Thomism is not a philosophy of common sense. One cannot point to a single distinct tenet in it as an example of something folksy, commonly believed, or as obviously and inarguably better than its contrary. Just look as some of the tenets in question: the metaphysical primacy of esse, the negation of spiritual matter, the denial of the Ontological Argument, abstracted sense being as the proper object of the human intellect, the rational demonstrability of psychic immortality, analogous predication of positive traits said of God, the single esse of Christ, the status of lying as an intrinsic evil, the primacy of intellection in beatitude, etc. There’s no account of common sense that even allows it to raise questions like this, much less to resolve them.
But I want to make a more general claim, sc. that all philosophy exists in a space that’s been set apart from common sense. To explain this, let me lay out the major philosophical debates in the eras that I know something about:
Major Disputes in:
1.) Ancient Hellenic Philosophy
a.) Whether anything is moving.
b.) Whether we can be certain about something.
c.) Whether we know everything by remembering it from the separate world we lived in before birth.
2.) Medieval Philosophy:
a.) Whether we all think with the same intellect
b.) Whether we need God’s help to know certain things.
c.) Whether abstract ideas exist only in the mind or not.
d.) Whether words like “exists” means the same thing when said of God and creatures.
3.) Modern and Contemporary Philosophy (the part I care about, at least)
a.) Whether one needs a mind to think.
b.) Whether a word is just a kind of symbol.
c.) Whether all arguments can be made in one logic.
d.) Whether time exists, or any objects of thought apart from thought.
None of these questions can be raised by common sense: in fact, to the extent it can address the questions, common sense dismisses them and takes the answer as obvious. This is why philosophy can only exist by putting common sense aside.
But wait, don’t we find the supposed “philosophies of common sense” on the side of the common sense responses to these questions? Of course there’s something moving, common sense tells us, and Aristotle defended just this idea. But there are two problems with this: first, it doesn’t work in all cases. Consider the four disputes in Medieval philosophy. Common sense might have an opinion about (a), but it has nothing to say about (b), and it would probably resolve (c) and (d) in favor of someone like Ockham. But Ockham never gets called a philosopher of common sense. But there is a second, more fundamental problem: common sense of itself would not allow any of the questions to be raised. It won’t let us question whether anything is moving, and so won’t allow us to eventually formulate the distinction between potency and act. Common sense doesn’t side with Aristotle against Parmenides, Plato, or Heraclitus, it brushes all four of them aside as raising silly questions whose answers are obvious.
So let’s drop the idea of common sense in philosophy. It doesn’t seem to do much work outside the practical, everyday world anyway. It might tell up how to avoid falling in wells, but it isn’t of much value in looking at the stars.
Just Thomism 
Gil said,
November 29, 2014 at 11:10 pm
I’d strongly disagree with this. Philosophy without common sense is nonsense and common sense without philosophy is crude and bare. We can know through common sense *that* Parmenides is wrong, for example, but it can still be asked (as Aristotle did) *what* precisely makes him wrong. Adler put this best:
“Aristotle’s thinking began with common sense, but it did not end there. It went much further. It added to and surrounded common sense with insights and understandings that are not common at all. His understanding of things goes deep than ours and sometimes soars higher. It is, in a word, uncommon common sense.”
Common sense is a useful means for keeping ridiculous notions in their proper place whereas philosophy develops common sense into something far more extraordinary. Common sense keeps your foot on the ground and from slipping into wells. Philosophy converts common sense into the fuel that the intellect can use to take off and reach the stars.
Curio said,
November 29, 2014 at 11:36 pm
Well, insofar as it takes common sense as its starting point, Aristotelian-Thomism is much more amenable to common sense than most modern systems. That there is motion, that universals exist in some way, that in the world there is both unity and plurality, that true knowledge is possible and radical skepticism unwarranted are all common sense philosophical claims that a Thomist shares with “Joe on the street”.
cryptonymousbill said,
November 30, 2014 at 10:12 am
Common sense as my pre-philosophical conviction, or what most take to be the case, or the judgment of a plain person – each of these (for all their differences) seems to set the content of our concepts, but insisting that any of them set conditions on comprehension would be like insisting each step in a deduction be seen by the naked eye.
Paul Boire said,
December 1, 2014 at 3:52 pm
Much as I enjoy the good author’s posts which I look forward to receiving, and while usually finding myself being led more deeply into issues and perspectives, the position against common sense seems to go against my common sense. I am, we are, there are other things that exist. While indeed others might follow common sense to deny universals, this same common sense warns others that we cannot deny the reality of universals as essences without refuting the possibility of our own arguments for or against.
We have moral intuitions. A thing cannot be and not be in the same respect at the same time. Indeed we can extrapolate from immediate sense input and conclude we are at the centre of the universe, but there’s a common sense argument against this. I am not a scholar, but an amateur philosopher with that “dangerous thing”, a little knowledge and certainly don’t wish to tivialize the issue, but common sense, “critically examined” seems to me a necessary point of origin. What bedrock might there otherwise exist for our construction of the edifice of essence? That two eyes do not meet in a conical rendering of the visible world, as one might unreflectively assume, and that things are indeed curiouser and curiouser, I grant, but at base , we are in touch with reality or we are not and our foundational capacity for knowledge must perforce rely upon a basic given and basic principles derived from this common sense of things. This is perhaps too simplistic, but it seems analagous to arguments against the value of the import of the senses relying on these same senses.