Cavett's argument is really two-fold. In the first place, he obviously regards Santorum as deranged or at least deviant. Eight kids? Professing faithfulness to his church's teaching? Not looking like a president? Wearing sweater-vests? These are all things he cites as problems with Santorum, and by the time he is done with all of that Cavett ought to be out of a job, because - well, he admits himself that we all know making fun of a person's appearance is rude. But having the opinions he does, for Cavett homeschooling is clearly just a stick to beat Santorum with, or maybe Santorum is a stick to beat homeschooling with, because to Cavett the only conceivably legitimate teaching is that done by a professional. After all, he says,
Teaching is an art and a profession requiring years of training. Where did the idea come from that anybody can do it? How many parents can intuit how to do it?
There is a basic flaw here in his chain of reasoning. Certainly if teaching were the demanding, specialized thing he makes it out to be, then he might have a point. Unfortunately for his case, it is not. To take his claim back to front, rather than asking how parents can figure out how to teach it would be more accurate to ask how many parents do not teach their children anything. Ignoring school for the moment, who taught you to read, to rake leaves, to change a tire, to clean your room, to share with others, to use the right fork? Who coached your first soccer game, went out driving with you for your permit, showed you how to do laundry, cook pasta, take care of a dog (or the lawnmower), manage a checking account? (I have looked: that last definitely was not your math book these days.) Of course mom and dad do not usually have the expertise to teach all the nuanced multiplicity of disciplines the modern education wants to demand, but the old standbys: reading, writing, and arithmetic? They know those, and they can teach them. Teaching is a human thing.
Of course I am not saying they always do teach them. I have dealt with plenty of homeschooled students who cannot figure out a simple proportion and get lost in decimals. On the other hand, there are a fair number of students from a "regular" school who do no better. I would say that the craze for online classes seems to have produced some troubling results - but no more troubling than, say, the numbers of students who have trouble reading because they were faddishly protected from phonics. (And I would note, while I am at it, that online classes, like most things, can be done well or badly.)
The obvious retort to my above description is to ask, "What about dealing with all kinds of kids?" or, "What about the tricky subjects?" On the first point, I would have been inclined to admit that classroom management (incidentally not something pertinent to homeschooling) might be a carefully learned professional skill, were it not for the curious case that I find myself a teacher, and I believe a reasonably good one, having taken exactly zero classes or training sessions in any sort of educationism. I had what we call a liberal education, which is to say some of everything with a lot of books in different languages; I then took my bachelor's degree in a subject - mathematics, for the curious - and after some of the usual post-collegiate adventures, I have settled down to teach that subject to highschool students, with what seems to me very little difficulty fitting in. For those keeping score at home, let me sum up: I was a homeschooled student who have fit comfortably into the school environment in the profession Cavett considers so exclusive with absolutely no training. For those more inclined to the economic argument, there is a reason teachers' salaries are low (at least out on the market): almost anybody can do it.
As to the second: see above what I said about doing things well or badly. The conscientious homeschooler - and even Cavett would have to admit that whatever else Santorum is, he is conscientious - finds a tutor, or a class to share, or works cooperatively with others. And even if they did not - if the homeschooled child's education was limited to reading, writing, basic arithmetic, and nothing else at all, I posit that while limited it would still be sufficient to get along. How many of us really use a foreign language even monthly, or need to know the phylogenetic origin of the potatoes we eat?
The funny thing is, Cavett is forced in the end to admit that there are times homeschooling is a responsible choice, thus making this blogpost mostly irrelevant beyond pointing out that it might be responsible more often than he thinks. But he is absolutely appalled at homeschooling, in general - the truth comes out! - not really because of academic or even social concerns so much as such as for worldview reasons. Santorum's (or other) homeschooled children might not learn the definite truth that the universe has been around forever and life accidentally happened somehow, or that we should respect all other cultures (but not our own), or that the woman over there is "him" because she, I mean he, said so. These people have to learn that the logic stuff they are all so fond of only extends so far, and definitely not to reality!