The Difficult Problem of Truth
The Difficult Problem of Truth
THE DIFFICULT PROBLEM OF TRUTH
Now then, let's take the really difficult case. That difficult case is the case in which you ask, How do I test the correspondence between my own mind and reality, the world, to find out whether what I think is true? Let me show you why this is such a difficult case. Here we have the mind and here we have reality; and the mind is trying to know reality. In the mind is thought. Reality consists of existences. And those existences are things to be apprehended or known. But the thought, "Is that reality in my mind?" that thought is the reality that is apprehended. I don't have in my mind two things, my thought and the object of my thought. Whatever is in my mind is in my mind, and I can't know any "grasp of reality." I have no way of getting hold of reality except by knowing it. But then I can't test whether I know it or not by comparing what I know with what I am trying to know. Don't you see that in this case you can't make the comparison? There is no way of making a direct test between the two things that are supposed to correspond.
Let me put it to you another way. I express my thoughts in statements or propositions. Reality consists of the facts about which I am trying to make the propositions. And the propositions are true if they correspond with the facts. And the facts are the things to be known. The facts not as known, but to be known. The propositions are the facts as I think I know them. It isn't as if I had in one hand the propositions and in the other hand the factsa nd could look at them and say, "Oh, I see. My propositions correspond to the facts," because I have no grasp of the facts except in my own propositions about them. Hence I have no way of making a direct comparison between my propositions and the facts they are trying to state. So there is no direct or even indirect way of telling whether what I think, what I say, my propositions and judgments, correspond with the way things are.
And there is not even an indirect way of doing this because I can't ask "reality" questions the way I can ask another person questions and find out whether what I think agrees with what he thinks. I can't ask reality questions. Or, I can ask the questions, but I can't get any answers. Reality won't speak back to me. And so there is no way of getting by communication the direct or indirect test of whether what I think, what is in my mind, corresponds with reality and the way things are. That is the problem of truth. It's not the problem of knowing what truth is, but the problem of telling whether what I think is true is really true, if truth consists in the correspondence of my mind with reality.
CONSISTENCY IS NEEDED FOR TRUTH
There is the beginning of a solution to this problem. Staying within my own mind, let's suppose I make two statements. Let me call one of them proposition "p" and the other proposition "q". Those are two separate statements. Anything you want to say. Suppose these two statements are contradictory. (In my case it would be what I heard at church two Sundays ago---Unless you are in my church getting health, you have no hope. That's "p". "q" Would be his next statement. ---There's always hope.) Suppose they are like the statements "a is b and a is not b," or "two plus two equal four and two plus two does not equal four." Now we know, don't we, that both can't be true? In fact, one must be true and one must be false. And this test of contradiction or noncontradiction, or consistency, is the beginning of a sign within our own minds, just staying within our own minds and having nothing but the things we think ourselves, our own thoughts; we know that if we contradict ourselves or if we think contradictory things, we are missing the truth somewhere. And this is an interesting point, because for consistency or coherence or the absence of contradiction to be a sign of truth and falsity, or a difficulty about truth and falsity, it self-presupposes that there can be a correspondence between the mind and reality. For if reality were full of contradictions, then the presence of contradictions in the mind would not be a test or a sign of truth or falsity. Only if reality is non-contradictory, if there are in the world of existence no contradictions, we are committed to thinking that which we find a contradiction in our own minds, we have at least come into contact with one thing which is true and one which is false.
Most philosophers are not satisfied with this sign of truth. I say most, there are some exceptions; some philosophers think this is quite sufficient. For example, Descartes takes the view that when our own ideas are quite clear and distinct, when they are so clear and distinct that they are free from all contradiction, then we know we have the truth, then we are sure, we are certain of our possession of thet ruth. And Spinoza says, for example, "What can be clearer or more certain than a true idea as the standard of truth? Just as light reveals both itself and the darkness, so truth is the standard of itself and of the thoughts."
But this is not sufficient, I think. And I would like to show you why it is not. Suppose these two propositions are contradictory. What we know then is that one must be true and one must be false. But which? Either one could be true, either one could be false; we don't know which is true or false from knowing that their being contradictory makes one of them true and one false. How do we solve that problem? We could solve that problem only if in our mind there are some propositions or principles which are given as true, which we are certain about as true; so that these can be used as the measure or standard of thet ruth in other propositions. If, for example, we were absolutely sure that proposition "p" is true, then we would know that if "q" contradicts it, "q" is false. But we have to know first that "p" is true. And we can't know that simply from the fact that p contradicts q. To solve this problem fully we must have some assurance about certain propositions as true and use them to measure truth and falsity in others.
