Thomism is the unlikely child of Aristotelian science and Catholic theology birthed by Thomas Aquinas in the thirteenth Century. Thomistic philosophers always sound smart when they talk, and they should because they’ve had a thousand years to develop their act. In my experience, professional Thomist philosophers are careful and clear in their expositions, making sure they they don’t use a difficult concept without first laying it out in a way that modern readers can grasp, but Thomist philosophy in internet comment forums tends to be offered in ways that seem abrupt, impatient, and often scornful.
Thomism, because of its Aristotelian roots, is not very compatible with the modern world view and modern way of thinking. Moderns analyze the world into physical parts; Aristotelians analyze the world into conceptual parts. Moderns view the process of observation as gathering of data to be processed through some (mysterious and still not explained) logical process of induction; Aristotelians view the process of observation as one of grasping the nature of what is observed. Moderns view a definition as a mere convention; Aristotelians view a definition as significant knowledge.
These radical differences in thought make any communication between moderns and Thomists hazardous and prone to misunderstanding. Thomists are not the only ones who have this problem. Hegelians, Marxists, and Randians (who impudently call themselves objectivists) have a similar problem. That’s why these are the people, along with Thomists, that you most frequently see on the internet acting like they can just spout a bit of obscure doctrine and settle a complex issue; it’s because, I conjecture, in their world the obscure doctrine DOES settle the issue. But that doesn’t make it a suitable reply for someone who does not share their vocabulary, their assumptions, or their world view.
I’ve seen two recent incidents of Thomists (or at any rate, philosophically-minded Catholics) behaving this way. One of these incidents prompted me to write Sex and Substance–a parallel between Social Justice and Catholicism; the other involved the claim that the problem of whether God has the capacity to do evil can be solved by saying that God cannot be distinguished from the property of being good. My interest here is in the abstract argument, not the specific conversation, so I’ll quote from the Stanford Encyclopedia of Philosophy:
God is simple in that God transcends every form of complexity and composition familiar to the discursive intellect…. There is also no real distinction between God as subject of his attributes and his attributes. God is thus in some sense identical to each of his attributes, which implies that each attribute is identical to every other one. God is omniscient, then, not in virtue of instantiating or exemplifying omniscience — which would imply a real distinction between God and the property of omniscience — but by being omniscience. And the same holds for each of the divine omni-attributes…
Now, to a modern thinker this is simply nonsense. The article goes on to explain how such a thing can make sense, but it takes around 13,000 words to do so–not something that is practical in a blog comment. For my part, although the SEP article was able to make the idea coherent to me, it remains so implausible as barely to be worth discussion.
That is what the Thomist is dealing with when he tries to answer a complex philosophical question with Thomist doctrine. Many people will find the doctrine incoherent, and those that find it coherent will find it extraordinarily implausible. And it is by no means appropriate to react with scorn, impatience, or contempt because they fail to grasp or fail to accept something so foreign to their way of thinking.
So why offer the answer at all? You wouldn’t try to persuade an atheist to believe in God by referring to the authority of scripture; you wouldn’t try to persuade a Russian (in Russia) to allow free speech on the basis of the US Constitution. When you are genuinely trying to persuade someone, you start with premises that they will understand and find acceptable. Thomist definitions often do not meet those criteria.