Some philosophers of mind claim that non-reductionist physicalist theories of the mind cannot explain the causal interaction between consciousness and the physical world. The problem is about explaining how consciousness, which cannot be reduced to physical processes, interacts with the physical world without violating the laws of physics. John Searle claims to have solved the problem of mental causation in his theory of mind, which he calls Biological Naturalism, exhibiting a non-reductionist attitude. In this study, I aim to evaluate Searle's solution to the problem of mental causation. For this purpose, I will first touch on mental causation and how it is understood. Then, I will outline the problem and address the specific criticisms against non-reductionist physicalists. Finally, considering these criticisms, I will show under what conditions Searle's solution to the problem of mental causation can be accepted as correct.