Truth, Opinion, and Knowledge
I've started reading through Mortimer J Adler's How to Think About the Great Ideas: From the Great Books of Western Civilization (edited by Mr Max Weismann), and I am struck by his insights into ideas which ought to be almost common-sense, and yet which are largely overlooked, ignored, or forgotten today. The book itself is not necessarily meant to be read in any broad order*--there are some chapters which are clearly sequels to each other--but Mr Weismann did a good job in arranging it so that the first topic addressed is Truth and the Second is Opinion.
In particular, it's worth noting that Dr Adler does not oppose Truth to Opinion. Rather, he opposes Truth to lies (at least implicitly) and Opinion to Knowledge. In other words, just because something is an opinion does not mean that it isn't also true. The "fact of opinion" dichotomy which many of us learned in elementary school is a false dichotomy, whatever may be its supposedly scientific merits.
Here's what Dr Adler has to say about Truth:
There are two distinct questions here [regarding truth] which are often confused. One is the question, "What is truth?" a question that calls for the definition of truth. And the other question is a question--listen to the difference--not "What is truth?" but "What is true in a particular case?" or "What is true?"...The easy question or at least the easier of the two is the question "What is truth?"....We speak truthfully when our speech corresponds or conforms to what we think. And there is truth in communication between persons when, in using words, their two minds correspond with one another. The ideas in one person's mind correspond to the ideas in the other. What remains then, what is the third and difficult case? It is the case in which there is a correspondence between the mind itself and reality, the world in which we live. And when there is this kind of correspondence between the mind and reality, the the mind has truth in it about the world it is trying to know or understand....[The really] difficult case [of truth] 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. 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.
To summarize, truth is the "correspondence between the mind and reality," but there is an additional epistemological problem of knowing that our minds really do correspond to reality. This is a reasonably good definition for truth (and for what is true), but it has its flaws. First, it would be more accurate to say that our mind contains truth to the extent that our thoughts and ideas correspond to reality, whereas Adler seems to have defined the correspondence itself between mind and reality as truth. We who recall our Lord's words that He is Truth (John 14:6) know that Adler's definition falls somewhat short of this. After all, Christ is not a correspondence, though we can have true conceptions of Him in our mind. The implication therefore is that Truth exists not inside of our minds, but outside of (and independent from) them. Even disregarding the explicitly Christian example of Christ as Truth, we might note that our own existence is true, and not merely a figment of our own minds which--if our existence were such a daydream--would not themselves exist to hold figments or daydreams.
Second, a person's mind might contain knowledge of the truth which he has nevertheless rejected. Adler assumes that knowledge of the truth is all that is needed, forgetting that man has a will and can choose to reject or resist a known truth: a fact of which Adler himself eventually became somewhat aware. To be fair, this distinction can be read into Dr Adler's definitions for truth (especially since he explains that another definition for truth means that a person's words correspond to his thoughts), but it is not so explicitly stated as it ought to be. A man can always fool himself into believing that what he sees and hears, touches, tastes and smells--in a word, what he experiences--is illusory. His mind would thus have knowledge of the truth, and would even correspond to the truth, save for this one rejection, of his senses as a reliable witness to reality. On the other hand, to say that a man's mind must fully correspond and conform to reality is to do injustice to his limited ability to know truth. He need not grasp all of reality to correctly grasp some of it. A more precise usage might be to say that a man possessing truth to the extent that his mind conforms or corresponds to reality and that he moreover acknowledges and consents to that conformity**. Note that he need not actually prove that his mind conforms to reality--that is, after all, a part of the "harder" case.
On the whole, however, his definitions and distinctions here work. He was, after all, working outside of a Christian framework at the time, and was also trying to reach a very broad audience in a limit time frame. All-in-all, there is the problem of possessing truth in that the mind recognizes and conforms itself to reality; and there is the problem of have certainty that the mind really has conformed itself to reality, that the thoughts and ideas in the mind really do correspond to reality, at least as far as they go.
