system
Given the following post, respond as if you're commenting on Reddit:
human
CMV: Because all human thoughts, behaviors, and emotions can be reduced to chemicals which biologists and chemists can study, the field of psychology is unnecessary.

I don't deny that psychological scientists have made many important and useful contributions to society. And I'm not as wedded to the idea that psychology is unnecessary as the title might suggest. But the "hard science is all that matters" voice inside of me is strong, and I'd like to try and quell it a bit.

So far, a good argument I've heard against my position has to do with the placebo effect. Yes, although the placebo effect can be boiled down to the activation of certain chemicals in certain parts of the brain, what actually makes the placebo effect compelling is that it shows how powerful the effects of *thoughts* and *beliefs* can be on the body, a phenomenon a psychologist would probably be better suited to study, rather than a biologist or chemist.
gpt
Perhaps applying the logic to other fields will make you see how ridiculous it is.

0. Since all action posed by economic agents can be reduced to human thoughts, behaviors, and emotions which psychologists can study, the field of economics is unnecessary.
1. Since all human thoughts, behaviors, and emotions can be reduced to chemicals which biologists and chemists can study, the field of psychology is unnecessary.
2. Since all of biology can be reduced to chemical reactions which 
chemists can study, the field of biology is unnecessary. 
3. Since all of chemistry can be reduced to interaction between particles which physicists can study, the field of chemistry is unnecessary. 

While it may be possible to think of economics at the atomic level, it's simply not practical. It's much more efficient and sufficiently effective to opt for econometric analysis instead. The same is true for chemistry, where learning about how organic chemistry is sufficient to proceed to synthesis. Rarely, if ever, does one need to know about the nitty-gritty of physics to produce the right molecule. 

In the case of psychology, one can learn more than enough from clinical trials. In fact, we've yet to figure out enough about the neurochemistry for biologists to derive that information alone. 

Another way to think about it is astrophysics versus particle physics. Fundamentally, everything is about particle physics but that does not render astrophysics useless. When we zoom in or out, we can gain different kinds of knowledge which would have taken a lot more time and effort to figure out using a different methodology. Maybe, one day, particle physics will have reached a point where we could have known everything we know now about astrophysics but meanwhile we'd have been passing on a lot of low-hanging fruits.