A behavioral activity. They don't have intuitions, feelings, phenomenology. There are limits on our self-knowledge which will prevent us from creating a thinking computer. Practical obstacles may be insurmountable. But with better science and technology, maybe.
All matter exhibits mind in different aspects and degrees.
Machines will never be self-conscious. But since Jones can do A, he can't be a realization of a Turing Machine. Provable limitations aren't limitations on what can be done heuristically with high reliability. All computer programs are algorithms. There is no feasible algorithm for checkmate in chess.