I've thought about this for a while and others have as well. I believe that for socionics, it fails to make any sense, if you just look at psychology. You have to connect it to biology for it to be even credible. Just think about it, our personalities are molded because of the way our brain is developed. If one area in the brain is more developed than another than your more likely to be a thinker rather than a feeler. This correlates with every other function as well. Without biology, socionics is a useless imaginary theory.