  The move from the second to the third level crosses the barrier between the visible and the intelligible. One derives ‘images' from the objects of pistis or considers them differently, developing different propositions about what one previously took for granted. Perhaps the scientist describes these images in non-sensible terms, or perhaps he regards the ‘image of triangle’ apart from the particular, determinate angles or lengths that even any image must have—he abstracts away these features, treating the abstract image as applying to all triangles. Or, similarly, the objects of dianoia and nous may be identical: the philosopher thinks about them differently from the scientist. If one assumes that here Forms are first posited, as seems required if we are to understand the descent from nous to secure the Forms, then the objects of dianoia and pistis cannot be the same. For the latter are not Forms but ordinary particulars. We can then explain ‘destroying the hypotheses’ as similar to what, in the Phaedo, was described as finding the higher logoi. The initial strongest hypothesis, i.e., the Theory of Forms, is then rendered non-hypothetical when, and only when, the philosopher has determined which of the many accounts of the general nature of Forms, e.g., immanent vs. transcendent realism, simple versus complex Forms, the nature of the Good and its relation to others forms, is best. The same route would secure the hypotheses of the sciences, i.e., the various interpretations of the objects of the sciences would be eliminated leaving only that one justified by the theory of Forms. The peculiar properties or axioms of the individual sciences would remain the provenance of the scientists. Dialectic or understanding would concern how we are to think about the nature of those properties and the structure of the sciences.