Some of these statements are true or false according to the rules we have stipulated: the sum of the angles of a triangle is 180 degrees only in the context of a Euclidean system of postulates; that water boils at a hundred degrees at standard atmospheric pressure, that is, at sea level, is true not only if we accept a law of physics elaborated through inductive generalization, but also on the basis of the definition of degrees centigrade; an apple is an angiosperm only on the basis of certain rules of botanical classification.
Some require us to trust facts ascertained by others before us: we believe it is true that Napoleon died on May 5, 1821, because we accept what the history books tell us, but we must always recognize the possibility that an unpublished document discovered tomorrow in the British naval archives might show that he died on another date. Sometimes for utilitarian reasons we adopt an idea as true that we know to be false: for example, to find our way in the desert, we behave as if it were true that the sun moves from east to west.
As for statements of a religious nature, we shall not say they are undecidable. If the evidence of the Gospels is accepted as historical, the proof of the divinity of Christ would be accepted as such by a Protestant. But this would not be so for the teachings of the Catholic Church. The statement regarding embryos having a soul depends entirely on stipulating the meanings of expressions such as life, human, and soul. Thomas Aquinas, for example (see the essay “No Embryos in Paradise”), claimed that, like animals, they had only a sensitive soul and therefore were not yet human beings equipped with a rational soul, and would not participate in the resurrection of the flesh. Today he would be accused of heresy, but at that very civilized time they made him a saint.
It is therefore a matter of deciding each time which criteria for truth we are using.
It is on the very recognition of various degrees of verifiability or acceptability of a truth that our sense of tolerance is based. I may be obliged, from a scientific and educational point of view, to fail a student who claims that water boils at ninety degrees, like the right angle—as was apparently once suggested in an exam—but even a Christian ought to accept that for some people there is no other god than Allah and Muhammad is his prophet (as we likewise ask Muslims to do for Christians concerning Christian doctrine).
And yet, in light of recent controversies, it seems that this distinction between different criteria of truth, typical of modern thought and in particular of logical scientific thought, produces a relativism that is seen as a historical malaise of contemporary culture, which rejects all idea of truth. But what do anti-relativists mean by relativism?
Some encyclopedias of philosophy tell us there is a cognitive relativism, by which objects can be known only under conditions determined by human faculties. But in this sense Kant would also have been a relativist, and he certainly didn’t reject the possibility of setting out laws of universal value—and what is more, he believed in God, if only on moral grounds.
Yet in another philosophical encyclopedia we find that relativism means “every idea that does not admit absolute principles in the field of knowledge and action.” But it is a different matter to reject absolute principles in the sphere of knowledge or the sphere of action. There are people who are prepared to assert that the statement “Pedophilia is evil” is a truth relative only to a particular system of values, seeing that it was or is accepted or tolerated in certain cultures, but who are nevertheless prepared to assert that the Pythagorean theorem must be valid for all times and all cultures.
No one could seriously include Einstein’s theory of relativity under the label of relativism. To say that a measurement depends on the conditions of movement of the observer is regarded as a valid principle for every human being in every time and place.
Relativism, as a philosophical doctrine as such, came into existence with nineteenth-century positivism, together with the claim that the Absolute is unknowable and, at most, is a movable limit of ongoing scientific research. But no positivist has ever claimed it is not possible to arrive at scientific truths that are objectively verifiable and valid for all.
A philosophical position that, on a cursory reading of the textbooks, might be defined as relativistic is so-called holism, according to which every statement is true or false (and acquires a meaning) only within an organic system of assumptions, a given conceptual scheme, or, as others have said, within a given scientific paradigm. A holist claims (rightly) that the notion of space has a different meaning in the Aristotelian system than it does in the Newtonian system, so that the two systems are incommensurable, and that one scientific system is as valid as the other to the extent to which it succeeds in explaining a series of phenomena.
But the holists are the first to tell us there are systems that cannot actually explain a series of phenomena, and that some are far better because they succeed better than the others in doing so. Thus even the holist, in his apparent tolerance, has to deal with matters that require explanation and, even when he doesn’t say so, follows what I would call a minimal realism: the belief that things exist or behave in a certain way. Perhaps we will never understand it, but if we don’t believe it exists, our research would make no sense, and it would make no sense to go on trying out new systems to explain the world.
The holist is usually said to be a pragmatist, but here again it is better not to be over-hasty in reading the textbooks: the true pragmatist, such as Peirce, did not say that ideas are true only if they prove to be effective, but that they show their effectiveness when they are true. When he supported fallibilism, namely, the possibility that all of our ideas could always be revoked in case of doubt, at the same time he stated that through the continual correction of its knowledge the human community carries forward “the torch of truth.”
What gives rise to a suspicion of relativism in these theories is the fact that the various systems are incommensurable. Certainly the Ptolemaic system is incommensurable with the Copernican system, and only in the first do the notions of epicycle and deferent assume a precise meaning. But the fact that the two systems are incommensurable does not mean they are not comparable, and it is precisely by comparing them that we understand what are the celestial phenomena that Ptolemy explained with the notions of epicycle and deferent, and we understand that they were the same phenomena that the Copernicans wanted to explain according to a different conceptual scheme.
The holism of philosophers is similar to linguistic holism, wherein a given language, through its semantic and syntactic structure, is said to impose a particular vision of the world in which the speaker is, so to speak, a prisoner. Benjamin Lee Whorf, for example, pointed out that there is a tendency in Western languages to consider many events as objects, and an expression such as “three days” is grammatically equivalent to “three apples”; whereas some Native American languages focus on the process—they see events whereas we see things. For this reason, the Hopi language would be better equipped than English for defining certain phenomena studied by modern physics.
And Whorf also pointed out that the Eskimos have four different words for snow, depending on its texture, and they would therefore see different things where we see only one. Leaving aside the fact that this suggestion has been disputed, a Western skier knows nevertheless how to distinguish between various textures of snow, and it would be quite enough for an Eskimo to meet us to understand perfectly well that when we say “snow” for the four things that he supposedly describes in different ways, we are behaving in the same way as a Frenchman who uses the word glace for ice, glacier, ice cream, mirror, and window glass—and the Frenchman isn’t such a prisoner of his own language that he shaves in the morning looking at himself in an ice cream.
Finally, apart from the fact that not all contemporary thought accepts the holistic approach, holism follows the line of those perspective-based theories of knowledge according to which reality can be given different perspectives and each perspective matches one aspect of it, even if it doesn’t exhaust its unfathomable richness. There is nothing relativistic in claiming that reality is always defined from a particular point of view (which does not mean subjective and individual), nor does the assertion that we see it always and only under a certain description stop us from believing and hoping that what we picture is always the same thing.
Alongside cognitive relativism, the encyclopedias refer to cultural relativism. First Montaigne, then Locke, had begun to understand, at a time when Europe was coming into more significant contact with other peoples, that different cultures not only have different languages or mythologies but also different conceptions of morality (all reasonable in their own context). It seems indisputable that certain
