Comment by dkarl | Hacker News Reader

Comment by dkarl | Hacker News Reader

Animals, which move, have limbs and muscles. The earth does not have limbs and muscles; therefore it does not move.

I wonder if this sounded as dumb back then as it does now? What about things that do not move under their own power, yet move nonetheless, such as waves and wind? What about flowers that close every night and open in every morning? What about the fact that they knew almost nothing about the earth deeper than the tiniest scratch on its surface -- perhaps there are muscles of a sort under there?

What about the "fact," as they would have seen it, that God can make anything move however he wants, and that he might have a special mechanism that makes planets and stars move but does not apply the same way to things on Earth? And did he really believe that the moon and stars have limbs and muscles?

I think this illustrates how people can get away with any possible idiocy as long as they are on the right side of an issue. This is why scientists care about the timing of publication: they look a lot more competent if they publish their results at a time when everyone will tend to believe they are correct, instead of at a time when everyone will pick their paper apart looking for flaws (or simply assume the flaws are there.)

Although I cannot find the original text, I expect the word "move" is not a precise translation because he goes on to say:

> Animals, which move, have limbs and muscles; the earth has no limbs or muscles, therefore it does not move. It is angels who make Saturn, Jupiter, the sun, etc., turn round. If the earth revolves, it must also have an angel in the centre to set it in motion; but only devils live there; it would therefore be a devil who would impart motion to the earth....

> The planets, the sun, the fixed stars, all belong to one species - namely, that of stars. It seems, therefore, to be a grievous wrong to place the earth, which is a sink of impurity, among these heavenly bodies, which are pure and divine things.''

A sink of impurity. There's a data point that has lasted through the ages.

A sink of impurity. There's a data point that has lasted through the ages.

I wonder, then, why he didn't find it plausible that it is devils or fallen angels who move the earth?

This statement is a clear and obvious logical fallacy, and should have appeared as such to contemporary audiences. He is saying that Animals have (limbs => they move) => (the Earth does not have limbs => it does not move). But the latter is the inverse of the former, which must be proven separately and which is not implied by the conditional.

As I commented below, I expect the translation "move" makes it sound worse than it did in the original. If he means "are self-propelled" or "are mobile", it's slight less wrong.

That's correct.

Nonetheless, we can certainly grant him an implicit "Only living things (animals) can move (by themselves)." Doesn't make it any less wrong, but I doubt that it's just a logical fallacy.

It's hard to know the tone and context of the statement in its era. Perhaps it was simply a philosophical statement about God's intentions; perhaps it was meant to be a little tongue-in-cheek; perhaps it was mis-translated.

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