Human experience and the
capacities that produce it.
One interesting thing about the concept of mind is that it is a fundamental
metaphysical notion in the sense that it is a
theoretical term and that no
person has direct access to the mind of any other person (ESP
excluded). This is also shown by behaviorism: A philosophy of
psychology that insisted that the only evidence and the only hypotheses that
should be used in the psychological study of human beings referred to their
externally visible behavior.
Behaviorism was somewhat popular under
psychologists from the 1920ies to the 1950ies, mainly supported by
neo-positivism in philosophy, but was based on a mistaken philosophy of
science and flies directly in the face of one's own experiences.
The reason to speak of human experience in the above
definition is based on the fact that human minds are the only minds humans
have experiences of. See Other minds - and the particular trouble here is that no one has the experiences of another.
The concept of the mind is somewhat inbetween the concept of the brain, a material organ that generates experience, while it is - as yet - largely not known how the brain produces conscious experience, and the concept of the soul, a metaphysical notion, that also does not explain much or anything at all, since it is not even tied to any material organ.