Man is a responder, a product of his environment and genetic inheritance. Any behavior which is followed by a positive reinforcement is likely to be repeated. Matter and energy are the ultimate substances of reality. The mental is a manifestation of the material. Seems to have been influenced a great deal by logical positivism.
Truth is that which corresponds to reality as it is perceived by the senses.
To Skinner, this is mainly vision. All the world is a box. No universals, only particulars. The universe is a closed system where every effect has a material cause. Some behavior cannot be traced to physical reinforcement.