Also, several of your examples aren’t that convincing to me. Did we need to discover the effect of oxytocin and vasopressin on cooperation to decide that it is better to cooperate? No, though it’s a nice plus from a scientific perspective.
Actually, I think that this is one of my stronger examples. The discovery of neuropeptides that specifically induce bonding is a strong argument against the Hobbesian view of human nature. And there are a lot of details that came out of that line of research that shed light on fine details of human nature. For example, oxytocin promotes bonding, but also the out-of-group exclusion that underlies xenophobia and racism. A different number of oxytocin receptors may cause some people to be monogamous and others to be promiscuous. The effect of oxytocin on the ultimatum game reveals that it is involved in generosity and altruistic punishment, two things that have a direct impact on ethics.
The beneficial effects of cannabis aren’t a discovery of neuroscience, but of medicine and psychology. And neuroscience still tells us little about schizophrenia and paranoia, but we have treated them as diseases for a long time, on the basis of psychological research.
Neuroscience, and not medicine or psychology, discovered the three cannabinoid receptors CB1, CB2 and GPR55. It found that THC is a partial agonist at CB1 and that cannabidiol (CBD) acts on CB2 and GPR55. It went on to find that activating GPR55 with CBD can cure childhood epilepsy, by unraveling the mechanism connecting GPR55 with the Nav1.1 sodium channel. And the research is just getting started.
Psychology can do nothing to cure schizophrenia and it can only treat some of the symptoms of paranoia. Hopefully, one day neuroscience will find the cure to these diseases. So far, it has come out with some drugs that can alleviate them.
I followed your link to your article criticizing Patricia Churchland and I agree with you that her excessive reductionism is unwarranted. “Eliminationism” sounds silly. I am an emergentist, so I agree that phenomena have to be understood at their level. Still, one of the strengths of science is how it can provide a comprehensive explanation of the world by linking the levels of physics, chemistry, biochemistry, physiology and neuroscience. And, in practice, these are getting more integrated. Each experiment I do in my lab links the molecular, the cellular and the whole animal levels.
New techniques like optogenetics link physics with chemistry and physiology to produce changes in animal behavior and, pretty soon, human behavior. It is quite amazing that drugs like LSD can induce spiritual experiences, but when we start manipulating individual neurons using optogenetics and DREADD our ability to change the human mind would increase enormously. And that will have enormous ethical implications, both good and bad.