Now, the opposite of a truth is either a lie or a falsehood. The former involves a deliberate disparity between a person's thoughts and his words; the latter involves a difference between his thoughts and that part of reality to which they are meant to correspond. This can be contrasted with the ideas of Opinion and Knowledge. First, here's what Professor Adler has to say about Opinion and Knowledge:
"Knowledge consists in having the truth and knowing that you have it, because you know why what you think is true is true. Whereas opinion consists in not being sure that you have the truth, not being sure whether what you say is true or false. And even if what you say happens to be true, you are sure because you don't know why it's true...Opinion can be right or wrong. We all recognize this, I think. But think a moment, knowledge can't be false, knowledge can't be wrong."
Note that knowledge involves being able to answer both the "easy" and the "hard" problems of truth. That is to say, knowledge involves the mind's possessing some truth and having certainty that it possesses a truth and not a mere possibility. The thoughts in the mind are correct, and the mind is absolutely certain that they are correct. Note also that opinion can be true, or it can be false. The difference Adler gives between knowledge and opinion is that knowledge must always be true--whereas opinion may or may not be--and that with knowledge there is a certainty that the thought in question really does correspond to reality.
Here is another problem. Can an opinion ever be knowledge? Adler himself poses a similar question, though in a different form, by asking if one man may possess as knowledge what another holds as mere opinion; he does not, however, attempt to answer this question in any detail. I am posing a slightly different question: is it necessary that a man must be able to "prove" that his thoughts correspond to reality in order for it to be said that he has knowledge, or does he merely need to have some certainty--however poorly founded--that his thoughts really do correspond to reality?
The great advantage of an affirmative to this latter questions is that it avails us of being able to make use of the expertise of others. It requires that we place some trust in them, that we trust that they are trying convey their knowledge to us accurately and honestly, and that we understand them when they do so (that is, that the second condition for truth given by Adler is met). This advantage is countered by the pitfall that a person who does not base his "opinion" on a certainty of personal, first-hand evidence (or proofs) is much more difficult to correct when he is in error. In other words, he might soon mistake his incorrect opinions for knowledge, and any number of falsehoods for truths. This is ultimately the error of the fundamentalist--Protestant, Atheist, Muhammedan, and even Catholic. When his opinion is incorrect, there is no means for it to be corrected, not by authority nor by reason.
On the other hand, if we require--as Adler does--that man must always be able to prove with evidence that he has knowledge and not a mere opinion *3*, then we encounter the problem of rationalism, of modernism. It insists that nothing can be known until proven, that there can be no revelation and no authority outside of your own mind. To his credit, Adler notes that religious faith is in an altogether different category from knowledge-or-opinion; however, this problem is not limited only to religious faith. A child learning to count cannot prove that one is followed by two—but this does not mean that this proposition is a mere opinion even in the case of the child who holds it. There are, in fact, any number of concepts or thoughts which few if any people can really prove which nonetheless count as actual knowledge: because the bar for proving something is, in our age our rationalist pretensions, quite high.
Father Stanley L Jaki summarizes this dilemma quite aptly (if unintentionally) in his Miracles and Physics when he writes:
Courts of all all levels, governments of all jurisdiction, depend on witnesses and their plain witnessing and so do laboratories. In none of these forums can a discrimination against plain witnessing of unusual facts be condoned or else the most important cases may be prejudged and the only avenues of progress blocked. Had Oersted refused to believe his eyes when they noted that a magnetic needle which he placed under a live wire turned in a direction which he believed to be impossible, the discoveries of Faraday and Maxwell might not have followed as they did. The discovery of the world of atoms depended on Roentgen's chance witnessing the formation, that was not expected to happen, of the negative image of a key on a photographic plate. Far more importantly, would Newtonian science have developed at all if Kepler had not unconditionally trusted Tycho Brahe's eyes in making countless naked-eye observations about the positions of the planet Mars?
