Dear reader,

how many times have you said, “It’s just a theory, in practice it’s different”? I’m sure you meant it wholeheartedly.

This sentence has always had, at least for me, a strange sound to it: what’s then the purpose of making theories, if we know practice¬†is just different? Shouldn’t we then just make… a different theory? Or should we just stop making up theories altogether and live a less worrisome life?

The point is that… we all know, somewhere inside ourselves, that theories work!

We split the atom (quantum field theory), went to to the moon and back (chemistry, computer science, physics and a lot more), we use GPS every day (general relativity), behavioural economics is used successfully everywhere (even if we are not much conscious about it).

So, are theories worse or better than whatever it is that we call “practice”?

I think the problem is how we apply the former and look at the latter.

A theory is not something you “put over” your problem as-is:

  • “Look, this is chemistry! So, this is the equation, and this is the result!” And then you go BOOM, and you don’t know why!
  • “Look, this is physics! The projectile should pass there!” And then no, you are not William Tell.
  • “In theory, I should play this chord!” And it sounds horrible.

No: applying a theory this naive way it’s just a first order approximation. You probably need to do more calculations, take into account more facts, but you mustn’t disregard theories as incomplete. In the example above, maybe you did not take into account the fact that you were not in a vacuum, or at 1 atmosphere of pressure, that your becker was dirty, that a projectile is not point-shaped and that the guitar has some frets slightly out of tune in some positions.

On the other hand we should keep in mind that practice is the full (yet unknown) “Theory of Everything” on display: everything we see is the ultimate experiment design to find the outcome of the situation at hand, and it’s, tautologically and by design, guaranteed to work out as it is supposed to work out. So it’s natural that we are biased toward experience: it’s always accurate and always turns out as it should. Thanks to our deep-rooted hindsight bias we find a lot easier to explain backwards rather than predict forward.

So, here is what I usually do: I try to rely on sound theories, and I’m always on the lookout for seemingly inexplicable facts and missing assumptions. I don’t disregard the outcome of practice; I learn from it if I can! Even if I don’t have an explanation for what I observe, I’d be a complete fool to disregard it as wrong because it doesn’t go by the book!

Until next time, in theory, I’ll try to write more posts, but practice is different…