Being a medical student, I have to agree with most of what you said. However, I also know that the mind-body connection is extremely complex, and that every interaction that happens inside of our bodies every second involves thousands of chemicals, at a minimum.

We try to symplify things by refering to the outward results of these interactions on a more long-term scale.

Also, everything we experience happens as a result of all of these interactions, combined with whatever is happening external to our bodies, and how we perceive that, etc.

However, when you put it all together, it seems to me that the whole is still greater than the sum of the parts.