Well, what I mean by that is, when we are forced to evaluate opposing truth claims, what is the final authority? Is it force of some kind or another? There are many examples of this. They range from parental authority to peer pressure to physical intimidation to lethal violence. Believe this or I'll kill you. Believe this or we won't accept you into the group. Believe this or you can't have the car keys. Or is it something else that really tells us what is true? I trust that you see that however compelling these "arguments" may be from a social point of view, they are completely irrelevant in determining what is true. No, for that, we need reason. Reason is the ultimate authority for what is true in and of the universe.
That's a bold claim, perhaps, but I think I can back it up pretty easily with a simple example. Let's say that you deny my claim that reason is the ultimate arbiter of truth claims in this or any universe that could possibly exist. Fair enough. Now what I will ask you to do is to justify your claim. Why is it that reason is NOT the ultimate arbiter of truth?
Now if you want to be taken seriously, this is when you have to make an argument for your assertion. But the problem is (for you), that as soon as you begin to give me reasons why reason doesn't rule, you are, guess what, reasoning. Yes, reason is another one of those "first principle" kind of things. It is inescapable. It is part of our nature. It is part of the fabric of the universe. It is a universally effective method for arriving at truth. It is universally effective today. It was universally effective yesterday. It was universally effective 14.7 billion years ago and will still be universally effective 300 billion years from now. It is just as effective on the moon, or on some distant star in a galaxy far, far, away. So, we see that reason is pretty powerful. In fact, I will again say that even God, if He exists, cannot defy reason. One of the things we will consider later on is why this might be so. Why is it that reason, or we might say "the law of thinking," is universally valid at all times and everywhere?
So the bottom line is that to deny reason is to use reason. Therefore, it is self-contradictory to deny that reason is the ultimate arbiter of truth. And since we cannot deny it, we must accept it. Well, we must accept it if we want to retain any sort of intellectual credibility or integrity. After all, how can one be expected to be taken seriously if one denies what is obvious to everyone? Or if one denies what literally cannot be rationally denied? I belabor this point only for the reason that eventually I will point out example after example of "intellectuals" who, on the one hand, claim that they are disciples of reason. They claim the intellectual high ground because of their unshakeable commitment to reason. Yet, as we will see, they could not possibly be more irrational. For time and time again, they will deny the very things that they profess when it suits them. They will violate the law of non-contradiction. They will violate the laws of being and identity. They will deny the rules for making valid inferences. They will commit all kinds of logical fallacies. It's really an interesting thing to see this. And they get away with it, by and large. But not here.