Given a particular conclusion, we can, normally, trace it back to the very basic premises that constitute it. The entire process of reaching such a conclusion(or stripping it to its basic constituents) is based on logic(reason). So, however primitive a premise may be, we don't seem to reach the "root" of a conclusion. Do you believe that goes on to show that we are not to ever acquire "pure knowledge"? That is, do you think there is a way around perceiving truths through a, so to say, prism of reasoning, in which case, nothing is to be trusted?

There's a lot going on here. You begin this way:

Given a particular conclusion, we can, normally, trace it back to the very basic premises that constitute it.

If by "conclusion" you mean a statement that we accept on the basis of explicit reasoning, then we can trace it back to the premises we reasoned from simply because we've supposed that there are such premises. On the other hand, most of what we believe doesn't come from explicit reasoning. (I don't reason to the conclusion that I had a burrito for lunch. I just remember what I ate.) And even when it does, the premises don't usually constitute the conclusion. The easiest way to see this is to consider non-deductive reasoning. A detective may conclude that Lefty was the culprit because a number of clues point in that direction. Maybe a witness saw someone who looks like him; maybe he had a particular motive for the crime. But the clues don't constitute Lefty being the criminal; they merely make it likely. After all, even given all the clues the detective has, it might turn out that Lefty is innocent&emdash;even though the guilty person looked like him, and even though Lefty had a motive, etc. etc. etc.

But even if we set the word "constitute" aside, and even if we agreed (though we shouldn't) that normally we can trace a belief back to a set of basic premises it follows from, it would be a mistake to conclude either that we can always do this or that we always should be able to. If the premises are basic enough, they may not need to be defended. For example: suppose I conclude that Alice and Carol are the same height because I have reason to believe that Alice and Bob are, and, independently, that Bob and Carol are. If I add the premises that two heights equal to a third height are equal to one another, I get my conclusion (though outside of logic class, we wouldn't bother to state such an obvious truth.) But that premise seems to me to be rock-bottom and rightly so; it doesn't need defending and in particular, it doesn't need to be derived from other premises.

You ask "do you think there is a way around perceiving truths through a, so to say, prism of reasoning, in which case, nothing is to be trusted?" If by "perceiving truths through a... prism of reasoning" you mean deriving them from other premises, then the fact (noted above) is that this isn't the way we do operate, nor is it the way we should operate. My lunch example is pretty typical. We don't reason to most of our beliefs, and there isn't the slightest (heh!) reason to think we should. We see things, we hear things, we remember things, we're told things. And we come to believe accordingly. Usually that's just fine. A certain sort of philosophical skeptic might think otherwise, though there are few real-life examples of such skeptics and even fewer reasons to think we're obliged to refute them. In specific cases, there can be good reasons to worry about whether we're justified in holding particular beliefs, but those are cases whether the evidence is conflicting or weak or ambiguous or complicated or... The mere fact that we don't have an argument for every brick in the edifice of belief isn't a good reason. Or to put it another way, if someone thinks it is a good reason, they need to give the rest of us a reason to think so.

A coda of sorts: when people first start to think philosophically about knowledge, they may find themselves captive to Descartes-style demons. A more promising way to think about knowledge is to set aside the worry that we don't really have any and look to our best examples of what pretty clearly seems to be knowledge. Ordinary perceptual knowledge is one kind of case; so is scientific knowledge. There's a lot to be learned by adopting that approach, but it will be clear early on that one of the lessons will not be that knowledge typically has a deductive structure, let alone rules that demand infinite deductive descent.

It's not clear to me what you're asking, but I'll do my best.

Given a particular conclusion, we can, normally, trace it back to the very basic premises that constitute it.

I doubt we can do that without seeing the conclusion in the context of the actual premises used to derive it. The conclusion Socrates is mortal follows from the premises All men are mortal and Socrates is a man, but it also follows from the premises All primates are mortal and Socrates is a primate. So which pair of premises are "the very basic premises" for that conclusion? Outside of the actual argument context, the question has no answer.

I don't know what you mean by "the root of a conclusion," but you seem to be suggesting that any knowledge is impure if it depends on -- or if it was acquired using -- any reasoning at all. Perhaps the term inferential would be a better label for such knowledge. On this view, even if I have direct knowledge that I am in pain (when I am), I have only inferential knowledge that Some Anglophone is in pain if I derive the latter proposition from the former by way of the premise I am an Anglophone.

Your final sentence suggests that reason is like a prism that distorts any image seen through it. I don't see reason as a distorting influence on knowledge but, instead, as an essential tool for acquiring all of the inferential knowledge that we have. It's true that bad reasoning can take you from premises you know to a conclusion that you fail to know, but bad reasoning is the fault of the reasoner, not the fault of reason.

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