Socrates explains the nature of his ‘second-best’ course: it consists in approaching reality not by the ‘direct’ method of sense-perception and observation, but by the ‘indirect’ method of propositions (λόγοι): more specifically, it is a method of hypothesis, that is to say the establishment of some proposition through deduction from a hypothesis, or proposition assumed to be true, followed (if need be) by a defence of this hypothesis through deduction from some ‘higher’ one. The method is exemplified by a proposal to deduce the immortality of the soul from the hypothesis (which will need no defence, since all present accept it) of the existence of the Forms. The relevance of this to the inquiry, which in the preceding section Socrates had declared to be necessary, into the cause of coming-to-be and perishing, is now made clear: the Forms are the sole and sufficient causes, and are adequate to resolve all the doubts and problems which Socrates had encountered in his early scientific inquiries.

'Well, at that point, when I had wearied of my investigations, I felt that I must be careful not to meet the fate which befalls those who observe and investigate an eclipse of the sun; sometimes, I believe, they ruin their eyesight, unless they look at its image in water or some other medium.