Physical objects are compounds of matter and form, as stated by Aristotle in his hylomorphism theory. The concept of “form” in this theory refers to physical structures or organizational structures. However, mental processes are not of this kind, they do not change physical arrangement of neurons, but change their states. To cover all natural processes hylomorphism should acknowledge differences between three kinds of forms: Form as physical structure, form as function resulting from organization and interactions between constituent parts, and dynamical (...) form as state transitions that change functions of structures without changing their physical organization. Dynamical forms, patterns of energy activation that change the flow of information without changing the structure of matter, are the key to understand minds of rational animals. (shrink)