Nonsense on Stilts: How to Tell Science from Bunk

Popper and falsification are representative of a somewhat prescriptive steak in philosophy of science, that is, of a tradition of philosophers actually telling scientists how they ought to carry out their work. As we have seen, Popper was motivated by the so-called demarcation problem--the difficulty in distinguishing science from non- and pseudoscience--the very issue that is central to this book. He was also bothered by Hume’s problem of induction, and yet the only reason we have to trust induction is because it worked in the past (which is itself a form of induction, making the whole thing perilously close to being circular).

Scientific practice requires the assumption of naturalism, that is, the idea that natural phenomena are, well, natural, and therefore scientists do not need to invoke the supernatural to explain them. In fact, we noted that scientists themselves invoke naturalism as a postulate of science whenever they need to make the (convincing) argument that the so-called theory of intelligent design is not science because of its supernatural basis. The important thing to realize is that in the context of our discussion naturalism is not an empirically verifiable position, and it is therefore by definition outside of science itself. If science is about anything at all, it is about empirically verifiable statements concerning the world.

Now here is a comment, quoted by Sokal, that Latour made on Einstein’s theory of relativity, in which he takes to task “[Einstein’s] obsession with transporting information through transformation without deformation; his passion for the precise superimposition of readings; his panic at the idea that observers sent away might betray, might retain privileges, and send reports that could not be used to expand our knowledge; his desire to discipline the delegated observers and to turn them into dependent pieces of apparatus that do nothing but watch the coincidence of hands and notches.” This would be comical if it weren’t such a sad example of the misunderstanding of science by a nonscientist. First of all, Latour is criticizing a popular book by Einstein, not a technical article, presumably because Latour simply cannot understand a technical paper in fundamental physics (full disclosure: nor can I, nor most people living on the planet—but some of us try not to write commentaries about things we do not understand). More importantly, Einstein was explaining his theory through a thought experiment, using hypothetical human observers to help describe the nuances of the concept. Latour’s talk of “panic,” “betrayal,” and “privileges” is complete emotive nonsense. This is physics, not a Shakespearian tragedy.

Physicists recognize three more forces in nature (other than gravity): the strong and weak nuclear interactions, and electromagnetism. That’s it--there are no other known physical forces to play with. We can exclude the strong and weak nuclear forces, because they can only be effective at the scale of atomic or subatomic, not astronomical, distances. Electromagnetism is a more promising candidate, but only at first glance. Again, this is something that science has studied for a long time, and we can measure the electromagnetic fields of the various planets and of the sun. Turns out that the latter is the only one that has any significant effect, as can be seen every time that there is a solar magnetic storm, a phenomenon capable of interfering with our communications and in some cases even causing blackouts in major cities. But if electromagnetism is the conduit of the astral influences than astrology should be based just on the sun--forget the moon, planet, and other stars. Clearly, that is not compatible with astrological practice.

It is always possible for the astrologer to retreat one step further and claim that astral influences are mediated by a fifth, yet undiscovered force. We cannot be certain that there is no such thing as a fifth force, but everything that has happened in theoretical and experimental physics over the past century indicates that there are only four fundamental forces...moreover, even if there were a fifth force, it would appear logical to assume that—like every force known so far—its action too depends on distance, meaning that the further away two objects are the less strength force X will have. If this is the case, then astrologers would still not be out of the woods, because they insist on treating all planets as having the same influence on human affairs, regardless of distance. This means that not only do they have to assume the existence of a fifth force, which is improbable enough, but also that this would be the only force whose action does not decrease with distance, thereby piling improbability upon improbability.

It is certainly true that “Darwin’s theory is a theory,” in the same way that it is true that my chair is a chair, that is, by definition (notice, incidentally, that just like modern mechanical physics is not “Newton’s theory,” the modern theory of evolution is not “Darwin’s theory,” but a more advanced and sophisticated theory known as the Modern Synthesis). Second, the theory is not a fact, again, by definition. Scientific theories are just what the board states they are: explanations meant to unify a broad range of observations. Facts are observations that the theory attempts to make sense of, which is why the standard creationist refrain that “evolution is a theory, not a fact” is at the same time (almost) correct and yet entirely irrelevant. Moreover, the business about gaps in the theory “for which there is not evidence” betrays a profound misunderstanding of the nature of scientific theories: every theory has “gaps,” meaning sets of facts that are not (currently) explained by the theory, or conversely, makes hypothetical statements that are not (currently) supported by empirical evidence. This is true for evolution, quantum mechanics, general relativity, or whatever. Theories are human constructs meant to guide our understanding of nature, and as such have always been and will always be “incomplete.” Once one realizes that this is a normal condition of science, it will not come as a surprise that the theory of evolution has “gaps.”

Perhaps the most elegant and devastating critique of the Aristotelian conception of physics was made by Galileo through a thought experiment[citation omitted]: Aristotle had claimed that bodies fall at a speed that depends on their weight, the heavier bodies faster than the lighter ones. Galileo therefore invited his readers to consider a situation in which a heavier and a lighter body were joined by a cord and were falling together. According to Aristotelian physics, the heavier one should drag the lighter one down faster so that the combined body would have a higher speed than the lighter by itself. Then again, by the same Aristotelian theory, the lighter body would be expected to slow down the heavier one, so that the combined bodies would fall at a slower speed than the heavy body by itself. The punchline is that the first prediction is logically contradictory to the second one: one cannot be true without the other one being false, and yet Aristotle would have to admit that both stem out of his conception of bodies and speed. Ergo, Aristotle’s conception of bodies and speed must be wrong. One can imagine the ancient Greek nodding approvingly at the genius of the Italian scientist and admitting defeat. Although common lore wants it that Galileo, being a good scientist, actually performed the experiment by dropping different weights from the tower in Pisa, there is much historical doubt that he actually did.