> OP is incorrect that psychology is not a science.

Pretend to be a scientist and post your evidence. Here's mine -- the director of the NIMH has recently ruled (http://www.nimh.nih.gov/about/director/2013/transforming-dia...) that the DSM (psychology's "bible") may no longer be used as the basis of scientific research proposals, for the simple reason that it has no scientific content. The director went on to say:

"The goal of this new manual, as with all previous editions, is to provide a common language for describing psychopathology. While DSM has been described as a “Bible” for the field, it is, at best, a dictionary, creating a set of labels and defining each. The strength of each of the editions of DSM has been “reliability” – each edition has ensured that clinicians use the same terms in the same ways. The weakness is its lack of validity."

"Unlike our definitions of ischemic heart disease, lymphoma, or AIDS, the DSM diagnoses are based on a consensus about clusters of clinical symptoms, not any objective laboratory measure. In the rest of medicine, this would be equivalent to creating diagnostic systems based on the nature of chest pain or the quality of fever. Indeed, symptom-based diagnosis, once common in other areas of medicine, has been largely replaced in the past half century as we have understood that symptoms alone rarely indicate the best choice of treatment. Patients with mental disorders deserve better." [emphasis added]

There is often an embarrassing degree of self-reference in discussions where psychologists try to claim that psychology is a science. The defenders invariably see no need to produce evidence for their claim, as though evidence is irrelevant in a discussion of science. And for a typical psychologist, saying psychology is a science is expected to end a conversation, whereas for a scientist, that claim can only begin a conversation in which evidence rules.

> Next up we have this whole notion of falsifiability. It's a red herring.

Only if science isn't defined as it is in the law -- which it is. Science-defining laws are on the books to keep Creationism out of public school classrooms, and while crafting those laws with the assistance of expert witnesses, guess which non-negotiable criterion always appears in the final ruling? Falsifiability.

Here is one such ruling (http://www.talkorigins.org/faqs/mclean-v-arkansas.html) -- science must have these properties:

1. It is guided by natural law;

2. It has to be explanatory by reference to natural law;

3. It is testable against the empirical world;

4. Its conclusions are tentative, i.e. are not necessarily the final word; and

5. It is falsifiable.

I bring up this law to make perfectly clear that falsifiability, empirical evidence, and the other standard requirements for science, are only red herrings to people who think they can define science any way they please. For a scientist, obviously this kind of argument is unnecessary -- they already understand what science requires.

> What is correct is that experimental designs are more or less not possible in behavioural psychology.

Wait, what? Because one cannot design reliable experiments in psychology, therefore psychology is scientific? On what basis -- that real science is too difficult?

> This could be OP's second point of confusion.

The only confusion is yours.