Simplify the following text for a Grade 9 native English-speaking person.
Original: He holds the position of State of New Jersey Professor of Philosophy at Rutgers University and is the author of many works in the fields of philosophy of mind and cognitive science , in which he has laid the groundwork for the modularity of mind and the language of thought hypotheses , among other ideas .
Simplified: He mostly works on the philosophy of mind and cognitive science , both of which are concerned with how the mind works .