Perhaps the solution to this dilemma to recognize that knowledge need not always prove itself to be knowledge. Indeed, our knowledge is much greater for not always having to be proven--as the skeptic demands--but rather for being accepted when passed on by reliable sources. Tradition, custom, and prescription are among of the greatest sources of knowledge--and more importantly of wisdom--which are known to man; these things may, of course, be questioned, and to some extent every man does test these tings at some point during his life. He cannot, however, find any lasting peace if he demands of them incontrovertible proofs for every fine detail before he will accept the whole of it. As Chesterton put is, "You can only find truth with logic if you have already found truth without it."
Even aside tradition, custom, and prescription, there are plenty of cases in which a person might have knowledge without having to rigorously test that knowledge. We need not duplicate every scientific experiment to accept the validity of the theories of modern physics: and though these theories are not necessarily complete, and can be changed, they still do represent genuine knowledge. It is not be mere opinion that we are able to construct a laser, even if we don't understand, the finer details of quantum mechanics which underlie lasing. Moreover, if my best friends tells me that his wife is pregnant, I need not see her swelling belling--let alone waiting for the baby to be born--to know that she is in fact pregnant. That I can't verify my friend's statement does not mean that it is for me a mere opinion that his wife is pregnant; rather, it is knowledge, a fact held with certainty *4*.
This is, of course, not to deny that we should seek certainty. We should be "ready always to satisfy every one that asketh you a reason of that hope which is in you" (1 Peter 3:15). We should try to verify our opinions (and beliefs) as best we can; but the simple fact is that we cannot do this for every bit of knowledge which passed on to us, nor is it especially productive for us to try. Far better is it to verify what we can, and trust in the credibility and reliability of the "witnesses" who testify to whatever knowledge they pass on to us, to trust that they or someone else along the line has verified the information which we are receiving. Some of us may be called to verify any given bit of information: but all of us can't verify everything all of the time. It doesn't mean that there can't be a measure of certainty attached to this information, that is, if our thoughts concerning this part of reality are true, and we have certainty based on a credible witness, then these thoughts are not merely opinion, but knowledge. Spending time to verify this knowledge is only useful if it grants us either peace of mind or a greater understanding. Otherwise, our knowledge is meant to be acted or built upon.
*The chapters are actually manuscripts from a series of half-hour television broadcasts featuring Adler. The original ordering of the episodes/ideas addressed has been largely lost, though for some ideas he spends more than one episodes, and the order among these is often fairly clear.
**Thus, a person who resists a known truth is therefore lacking possession of the truth to the extent that he knows the truth of a situation or question but rejects that truth, either by accident or by sheer act of will. As an example, I can tell you some truth which you have never before heard. For example, I might tell you, even show you, that murder is a grave sin. This is a truth, a fact. You may hear all of the arguments, and so in a sense come to "understand" that murder is intrinsically evil; but you may then choose to reject this truth, that is, you can "decide" that all of my reasons are little more than opinions, and thus that murder is not intrinsically wrong. The result is that you possesses truth but rejected it. A part of your mind really does conform to reality--to the extent that you understand the arguments and evidence presented to you; but this part of your mind is nullified by the part which decides that these arguments and evidences are themselves not true, and hence that the conclusion "murder is intrinsically evil" is not true, either.
*3* Adler actually goes on to hold something like this in the next chapter of the book. He says outright that most of what children learn in schools is "right opinion." He also suggests that when a student learns "right opinion" and then can do little more than make an argument from authority, the student is not so much learning as being indoctrinated. It would be interesting to find our how, exactly, he would classify the case in which a person really does learn something--that is, gain knowledge which he can prove or give good evidence for and have certainty about--but then later forgets the proof yet retains the conclusion. Is such a person who says I've seen the proof for the Pythagorean Theorem, but I forget how it goes" therefore arguing based on the authority of his past self?
*4*I suppose that it is possible to quibble here over certainty by saying that I have to establish my friend's credibility in this case. But if my friend is only joking, it does not therefore mean that it is my opinion that his wife is joking. There is room to argue that certainty in this case is established based on credibility.