It should never be, like anything else, beyond, above or outside of questioning when it may be shown in error. The delusion that critical reasoning needs no skill or care in its use has done much to misrepresent it in the popular culture, as has the equally delusional notion that it can reveal what is true about contingent matters of fact in the world.
Ill-considered, untrained and incautious reasoning is quite prone to lead to the most egregious of fallacies, and merely being educated and intelligent is not enough to prevent this.
The smarter and more knowledgeable tend to be even more good at fooling themselves with ever more intricate logical constructions that serve only to justify prejudices and prior errors in thinking and behavior.
In fact, if we heed not the soundness or cogency of our own arguments, their validity or strength, and the truth of the premises we reason from, then merely being informed of logical errors, where this is applied only to the arguments of others, will do us not good.
This is why I have difficulty taking religious apologists seriously, since few seem very concerned at all for the logic or assumptions going into their arguments, yet are all too eager to accuse their opponents of fallacies, even where such errors have not actually been made. Some fallacies exist only in the mind of the beholder.
This is something to be careful of when evaluating arguments.
Brilliance and learning offer no guarantee against gullibility and errors in reasoning.
Often, our tendency to dismiss and rationalize criticism in defense of our notions and presumptions, when we are not honest with ourselves, must be checked by a concern for more than just subjective truisms and opinions — we need criticism, when its valid, as a counterbalance for our own mistakes and sloppy thinking.
No one who really understands logic—what it is, what it’s good for, what it can’t do—actually believes that simply knowing about logical fallacies actually make anyone perfectly logical and rational; there is no such person alive, save those with some rare brain pathologies or neurological damage. Such unfortunates, being totally rational, lack the necessary drives to action provided by emotions.
When we think our way from A to B to C, and so on, from a set of facts, observations or assumptions we treat as facts, to a conclusion on some matter of importance to us, whether certain or tentative, we are engaged in reasoning.
To do so well requires skill, effort and due care in our thinking—most of us are poorly equipped at first with the mental software to to it reliably and effectively, but we can learn.
Though we are reasoning animals, we are often not as reasonable as we could be, with the fallacies, biases, and shortcuts in our thinking that we commit sometimes with disturbing regularity, and which make it necessary for us to continually scrutinize our thinking and motivations—metacognition; thinking about our thinking.
So reason alone can say nothing about truth, only validity, for reason is truth-preserving, not truth-finding. Reason is useful for assessing the consistency and validity of statements, though by itself, bereft of observation, assumptions or facts it may even be sterile and needs by itself no referent to the real world. Formal structures of reasoning are not literally how we think—they are a reconstruction of our thinking that makes intuitive sense, a convenient model of thought that serves the purpose of focusing and clarifying our understanding.
Informal reasoning is hounded by the problem of induction, the fact that all inductive reasoning is based on the assumption of the regularity of nature, which cannot be proven deductively and only with circularity by induction itself. But this is not really a problem once you consider that inductive reasoning is concerned, not with proof, but with probability. We can bite the proverbial bullet and trudge on, without needing certainty in the justification of our reasoning.
Proof, absolute, physical and concrete especially, is a will-o-the-wisp outside of mathematics and formal logic, and it is induction, not deduction, that is concerned by contingent matters of reality where we need confidence, not certitude.
So we must use reason, use it well and use it often, but remember the purpose it serves. It has been called by Professor Marianne Talbot “the ultimate transferable skill”—it may be used for almost anything—but keep it in its place as a useful tool, only one of which we use to aid our thinking, and while a worthy piece of equipment, to bear in mind it is not a final goal, only a way of reaching them.
“Logic is the beginning of wisdom, not the end.” ~ Leonard Nimoy as Mr. Spock, from Star Trek