Hacker News new | ask | show | jobs
by YeGoblynQueenne 780 days ago
>> Sorry about that, I'm dealing with a troll on another thread so I'm on a bit of a hair trigger.

Hey, no worries. Thanks for being a gentleman and I'm sorry you're being harassed. Btw, just to be clear: I'm perfectly fine with robust disagreement, I just don't deal well with personal attacks; which you didn't do, I was just worried that's where this conversation was going.

So, thanks for the very detailed analysis of your argument. That indeed makes it much simpler to find common ground. Here's where I disagree: point number 2!

Here's why. It's obvious to me that it's entirely possible to have two distinct models of the same process that compute almost identical results, so it's entirely possible for humans to be using a completely different process to catch balls etc, than kinematic equations.

And here's why I think this is likely: first, because of the point I made above about computational complexity and second because of the observed wide variability in the uh, let's say kinematic capabilities of different humans. If we were all solving kinematic equations, we would all have the same skills. What's more: humans can be wildly inaccurate in their motions (I know I am; don't leave coffee cups on my desk), while robots for example, are distinctly not. That also points to a different computation.

So, to summarise my argument: what we do needs neither be the same computational process, nor be computing the same results, as kinematic equations.

Btw, I'm a bit confused because I thought you were talking about kinematics in classical mechanics, but now I think you're talking about kinematics in robotics, with muscle actions etc. But I think both apply, except the robotics equations are I think much easier to solve than the classical mechanics ones, which I suspect may veer off into the chaotic.

Edit: I had more here on my _agreement_ to your point number 4, but I'm cutting it down to shorten the comment. You don't have all day :)

In any case, I think we just can't say for sure what our brains do, until we can say for sure.

1 comments

> it's entirely possible for humans to be using a completely different process to catch balls etc, than kinematic equations.

This all turns on what you mean by "completely different". Yes, obviously when you learn to actually catch a ball your brain is not doing anything that maps straightforwardly onto the kinds of symbolic manipulations that happen when you do math. On the other hand, it has to map onto doing math somehow even if that mapping is not straightforward. The only other possibility is that your brain is actually doing something that doesn't map onto math in any way, but still somehow produces the same results that math does by sheer coincidence. If you could actually demonstrate that, it would be one of the biggest breakthroughs in the history of science because it would refute the Church-Turing thesis.

To be honest I suspect the next scientific revolution would be a refutation of Church-Turing, or maybe something more like an extension of it to phenomena we are not closely studying yet, a bit like my understanding of the relation between Newtonian mechanics, and General Relativity and Quantum mechanics. Unfortunately that won't be me bringing that revolution about, so you won't get to say you exchanged views with a scientific legend :P

For the time being of course we can agree that our brains probably do some kind of maths, as far as we understand it. I'm guessing the way we understand maths has everything to do with the way our brains understand maths because, well, that's my position in our disagreement. But, see, I can do maths by counting on my fingers, so the question is really what kind of maths we're talking about and how complex can they realistically be. My argument is that if it's not the kind of maths a standard human being can calculate very quickly without pen or paper, then that's a no-go, because that leaves plenty of time to be eaten by a sabretooth, or what have you.

> I suspect the next scientific revolution would be a refutation of Church-Turing

I'll give you long odds against. That would be tantamount to discovering a physical phenomenon that could not be described mathematically.

> a bit like my understanding of the relation between Newtonian mechanics, and General Relativity and Quantum mechanics.

Those relationships are well understood: Newton is a low-order approximation of GR in the weak-field limit.

https://en.wikipedia.org/wiki/Post-Newtonian_expansion

The relationship between Newton and QM is explained, at least operationally if not philosophically, by decoherence:

https://en.wikipedia.org/wiki/Quantum_decoherence