Hacker is an excellent philosopher and a very clear writer. He starts from broad categories to look at human nature and what it makes sense to say of the nature of sentient animals, insentient animals, and inanimate things.
The main relevant chapters are:
1. "Agents and Actors",
2. "Teleological Explanation", and
3. "Reasons and Explanation of Human Action".
His main point is that many "unanswerable" questions in neuroscience and behavioral science are simply nonsensical because they play with conceptual confusions.
I would also highly recommend his sequel book "The Intellectual Powers: A Study of Human Nature".