Of these theorems, subjective value proves to be the most difficult for Thomists. According to Aquinas, every being is good in himself as a transcendental property. Each being stands in close relation to an objective moral order, where moral values are not defined in relation to subjective human preferences, but in view of human nature as such and its ultimate end, God. But this seems to contradict praxeologically-based subjective value theory. However, if concepts are clearly defined and articulated, no such contradiction will result.
Valuation occurs when a person chooses between option a and option b .
Valuing necessarily reflects the internal scale of preferences of the acting person. If John desires good x, and x1 is a means to achieve it, x1 has a subjective value, that is to say, is valuable to John, given his subjective preferences. John could be mistaken regarding his preferences, or ends, which includes the possibility of moral error, or erroneous with respect to the real capacity of x1 to achieve x. But as we have already mentioned, error is a natural aspect of human rationality. But these meanings, however complementary, remain distinct.