Until very recently (mid 90's) many psychological phenomena were explained by childhood experiences, in line with Freud's psychoanalytical theory. Many of these have since been disproved. One criteria I have for trustworthiness of a scientific discipline is that of stability. If the previous theory has been found to be very wrong, very recently, then I am cautious to trust again.
Specifically note that his theory, although debunked, still lives on in philosophy and literature analysis. This "stickiness", that people refuse to give up the theory when proven wrong is additionally a bad sign.
People really like to trash Freud, but you have to put him into context. Before Freud, we had a few branches of psychology: philosophical psychology in England arguing about empiricism vs. nativism, Wundtian psychology in Germany sitting around asking very specific questions that they answered using introspection, and in the States we had the very first blossoming of the behaviorism that would dominate psychology in the States until the '60s[0]. Some of these approaches had a concept of the subconscious, but they all viewed it as a static warehouse for previous experience, and very few people thought about it in a serious way.
Freud's major contribution to psychology was that we actually have a dynamic subconscious that profoundly affects how we live our lives. This aspect of his theory has become so ingrained in our culture that it's hard to imagine the world before Freud. Also, that aspect of his theory has held up over the years.
Also, he got a number of things correct: many of his coping mechanisms have strong empirical support, for instance.
Freud was wrong in detail, but his overarching approach changed psychology for the better.
[0] Yes, I know this "history" is a vast oversimplification.
The concept of subconscious is much older than Freud, it was a staple of the romantics. Freud proposed a specific structure theory of the subconscious centred around the Oedipus complex. That specific theory is indefensible.
Psychology is a very broad area and it's not fair to judge it based upon Dr. Phil style counselling or literary criticism.
The psychologists I've worked with design experiments to attempt to determine fundamental mental capabilities in terms of perception, memory, spatial reasoning, etc. and how this can be applied to design safe and effective user interfaces, in particular for safety critical systems like aircraft.
Sure, the models they develop are likely just useful approximations, but it seems that models at the neuron level would be too unwieldy for these sorts of questions anyway.
At least in the US, up until the 50's/60's behaviorism (which at least claims to be based in observation) was a dominant school of thought in psychology.
"Empiricism" does not usually refer to taking measurements (which seems to be what you have in mind); it is a theory of epistemology which holds that knowledge is primarily experiential. (It just happens that many psychologists are causal empiricists, but it has nothing per se to do with their love of measurement.)