Aristotle makes this point, I think, very clearly when he says, "The human mind uses two kinds of principles. There are the unquestionable truths of the understanding which are axioms or self-evident truths of the understanding which are axioms or self-evident truths and there are the truths of perception, truths which we know, which we possess, when we perceive matters of fact, such as, "Here is a piece of paper in my hand," or "Here is a book, I see a book, I observe a book." That is a matter of fact I can't have any doubt about, just as the self-evident truth that the whole is greater than the part is a truth of my understanding about which I can have no doubt.
Now all that moderns have added to this is an elaborate, carefully, worked-out logic of the methods of empirical verification. But all the truth can be tested by finding whether or not anything else agrees with the facts we know by observation or agrees with the principles which are self-evident to our understanding. With these two at either extreme, we can tell whether anything else we think is true by seeing that it doesn't contradict this or this. I think if you will reflect about what I have said, you will see that it begins to solve the problem of how we tell whether a given statement is true or false in terms of the way that statement accords or disagrees with self-evident truths or truths of immediate perception of matters of fact.
THE IMMUTABILITY OF TRUTH
I think the time is almost up, but I would like to spend a moment more on that very interesting problem about the mutability of truth. Is truth eternal or does it change? There's no question that people change their minds, that the human face in the course of centuries passes from knowledge to error or from error to knowledge in the opinions that it holds. But this is a change in the human mind and not a change in the truth or in what is true. For example, the opinion that the earth was flat, if it ever was false, is always false. And the opposite opinion, that the earth in which we live is round, if it ever was true, is always true. The fact that people have changed their minds about whether the earth is flat or round doesn't make the truth of the matter itself change at all.
But you may say to me, Suppose that the earth tomorrow or next year were to change itself and suddenly become flat or oblong or something else, wouldn't the proposition that the earth is round become false? No, because if I were careful and exact enough, I would say that from the beginning until this year, the earth has been round. So that if next year the earth changed its shape, my proposition still would be true, because it would always remain true that up to this year the earth had been round. Hence I think it is fair to say that truth itself is immutable, even if we as humans in our thinking do not possess the truth immutably.
--Mortimer J. Adler "How to Think About Truth"
THE DIFFICULT PROBLEM OF TRUTH
Now then, let's take the really difficult case. That difficult case is the case in which you ask, How do I test the correspondence between my own mind and reality, the world, to find out whether what I think is true? Let me show you why this is such a difficult case. Here we have the mind and here we have reality; and the mind is trying to know reality. In the mind is thought. Reality consists of existences. And those existences are things to be apprehended or known. But the thought, "Is that reality in my mind?" that thought is the reality that is apprehended. I don't have in my mind two things, my thought and the object of my thought. Whatever is in my mind is in my mind, and I can't know any "grasp of reality." I have no way of getting hold of reality except by knowing it. But then I can't test whether I know it or not by comparing what I know with what I am trying to know. Don't you see that in this case you can't make the comparison? There is no way of making a direct test between the two things that are supposed to correspond.
Let me put it to you another way. I express my thoughts in statements or propositions. Reality consists of the facts about which I am trying to make the propositions. And the propositions are true if they correspond with the facts. And the facts are the things to be known. The facts not as known, but to be known. The propositions are the facts as I think I know them. It isn't as if I had in one hand the propositions and in the other hand the factsa nd could look at them and say, "Oh, I see. My propositions correspond to the facts," because I have no grasp of the facts except in my own propositions about them. Hence I have no way of making a direct comparison between my propositions and the facts they are trying to state. So there is no direct or even indirect way of telling whether what I think, what I say, my propositions and judgments, correspond with the way things are.
And there is not even an indirect way of doing this because I can't ask "reality" questions the way I can ask another person questions and find out whether what I think agrees with what he thinks. I can't ask reality questions. Or, I can ask the questions, but I can't get any answers. Reality won't speak back to me. And so there is no way of getting by communication the direct or indirect test of whether what I think, what is in my mind, corresponds with reality and the way things are. That is the problem of truth. It's not the problem of knowing what truth is, but the problem of telling whether what I think is true is really true, if truth consists in the correspondence of my mind with reality.
