection, i.e., the thesis that our disembodied, immortal souls have seen the Forms prior to their incarceration in the body. If Forms are the (basic) objects of knowledge, and Forms are not in the physical world, then we must have acquired that knowledge at some point prior to our commerce with that world. But metaphysical issues about the simplicity of Forms also affect how we are to conceive of knowledge in these middle period works. If Forms are simple, then it seems that knowledge is intuitive or acquaintance-like: in a non-propositional manner one somehow sees a Form, itself by itself. The central books of the Republic suggest such a picture. On the other hand, the many passages in which Plato declares that in order to know a Form one must be able to give its definition suggest both that Forms are related to one another, e.g., the Form of Human is related to the Forms of Rationality, Bipedality, Animality, the ‘elements of its definition, and that knowledge is propositional or akin to knowledge by description (cf. Gorgias 465a, 501a2–3, Republic 534b). These passages seem to imply that perhaps knowledge is some form of justified true belief. A critical question then is how one obtains the appropriate kind of justification to tie down or convert a belief into knowledge. Plato offers little in the way of detail on this score, but twice he alludes to a method of hypothesis, suggesting both in the Phaedo and Republic that hypotheses and their ultimately being rendered ‘non-hypothetical’ is part of the process by which one comes to know a Form. Thus we have four broad notions to explore in Plato's middle period epistemology: knowledge, belief, recollection and the method of hypothesis.