Rationality Quotes June 2013

Thomas

Another month has passed and here is a new rationality quotes thread. The usual rules are:

Please post all quotes separately, so that they can be upvoted or downvoted separately. (If they are strongly related, reply to your own comments. If strongly ordered, then go ahead and post them together.)
Do not quote yourself.
Do not quote from Less Wrong itself, Overcoming Bias, or HPMoR.
No more than 5 quotes per person per monthly thread, please.

Another month has passed and here is a new rationality quotes thread. The usual rules are:

Please post all quotes separately, so that they can be upvoted or downvoted separately. (If they are strongly related, reply to your own comments. If strongly ordered, then go ahead and post them together.)
Do not quote yourself.
Do not quote from Less Wrong itself, Overcoming Bias, or HPMoR.
No more than 5 quotes per person per monthly thread, please.

I will gladly post the rest of the conversation because it reminds me of question I pondered for a while.

"Do you understand the tides, Colonel Barnes, simply because you know to say ‘gravity’?”

“I’ve never claimed to understand them.”

“Ah, that is very wise practice.”

“All that matters is, he does,” Barnes continued, glancing down, as if he could see through the deck-planks.

“Does he then?”

“That’s what you lot have been telling everyone. <> Sir Isaac’s working on Volume the Third, isn’t he, and that’s going to settle the lunar problem. Wrap it all up.”

“He is working out equations that ought to agree with Mr. Flamsteed’s observations.”

“From which it would follow that Gravity’s a solved problem; and if Gravity predicts what the moon does, why, it should apply as well to the sloshing back and forth of the water in the oceans.”

“But is to describe something to understand it?”

“I should think it were a good first step.”

“Yes. And it is a step that Sir Isaac has taken. The question now becomes, who shall take the second step?”

After that they started to discuss differences between Newton's and Leibniz theories. Newton is unable to explain why gravity can go through the earth, like light through a pane of glass. Leibniz takes a more fundamental approach (roughly speaking, he claims that everything consist of cellular automata).

Daniel: “<...> Leibniz’s philosophy has the disadvantage that no one knows, yet, how to express it mathematically. And so he cannot predict tides and eclipses, as Sir Isaac can.”

“Then what good is Leibniz’s philosophy?”

“It might be the truth,” Daniel answered.

I find this theme of Baroque Cycle fascinating.

I was somewhat haunted by the similar question: in the strict Bayesian sense, notions of "explain" and "predict" are equivalent, but what about Alfred Wegener, father of plate tectonics? His theory of continental drift (in some sense) explained shapes of continents and archaeological data, but was rejected by the mainstream science because of the lack of mechanism of drift.

In some sense, Wegener was able to predict, but unable to explain.

One can easily imagine some weird data easily described by (and predicted by) very simple mathematical formula, but yet I don't consider this to be explanation. Something lacks here; my curiosity just doesn't accept bare formulas as answers.

I suspect that this situation arises because of the very small prior probability of formula being true. But is it really?

10DanArmak13y

Stanislaw Lem wrote a short story about this. (I don't remember its name.) In the story, English detectives are trying to solve a series of cases where bodies are stolen from morgues and are later discovered abandoned at some distance. There are no further useful clues. They bring in a scientist, who determines that there is a simple mathematical relationship that relates the times and locations of these incidents. He can predict the next incident. And he says, therefore, that he has "solved" or "explained" the mystery. When asked what actually happens - how the bodies are moved, and why - he simply doesn't care: perhaps, he suggests, the dead bodies move by themselves - but the important thing, the original question, has been answered. If someone doesn't understand that a simple equation that makes predictions is a complete answer to a question, that someone simply doesn't understand science! Lem does not, of course, intend to give this as his own opinion. The story never answers the "real" mystery of how or why the bodies move; the equation happens to predict that the sequence will soon end anyway.

5ChristianKl13y

I think the situation happens because of bias. Demonstrating an empirical effect to be real takes work. Finding an explanation of an effect also takes work. It's very seldom in science that both happens at exactly the same time. Their are a lot of drugs that are designed in a way where we think that the drug works by binding to specific receptors. Those explanations aren't very predictive for telling you whether a prospective drug works. Once it's shown that a drug actually works it's often that we don't fully understand why it does work.