Inherence refers to Empedocles' idea that the qualities of matter come from the relative proportions of each of the four elements entering into a thing.
That Plato accepted (or at least did not reject) Empedocles' claim can be seen in the Timaeus.
However, Plato also applied it to cover the presence of form in matter.
Matter, on the other hand is passive, being a mere possibility that the forms bring to life.
Aristotle clearly accepted Empedocles' claim,[1] but he rejected Plato's idea of the forms.