Critics of dualism have pointed to neurology and neuroscience as evidence that dualism is misplaced in its approach. When we have a mental thought, for example, imagining myself walking through the front door to my home, a certain part of the brain which correlates to special recognition becomes active. We can clearly see this in MRI scans.
Even something we know intrinsically, like needing a glass of water, has corresponding neurological activity.
Similarly, when I experience pain, there is c-fibre stimulation inside the brain. This suggests that there is a physical process behind each thought and that rather than mental states occupying the realm of the non-physical, they are nothing more than a collection of neurons firing in the brain.