A fallacy related to the one we looked at last week (the Ad Hominem fallacy) is the genetic fallacy. One commits the genetic fallacy if one argues that a proposition is false on the basis of where the idea originated from. Like the ad hominem, this fallacy invokes a kind of psychological transference where one transfers one’s disapproval of the source of an idea to the content of the idea itself. This kind of transference is fallacious because the content of an idea, its truth or falsity, depends on whether what it affirms about the world is the case and not on where the idea originated.
Examples
Consider, the ancient Greek thinker Pythagoras. Pythagoras was a religious mystic who worshipped numbers and geometrical systems as part of a broader religious scheme which included a strict diet and belief in reincarnation. Few people are aware of this; today he is best known for being traditionally credited with discovering the famous mathematical formula known as Pythagorean Theorem which affirms that, “for any right triangle, the square of the hypotenuse is equal to the sum of the squares of the other two sides”.
Now suppose someone were to reject Pythagorean theorem on the grounds that it was discovered by a odd religious mystic. This rejection would obviously be invalid. Even if tradition were correct in identifying Pythagoras with the discovery of this theorem, this does not mean that the theorem is false; its truth is determined by what the realities of math and geometery actually are, not by who discovered them.
A second example illustrates the same point. Some early defences of heliocentricism, the view that the planets in the solar system orbit the sun, originated in certain systems of sun mysticism. People worshipped the sun as a symbol of God and hence thought it fitting that the sun be at the centre. This fact about the origins of some beliefs about heliocentricism does nothing to show that heliocentricism is false. Its truth or falsity depends on location of different planets, not on how the idea was first formulated.
These examples may seem fairly obvious but they often beguile people. In Theology, for example, some theologians dismiss certain ideas as false because they originated in Greek Platonism. Yet this fact does not show these ideas are false; to show they are false one needs to show that these claims contradict known facts about the world.
Consider a common line of argument against the existence of God. People argue that the idea of God originated in wish-fulfilment or in Priests wanting to gain power over the populace or in primitive pre-scientific explanations of earth-quakes and so on. Often the evidence for such claims is scant but even if they were true these facts about the origin of the idea of God do not provide an argument that belief in God is false any more than the mystical origins of Pythagoras’ theorem shows that Pythagorean theorem is false. Again, it is factors other than the origin of the idea that matter here.
The Genetic Fallacy and other Valid Lines of Argument
As with the ad hominem fallacy, it is important to recognise that not every reference to an origin of an idea is necessarily a version of the genetic fallacy. Suppose a person has a visual hallucination of a tree in front of them. The hallucination is vivid and is convincing. The person is told that he is undergoing a hallucination and as such, his visual experience of a tree is not reliable.
Is this a version of the genetic fallacy? It might seem so as the belief was challenged on the basis of its origins – a hallucination. However, this kind of example differs from the genetic fallacy in a couple of important ways.
First, in this case the only grounds that the person has for thinking there is a tree in front of him is that he has the visual experience of seeing it. Second, in this case the objector does not argue that the belief is false, she simply argues that the grounds on which the belief is based are unreliable. This is compatible with the belief being true; it just means he does not have reliable grounds for thinking it is true.
This differs from the case of Pythagoras above. With Pythagorean theorem we have grounds other than merely Pythagoras’ say so for believing the theory. If the only reason we had for believing the theory was that Pythagoras discovered it and people were claiming that this origin did not provide reliable grounds for accepting it then raising the origins would be valid.
So claiming that the origin of a certain belief provides reasons for thinking the sole grounds on which one holds it are unreliable, is not a version of the genetic fallacy.
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