I don’t honestly know the answer to this question. I do know there are a lot of workbooks out there whose very presence makes me feel like I do need to teach critical thinking. I don’t remember ever being taught critical thinking skills myself except in a very informal way by my mother who taught me to do the sort of logic puzzles found in crossword books. I suppose before I took SATs I was given some introduction to analogies but I still don’t remember there being extensive instruction in them (or in any other part of the test taking for that matter).
I guess the question is two-fold: are these skills one needs? and do we need to teach them? I do think logical skills are good to have, at least to some degree. I also think that we need to distinguish between what is usually taught in all those workbooks, things like logic puzzles, Venn diagrams, and analogies, and thinking critically about a piece of literature. We tend to lump both together under the heading “critical thinking” but it seems to me they are very different things.
In terms of the former, I do think a course in logic at some point could be useful. Some of what falls under this heading may arise in math class. I am thinking here particularly of geometry with its proofs and theorems.This sort of thinking, being able to reason that if A and B are true then C cannot be true, seems like it could be very useful in certain professions, particularly those that are themselves more logical. And with the number of people who have to use computers with their need for clear step-by-step programming, it would seem that being able to think in such ways could be very helpful. Even reading the news often requires one, if we wish to truly find the truth, to be critical. Too many news stories report the results of scientific studies only to then draw conclusions which those studies do not warrant. So this kind of critical thinking is something I value. I am not sure that the many workbooks available to aid in this logical thinking do much to further the cause, however.
There is also a value to being able to convince others, to see their presuppositions or where their arguments may be weak. And also to be able to see the weaknesses in one’s own argument so as to better shore it up. This is a more rhetorical kind of logic but it seems like something we should all know a bit of. Though I don’t follow the classical model of education, I do think this is the sort fo thing that could be taught in later years as one class. Of course, planting seeds as one goes along by pointing out fallacies and bad reasoning when one encounters them would lay a good groundwork.
Lastly, we come what might properly be called literary criticism. This is at least a slightly different arena than the above types of critical thinking though the two often seem to be lumped together when we discuss “critical thinking.” Literary criticism is inherently destructive in that it takes a text and dissects it. My own field of study was the Old Testament, and so I can speak best on biblical criticism. I do think there is some profit in textual and literary criticism of the Bible. They have produced some useful insights which can help us to understand the biblical books. But they have also engendered a lot of problems. They tend to shred the text and cause the critics themselves and those who listen too much to them to lose faith and respect for the text. When we take apart a text, we place ourselves over it and we no longer appreciate the beauty of the whole nor do we put ourselves under its authority. Of course not all texts have the authority of the biblical text. But they are still there for us to learn from what we will, to form relationships with as Charlotte Mason would say. And when we dissect them, we can no longer see the big picture. We take a living book and turn it into a specimen, like the frog in a biology class. Charlotte says that we should save critical studies to a late date and that even then, they need not necessarily be taught but that they will arise naturally from a thinking mind:
“We miss the general principle that critical studies are out of place until the mind is so ‘thoroughly furnished’ with ideas that, of its own accord, it compares and examines critically.” [Formation of Character, p. 187]
So I guess my own conclusion is that while I do value some forms of critical thinking, I am not sure that workbooks are the way to teach it.