The impressive connections between mental processes such as perception, learning, memory, and
reading and specific brain processes are evidence for the identification of mind and brain only if
brain changes cause mental changes. But perhaps there is only correlation here rather than causation.
The fact that ice cream consumption and drowning frequency are correlated does not show that one
causes the other, as they have a common cause in high temperatures. A dualist could argue that all the
empirical studies described above merely show that brain processes correlate with mental ones
without brain's being the exclusive cause of mind. In scientific reasoning, the best way to show
causation rather than mere correlation is to introduce an intervention, showing that manipulating one
factor leads to a change in another factor. In psychology and neuroscience, there are both technical
and ethical reasons why it is often hard to show that manipulating the brain can produce mental
changes.