Q&A: A Layman’s Question in Physics
A Layman’s Question in Physics
Question
Hello, our Rabbi…
A Chabad fellow wrote to me in response to the mockery I made of the interpretation of the Rebbe of Shiloh in the Books Trial. He argued that when a great person says strange things, we should humbly believe him that it is a correct idea, because we do not understand everything. As a response, I want to write in “Drops of Sanity” that nonsense remains nonsense even if it is said by a great person [there is a difference between not understanding and understanding that it is not so]. When there are two sides and both have some logic to them, I will rely on someone who understands more than I do that the side he holds is more correct, even if I think the opposite, because his intuition is better than mine. But when it is clear to me logically that it is nonsense… etc.
[I’m still wondering how to relate to things that seem logically absurd to me, but people claim that this is the reasoning in Kabbalah, which I do not understand, yet it still remains nonsense.
But I am uncertain: quantum theory, to my mind, sounds completely absurd. Is that only because I lack explanations or logical preliminaries in physics, or is it still a theory that does not fit our logic, but is necessary because that is what laboratory experiments reveal and there is no other explanation except to recognize the fact that there are things in nature that are plainly illogical? That is, did the first people who discovered quantum theory arrive at these conclusions because that is what made sense to them, and only afterward check in the lab and find that this was indeed the case? Or the opposite: they found phenomena in the lab that were plainly illogical, but the experimental results showed that this is how it is — meaning, there are laws of nature that we have no logical grasp of at all. If it is the first side, then one could say that when a person I believe to be a great man says something foolish, perhaps it is not foolish, but rather my logic is not sufficiently developed.
I would appreciate your reply.
Answer
Rabbi D., hello.
It really is that illogical, to the point that it is clear that all the pioneers of quantum theory arrived at it through experiment and not through reasoning alone. The findings that had accumulated up to then, and since then as well, lead us to this strange theory. Not for nothing did Michio Kaku (a Japanese physicist) say about it: quantum theory is the most illogical theory in the world. It has only one drawback — it works / it is true.
But contrary to what many people think (including experts), there is no logical contradiction in quantum theory (nor any departure from our logic). The reason for this is very simple, and twofold:
1. We arrived at these findings themselves on the basis of our own logic. If our logic is not correct, then quantum theory is not correct either. In other words: if there is no longer any logic, then when quantum theory says X, you can also say simultaneously “not X.”
2. There is a theorem in mathematics/logic that from a system that contains a contradiction, one can infer anything whatsoever (in other words: it says nothing). But from quantum theory you cannot infer just anything, and it definitely has factual-empirical content. From this it follows that it contains no logical contradiction. Which is what had to be proved.
Quantum theory contradicts our intuition, but not logic. Intuition (reasoning/common sense) is an important thing (I have written several books about it), but it is not absolute. It should be treated with respect, but not with reverence. Therefore it is important to test intuitions empirically. Aristotle had the intuition that bodies fall to the ground at a speed proportional to their mass. To test this (and discover that it is of course not correct — they all fall at the same speed regardless of mass), you do not need particle accelerators, just two stones and a high place, and yet it never occurred to him to test it empirically. From his point of view, why would I need a verse when reasoning says it already?! So modern science teaches us that reasoning is not always correct. One must be careful with our intuitions and test them against the facts.
Of course, everything I have written here refers to “logic” in the sense of necessary formal (mathematical) logic. Logic in the sense of plain “making sense” (which is probably what the term means for you) is nothing but intuition, and above I already explained the proper attitude toward it. Thus, for example, all the paradoxes of the red heifer involve no logical contradiction at all, but at most something incomprehensible. One must be very careful in using the term “logic” — and that itself is a logical claim.