Hey everyone, I'm new the forum and a psychology student so I thought I would chime into this discussion.
I'm always confused by when people such claims, especially considering there is an abundance of psychology research that can be considered in a true scientific sense, "law" of nature. Few examples that jump to mind is "reinforcement theory", "behavioral momentum" and "Matching law" but there are many more. I'm not sure why psychology is consistently being asked to defend itself as a science or why people do not believe it makes the same level of prediction as other sciences. To me it seems like anyone who has been reading up on and studying scientific psychology knows there have been incredible advances in the science and it is much richer and deeper than what the public perception seems to be.
I'm really confused by this statement, could you clarify on what you mean? The experiments I read about and conduct are not based on social theories but based on previous experimental research, much of it done with non-human animals. I'm not sure what you mean by least offensive to mythology or old religion?
Isn't this a bit unfair considering the nature psychological disorders don't lend themselves to "definitive" tests? It's not as easy as giving taking blood or other samples from a patient. Yes psychological disorders are complex and that's why it requires complex science to understand it, it's not as easy as simplifying it into definitive disorders when the state of nature is not that simple. That aside, it seems like your focusing on DSM diagnosis, which I will grant is not nearly as scientific as it should be, partly due to lingering influence of Freudian theories. However, if your talking about more general psychological assessments and tests, there is very strong scientific research to back up these assessments tools. Using anecdotal evidence of how different psychologists would give different diagnosis does not, in my opinion, prove or speak for the field as a whole. I myself have had clients who have had clearly been misdiagnosed but out of negligence of the clinician, not the failing of the scientifically based instruments or procedures.
Why are you using the DSM as a standard for judging the scientific basis for psychology? Unfortunately, the DSM has remained largely based on opinion and not on scientific data (which exists), despite the community of scientists trying to change the DSM. This is a problem for sure and it's being addressed, just see the uproar over the DSM 5, but it again doesn't speak to the scientific research in psychology. If one wants to claim scientific psychology is not scientific, I think the proper thing to do is to pick the strong research or studies in psychology and in detail describe why it's not scientific.
I'm not sure how comprehensive of a history you were trying to provide for psychology but the above doesn't even cover 1% of what's happened in psychology. The implication that chemicals can be involved in mental disorders was a conceptual leap forward but there were far greater advances in the field towards scientific psychology. Even in terms of looking at neurobehavioral evidence from a biological perspective, we know that chemicals are involved in every human behavior so it's pretty useless statement with current research. However, both psychological and biological research fields have been developing more complex models of bio-chemical processes that underly psychological and behavioral processes. I think Robert Sapolsky is a very good example of this type of research.
As for other developments in the field, I would suggest at starting off by covering B.F. Skinner who pretty much set the stage and argument for how psychology can be a science to modern day work in behavior analysis, cognitive science, and psychophysics as good places to start if your interested in learning about the scientific developments in the field. Also, since the focus seems to be more on mental illness rather than scientific psychology in general, I would suggest reading up on developmental psychopathology research which is a very well solid area of scientific research on psychopathology (mental illness).
Psychologists do that too and even though I'm not sure what your intention is in bringing this up, I assume it's a criticism of a sort. I would again like to point out that the situation is different in psychological care, especially in cases where clients are suicidal or at risk for harm towards others among other situations that require "overturning patient rights". Anyways, I see this as a topic of bio/medical ethics rather than a failing of psychiatry/psychology.