Come to think of it, even if we could demonstrate to a progressive that his ideas are bereft of common sense, it wouldn't dissuade him from holding them. I say this because we see how easily the left dismisses even mathematics as racist, i.e., as a tool of the patriarchy to oppress peoples of color (and remember, crazy travels at the speed of the left, such that today's absurdity is tomorrow's orthodoxy).
Now, mathematics must literally be the least racist thing in all of existence, being that it deals only with abstract quantities, not concrete qualities. And even then, the left is selective in its rejection of numbers. For example, they literally believe that if there is a statistical disparity between the population of a victim group and its representation in this or that field, it is a priori proof of racism.
But you will have noticed that they never apply the standard consistently. If they are vastly over-represented in a desirable field -- as, for example, blacks in the NBA -- then that's fine. Obviously it is nonsensical to make an appeal to math based upon personal interest, but this hardly stops them. In his Discrimination and Disparities, Thomas Sowell completely dismantles the idea that abstract statistical disparities are a consequence of real racism, but I doubt that any mainstream outfit would even review the book -- any more than, say, a Jewish publication is going to review the catechism of the Catholic Church.
Which goes to the essential point: the progressive left is a religion, not a belief system grounded in fact, logic, human nature, or common sense. And even then, to say it is a religion can't be correct, as genuine religion is rooted in a transcendent reality that is ruled out by the leftist metaphysics.
But this makes the left not less, but more dangerous, because it is animated by religious passion, energy, and impulse, but without religious tradition, proscription, and constraint. This is precisely what makes them so cluelessly sanctimonious and self-confident in their beliefs: like little Greta Thunberg says, those of us who aren't on board with her hysterical fears of climate armageddon are evil. She and her ilk are very much like premodern religious folk who grew up without knowing about the existence of other religions.
In the foreword to Reclaiming Common Sense, Brian Kennedy points out that "For over a century now, there has been a sustained attack on common sense," which is to say, "the foundation of the American founding." In fact, I think the attack has always been present, because it is rooted in human nature, more on which as we proceed. But it was certainly mainstreamed and institutionalized a little over a century ago, with the election of Woodrow Wilson in 1912. He was the first president to openly disparage our founding principles.
After Wilson the disparagement went underground, as Democrat politicians learned to conceal their contempt for the American founding and for the average American. Only in the last decade or so is it once again openly celebrated, such that you can't be a Democrat candidate for the presidency unless you enthusiastically embrace the identity politics that is utterly antithetical to our founding principles, i.e., to common sense. As recently as 2012, an Obama had to pretend to believe in traditional marriage, or in the importance of fathers. No more. That's ancient history, before the Great Awokening.
Is it common sense to say that human beings are intrinsically capable of self-government? Cleary not. Consider just Venezuela, which voted for its own demise. No, the possibility -- and desirability! -- of self-government must be rooted in a deeper principle than mere "democracy." Affirming a belief in democracy is totally nonsensical unless you pay attention to the principles that permit it to function, AKA common sense. No founder ever imagined that self-government was possible in a population of individuals who couldn't govern themselves.
Really, this is just an extension of the principle that duties and responsibilities are prior to rights. Note that we do not merely say they are reciprocal, because if this were the case, conferring the right would create the responsibility.
And this is precisely the problem in the rights-obsessed left. The rights embraced by the founders are rooted in nature and nature's God, i.e., in human nature and its author. These rights are not, and cannot be, created by the state, but are prior to it. And each one is attached to an antecedent responsibility, if only because one would have to be a fool to give unalienable rights to a fundamentally irresponsible being! That would be a recipe for tyranny and chaos, not ordered liberty.
Conversely, consider, say, the "right to abortion." Supposing it is a right, what is the corresponding -- and antecedent -- responsibility? Crickets. Likewise, suppose you have a property right in other human beings. What's the antecedent duty? In other word, if you are free and your slave isn't, what is the principle that renders this arrangement just?
Does common sense have a specific content, or is it more of an attitude or approach to life? Yes and no. It embodies certain principles that cannot not be, but also involves prudence, or a practical wisdom that cannot be reduced to an abstract rule. For example, being honest is fine in principle, but not when the Nazi asks if any Jews are hiding in your house. Clearly there must be an antecedent hierarchy of values, such that protecting human life is the higher principle.
At this very moment, we are living through a prudential values dilemma: what is more important, the principle that we should never enlist the aid of a foreign country to investigate the corruption of a presidential candidate, or the principle that no one is above the law? To believe the former is to say that a man can be exonerated of any crime so long as he runs for president after he commits it. Does that make any sense?
Yes, it does. To the left. Which again highlights what was said above in the second paragraph. If a person arrives at a belief without using common sense, you can't use common sense to talk him out of it.
The End for now. I gotta get some work done...