Why-questions are dirty

I will share in this Blog some reflections on Physics (and in particular Special Relativity) that I also post in www.physicsforums.com, although here I will also be including comments on broader topics.

I intend to publish only ideas that are as widely acceptable and as little speculative as possible, but I do not guarantee that the scientific parts of this site are reliable, since I am no authority in this field.

The title of this first entry gives the tone of the series. I am addressing why-questions, admitting (half-jokingly) that they are "dirty"... because, yes, that has been the conclusion of a recent discussion in Physics Forums: to ask "why" is legitimate, but it simply means focusing on the details of a process, getting your hands dirty with the mechanics.

I have often complained, with regard to a number of Special Relativity issues, that the standard solution simply resorts to Einstein's postulates: this is so and so because the Principle of Relativity so requires, for example. I thus cried: that amounts to describing how nature works, but not explaining why it works that way. I was responded: you will find no scientific explanation that is not purely that, a description of how nature works.

When confronted with this answer, I was struck by my own complaint. I had written many pages defending the opposite of what I had just affirmed. I have been even more radical. I hold that we do not even describe nature. We interact with nature, we annotate the score of this sort of fight (we measure) and we interpret our measurements as clues for solving day-to-day problems. That is all.

What happened, then? Why did I speak against my conviction? I am afraid that the same thing happened as with my tennis. I have learnt new tricks, but in the heat of a game or a discussion, my doggish mind seeks refuge in the old routines. Realizing this helped me the trouble of losing energy in a useless fight. But I did feel that my complaint had "some" justification. So I decided to re-phrase it. I like semantics and I trust it is a powerful tool that can bring you out of a lot of trouble, both in life and in intellectual discussions.

Thus in the end we found an understanding.

I admitted that axioms like the Principle of Relativity cannot be labelled as "less profound". You cannot say that they must be put aside in favour of purportedly "deeper" truths. Granted: the more abstract that a principle is, the better it is. First, because it is beautiful in its slimness, which is the same as saying that it (probably) works. (We like handsome people because they were more apt to survive in old times. A different thing is that such evolutionary advantage may be useless today. But the idea still holds in the intellectual realm.) Second, a very elementary, fundamental principle is like a magic word, a master key that you can take anywhere to opens myriads of doors.

Yet I also found a better expression for my concern. I just wanted to descend to the details. Zoom in. Put on the working costume and stain my hands with the intricacies of the process in question, whatever it is. The helicopter view is necessary, but sometimes it is also convenient to turn into a little insect that dwells, with the devil, amongst the details. To sum up: the infamous why-questions do not lead you to a "deeper", but to a "lower" level.

I trust that this approach may be fruitful. My opponent in the discussion (now somehow siding with me…, though not for long: he is a tough guy!) commented that this way you often find connections between thing that might look unrelated before. I expect so. In particular, I intend to touch these issues, in the field of Special Relativity: why does the mechanical clock time-dilate, why does the photon hit the target in the light clock experiment, what is spacetime, why - to the dismay of book-sellers - nothing, not even faster than light travel can violate causality...?

It is not that I will always be so poetical. I promise some math and some geometry as well. But, yes, literature will be here, I will talk about Cinderella and the slipper. And I will also talk about law: when you look at the practical details, you realize that Einstein's theory is very "legal", very much in the line of that dirty art… lawyer's reasoning!