The issue of the present research is the type of relationship between mind and body from the perspective of John Searle. According to Searle, this issue has a relatively simple solution; "biological naturalism" is the name Searle gave to his solution to this issue. According to this theory, mental phenomena such as consciousness, emotions, thoughts, and desires 1. are real things 2. are the result of neurophysiological processes within the brain 3. are within the brain itself and are considered a feature of the brain, and 4. have a kind of causality with respect to the body and cause specific behaviors in humans. The research method is library and documentary in terms of collection, and analytical-rational in terms of judgment. The research findings show that Searle's theory, although it is considered a significant advance compared to some perspectives, is ultimately in the lap of physicalism and is affected by all the problems of physicalism.  Keywords: John Searle, Mind, Mental Phenomena, Biological Naturalism, Dualism, Monism, Neurobiological Processes.