The Six Books of Proclus on the Theology of Plato, Volume 2

For if that which produces, gives subsistence to similars prior to dissimilars, the similitude derived from the producing causes will give subsistence to the things produced. For similars are rendered similar through similitude, and not through dissimilitude. If, therefore, progression in its diminution preserves a [certain] sameness of that which is generated with that which generates, and exhibits that which is posterior to the generator such in a secondary degree, as the generator is primarily, it will have its subsistence through similitude.