CONSISTENCY IS NEEDED FOR TRUTH
There is the beginning of a solution to this problem. Staying within my own mind, let's suppose I make two statements. Let me call one of them proposition "p" and the other proposition "q". Those are two separate statements. Anything you want to say. Suppose these two statements are contradictory. (In my case it would be what I heard at church two Sundays ago---Unless you are in my church getting health, you have no hope. That's "p". "q" Would be his next statement. ---There's always hope.) Suppose they are like the statements "a is b and a is not b," or "two plus two equal four and two plus two does not equal four." Now we know, don't we, that both can't be true? In fact, one must be true and one must be false. And this test of contradiction or noncontradiction, or consistency, is the beginning of a sign within our own minds, just staying within our own minds and having nothing but the things we think ourselves, our own thoughts; we know that if we contradict ourselves or if we think contradictory things, we are missing the truth somewhere. And this is an interesting point, because for consistency or coherence or the absence of contradiction to be a sign of truth and falsity, or a difficulty about truth and falsity, it self-presupposes that there can be a correspondence between the mind and reality. For if reality were full of contradictions, then the presence of contradictions in the mind would not be a test or a sign of truth or falsity. Only if reality is non-contradictory, if there are in the world of existence no contradictions, we are committed to thinking that which we find a contradiction in our own minds, we have at least come into contact with one thing which is true and one which is false.
Most philosophers are not satisfied with this sign of truth. I say most, there are some exceptions; some philosophers think this is quite sufficient. For example, Descartes takes the view that when our own ideas are quite clear and distinct, when they are so clear and distinct that they are free from all contradiction, then we know we have the truth, then we are sure, we are certain of our possession of thet ruth. And Spinoza says, for example, "What can be clearer or more certain than a true idea as the standard of truth? Just as light reveals both itself and the darkness, so truth is the standard of itself and of the thoughts."
But this is not sufficient, I think. And I would like to show you why it is not. Suppose these two propositions are contradictory. What we know then is that one must be true and one must be false. But which? Either one could be true, either one could be false; we don't know which is true or false from knowing that their being contradictory makes one of them true and one false. How do we solve that problem? We could solve that problem only if in our mind there are some propositions or principles which are given as true, which we are certain about as true; so that these can be used as the measure or standard of thet ruth in other propositions. If, for example, we were absolutely sure that proposition "p" is true, then we would know that if "q" contradicts it, "q" is false. But we have to know first that "p" is true. And we can't know that simply from the fact that p contradicts q. To solve this problem fully we must have some assurance about certain propositions as true and use them to measure truth and falsity in others.
Aristotle makes this point, I think, very clearly when he says, "The human mind uses two kinds of principles. There are the unquestionable truths of the understanding which are axioms or self-evident truths of the understanding which are axioms or self-evident truths and there are the truths of perception, truths which we know, which we possess, when we perceive matters of fact, such as, "Here is a piece of paper in my hand," or "Here is a book, I see a book, I observe a book." That is a matter of fact I can't have any doubt about, just as the self-evident truth that the whole is greater than the part is a truth of my understanding about which I can have no doubt.
Now all that moderns have added to this is an elaborate, carefully, worked-out logic of the methods of empirical verification. But all the truth can be tested by finding whether or not anything else agrees with the facts we know by observation or agrees with the principles which are self-evident to our understanding. With these two at either extreme, we can tell whether anything else we think is true by seeing that it doesn't contradict this or this. I think if you will reflect about what I have said, you will see that it begins to solve the problem of how we tell whether a given statement is true or false in terms of the way that statement accords or disagrees with self-evident truths or truths of immediate perception of matters of fact.
THE IMMUTABILITY OF TRUTH
I think the time is almost up, but I would like to spend a moment more on that very interesting problem about the mutability of truth. Is truth eternal or does it change? There's no question that people change their minds, that the human face in the course of centuries passes from knowledge to error or from error to knowledge in the opinions that it holds. But this is a change in the human mind and not a change in the truth or in what is true. For example, the opinion that the earth was flat, if it ever was false, is always false. And the opposite opinion, that the earth in which we live is round, if it ever was true, is always true. The fact that people have changed their minds about whether the earth is flat or round doesn't make the truth of the matter itself change at all.
But you may say to me, Suppose that the earth tomorrow or next year were to change itself and suddenly become flat or oblong or something else, wouldn't the proposition that the earth is round become false? No, because if I were careful and exact enough, I would say that from the beginning until this year, the earth has been round. So that if next year the earth changed its shape, my proposition still would be true, because it would always remain true that up to this year the earth had been round. Hence I think it is fair to say that truth itself is immutable, even if we as humans in our thinking do not possess the truth immutably.
--Mortimer J. Adler "How to Think About Truth"