What’s the Difference Between Fact and Opinion?
A reader wrote me to ask:
"Please could you elucidate the distinction between a fact and an opinion? I am a secondary school English teacher and there is a lot of rubbish written on this part of the curriculum that would lead to such absurdities as, for example, the atomic weight of sodium is a fact, but the proposition 'raping babies is wrong' is merely an opinion."
The manner in which “fact” is commonly pitted against “opinion” seems to rest on multiple confusions. In particular, it seems to rest, in part and in several ways, on a failure to take note of the distinction between metaphysical questions and epistemological questions. It also seems to rest in part on a rather crude and dogmatic application of the so-called “fact/value distinction”—a distinction that is, where ethics is concerned, dubious in any event. Finally, it often seems to rest as well on a failure to distinguish science from scientism.
Let’s walk through this. When people say that such-and-such a claim about sodium (for example) is a “fact,” it seems pretty clear that part of what they mean is that it is objectively true that sodium is that way. That is to say, that sodium has such-and-such chemical properties is a state of affairs that holds completely independently from human convention or subjective tastes. It seems that another part of what they mean, though, is that this objective truth about sodium has been discovered by means of unimpeachable evidence, airtight scientific arguments, and so forth. These two claims are of logically distinct types. The first is a claim about the way the world is—all it a metaphysical claim—while the second is a claim about how we know about the way the world is—call it an epistemological claim. And this difference entails a corresponding difference between two different senses of the word “fact”:
Fact (1): an objective state of affairs
Fact (2): a state of affairs known via conclusive arguments, airtight evidence, etc.
In the same way, when people say that such-and-such is “a matter of opinion,” it seems clear that what they mean, in part, is that it concerns something that is not known via conclusive arguments based on airtight evidence, etc. but is at best believed in on the basis of controversial arguments. But it seems that they also at least sometimes mean that it not a claim that could be objectively true in any event—that its truth could only ever be a matter of convention or subjective taste. Here too we have claims of two logically different types, where the first is an epistemological claim and the second a metaphysical one. And as with “fact,” we need therefore to distinguish between two senses of the expression “matter of opinion”:
Matter of opinion (1): a state of affairs determined entirely by human convention or taste, about which no objective claims can be made
Matter of opinion (2): a state of affairs not known via conclusive arguments, unimpeachable evidence, etc., but at best believed in on the basis of controversial arguments
Now part of the problem with most “fact versus opinion” talk is that the people who engage in it do not make these distinctions. One result of this is that they fallaciously assume that if something is a matter of controversy, then there must be no objective fact of the matter about it—that is to say, that if it is a Matter of opinion (2) then it must therefore be a Matter of opinion (1) and therefore must not be a Fact (1). That this is muddleheaded should be obvious from the following example:
"The existence of Pluto is a “fact” in both of the senses we have distinguished. But though it was always a Fact (1), it was not always a Fact (2), for Pluto’s existence was of course not known for most of human history. More to the present point, during the period in which there was debate over what the relevant observations really showed, the existence of Pluto, though still (as it turns out) a Fact (1), was not a Fact (2) but only a Matter of opinion (2)."
In general, it is perfectly possible for something to be a “fact” in the first sense but not in the second sense, and therefore perfectly possible for it to be a “fact” in the first sense and at the same time a “matter of opinion,” in the second sense of that expression. It is also, for that matter, possible for something to be a Matter of opinion (1) but a Fact (2). For example, that the speed limit on most highways in California is 65 MPH is a matter of human convention, and that my favorite Scotch is Laphroaig is a matter of taste. But someone could easily acquire airtight evidence that these things are so.
So, that is one problem with most talk about fact versus opinion—it fails to make these crucial distinctions between metaphysical vs. epistemological senses of the relevant terms. But there are other problems too. Precisely because people fallaciously infer from something’s being a matter of controversy to the conclusion that there must be no objective truth about it, they tend to fall for a rather crude version of the “fact/value distinction.” They conclude that, since people disagree about morality, morality must be entirely subjective, so that even judgments like “Raping babies is wrong” must be true only as a matter of taste or convention. We all agree about “facts” but don’t all agree about morality, therefore (so the "reasoning” goes) morality must be a matter of mere “opinion” rather than “fact.” Once we make the distinctions noted above, the fallaciousness of this “reasoning” becomes obvious. And as I show in my essay on classical natural law theory and property rights, there is ample reason to reject the fact/value distinction in any case.
Finally, as the example my reader gives suggests, there also seems to be a tendency to think that what is “factual” is what can be established by means of empirical science, so that what cannot be established in that way must be merely a “matter of opinion.” The scientism implicit in this tendency is difficult to justify even when endorsed by professional philosophers. In the thinking of the average non-professional who casually pits scientific “fact” against non-scientific “opinion,” it is nothing more than a prejudice picked up from the surrounding culture. Certainly it embodies no actual rational basis for rejecting the possibility that solid philosophical arguments can rationally justify moral, aesthetic, and theological claims—thus showing such claims to be entirely “factual” in both senses of the term even if one agrees that they are not the sorts of claims which could be established on empirical scientific grounds.
In summary, then, there seem to be four errors underlying the common tendency to pit fact against opinion, to identify the former with science, and to relegate moral judgments and the like to the latter category. First, it fails to distinguish the relevant two senses of “fact.” Second, it fails to distinguish the two relevant senses of “opinion.” Third, it unjustifiably assimilates moral and other value judgments to “matters of opinion” in the first sense we distinguished. And fourth, it unjustifiably assimilates “facts” in both senses of the term to scientific facts. When we clear up all these errors, we can see that a great deal of what is said in the name of fact versus opinion is, as my reader puts it, “rubbish.”
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