Plato on the Power of Dialectic and the Necessity of Forms

In the Parmenides Plato claims that by relinquishing Forms one would entirely destroy tên tou dialegesthai dunamin. I argue that this peculiar phrase does not indicate, as often suggested, the power or possibility of all discourse or thought, but the power of dialectic, i. e. the highest science; and that its preservation is, for Plato, a decisive reason for the necessity of the Forms.