Nature itself, he says, provides examples of how the immaterial interacts with the material:
Nature is pervaded by immaterial forms like chirality that determine the properties of matter. This interaction is well recognized in science. It is in this sense that spirit and matter can and do interact.
A simple example from chemistry will help: It is the property of certain things to exist as mirror images of each other; my right and left hand are an obvious example. From the standpoint of matter, my hands are identical. They have the same bones, muscles and nerves. What makes them different is their form. My right hand is a mirror image of my left hand. That is, it is the form alone—the organization of my hand—that makes the difference, rather than the matter of which my hand (right or left) is composed. Michael Egnor, “How can mind interact with matter?” at Mind Matters News
More by Michael Egnor on the interactions of mind and body:
Four researchers whose work sheds light on the reality of the mind The brain can be cut in half, but the intellect and will cannot, says Michael Egnor. The intellect and will are metaphysically simple.
Atheist psychiatrist misunderstands evidence for an immaterial mind Patients with massive brain damage were shown to have a mental life
and
A materialist neuroscientist continues the argument with himself. On the topic of “intellectual seizures,” he seems committed to both points of view
How can mind interact with matter?