I’m Michael “Valentine” Smith. Cofounder & senior instructor at CFAR 2012–2018. I left the rationality scene 2018–2024 to do some soul-searching. I’ve now reentered the fray, hopefully a bit wiser but that’s not really mine to judge.
You can find my non-LW writing on my blog Relentless Dawn. You can also find my social media profiles via my Linktree (though I mostly post on Twitter, and basically not anywhere else).
As long as we’re going to do this tangent:
Aristotelian physics is less constrained than Newtonian physics. That’s the main reason it works. Anything you can explain with Newtonian physics, you can explain with Aristotelian physics too.
(...for the most part. I haven’t done a thorough logical check that this statement is strictly true. But it’s true enough. Both theories can explain why the path of a projectile is a parabola for instance.)
The “Anything you can explain with X, you can also explain with Y” thing is also true of more accurate or general theories. Anything Newtonian physics explains, so does Einsteinian physics.
The key thing (IMO) that makes Aristotelian physics inferior is that it also can explain false things.
For instance, it’s a priori possible that the arc of a thrown rock is a segment of a circle. If so, we could explain that in Aristotelian terms: motion is naturally circular, as demonstrated by the heavens (the sphere of quintessence), so of course the way something thrown away from its natural sphere would return to it via a circular motion.
But had thrown rocks formed arc segments instead of parabolic segments, that would have invalidated Newtonian (and Einsteinian) physics.
So the key thing that makes Newtonian physics a better theory than Aristotelian is that it’s more constrained and still survives experimentation. The theory literally has more Shannon information in it. That’s why Newtonian mechanics let us build the Iron Bridge in one shot whereas Aristotelian physics couldn’t: it wasn’t constrained enough to tell us what would happen with different bridge designs even after knowing everything about iron’s physical properties.
It’s a case where science made advancement without directly falsifying a theory.
So sure, Aristotelian physics was mostly right, in the sense that it was and is a fit to how the world works. It’s just that Newtonian physics also fits, and is more constrained, which means it’s the more useful fit to our world.
(This message brought to you by, taking a break from coding with LLM agents, and sadly noticing that some of their cadences have affected my way of talking. Alas. I just need to write more of my own stuff I suppose.)