Most psychologists agree that all the relevant differences in people's personalities can be reduced to the Big Five traits, and they are right about that of course. We all agree on that, and we must agree on that if we believe that Socionics is a correct theory.
All these theories describe the same reality, the same empirical phenomena, only using different names and explanations for what we all can observe. The Big Five is the most commonly accepted model, but its five basic traits are nothing but the four dimensions in Socionics, MBTT, and Keirsey with one dimension added -- neuroticism. Conscientiousness is the same phenomenon as the J/P dichotomy, which is the same as the difference between rational and irrational types in Socionics and Jung.
These fundamental human traits are not tied to any specific theory, because they can all be observed by everyone without any previous theoretical knowledge, and they also have been observed and described long, long before Jung came up with his idea that there are eight basic psychological types. Jung was not the first typologist, and Socionics is certainly not unique when it comes to how to understand the four dimensions.
If Socionics would not describe the four dimensions of the 16 types the same way that they are correctly described by others who have been observing the same reality, Socionics would be a an incorrect theory on the types. But that does not seem to be the case. Socionics describes the 16 types in roughly the same way as everyone else -- except for the fact that some misguided people on this forum have not realized it and instead invented their own private version of Socionics that contradicts what "official" Socionics says about the types.
The most fundamental and generally valid definition of any type in any model -- including Socionics -- is in relation to the four (or five) basic dimensions (scales, dichotomies). If anyone, at any time or any place, would ever find that his or her presumed type in Socionics contradicts his or her presumed typed as defined by the four dichotomies, then we know for certain that he or she has been mistyped. Your type in Socionics is necessarily defined by the four dimensions.