gwern comments on 2012 Less Wrong Census Survey: Call For Critiques/Questions - Less Wrong

20 Post author: Yvain 19 October 2012 01:12AM

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Comment author: gwern 22 October 2012 03:43:55AM 3 points [-]

So let me get this straight. You can read PZ Myer's link, where he states in all serious

You’re just going to increase the speed of the computations — how are you going to do that without disrupting the interactions between all of the subunits? You’ve assumed you’ve got this gigantic database of every cell and synapse in the brain, and you’re going to just tweak the clock speed…how? You’ve got varying length constants in different axons, different kinds of processing, different kinds of synaptic outputs and receptor responses, and you’re just going to wave your hand and say, “Make them go faster!” Jebus. As if timing and hysteresis and fatigue and timing-based potentiation don’t play any role in brain function; as if sensory processing wasn’t dependent on timing. We’ve got cells that respond to phase differences in the activity of inputs, and oh, yeah, we just have a dial that we’ll turn up to 11 to make it go faster.

The comments call him out on it in the original post at http://freethoughtblogs.com/pharyngula/2012/07/14/and-everyone-gets-a-robot-pony/ and he stands by it. And you're worried about information cascades on LessWrong?

(Incidentally, in a post on GRG, it was mentioned that the first mouse brain is being examined by the Brain Preservation Prize are showing preliminary signs of excellent fixation, specifically "perfectly preserved ultrastructure throughout the brain".)

Comment author: John_Maxwell_IV 22 October 2012 04:15:34AM *  2 points [-]

I did find that objection less persuasive. I didn't say PZ's post was perfect.

I don't think doing rationality better than PZ should be our goal; I think figuring out what's true should be our goal. I do think that semi-ridicule by a professional biologist should be taken as evidence that the authors of WBE roadmap know less than they think (edit: but see Carl Shulman's comment). Beyond that, I'm out of my depth and happy to be corrected on specifics.

Comment author: fubarobfusco 22 October 2012 07:56:19AM 5 points [-]

Argument screens off authority. When an esteemed biology writer dismisses a claim about computer simulations of life-forms by using an argument based on a serious confusion regarding computation (not regarding biology), his reputation as a biologist counts for nothing.

Any computer simulation can be run faster than real-time given adequate processing power; and this has nothing to do with whether the process being simulated can be accelerated.

Comment author: John_Maxwell_IV 23 October 2012 12:31:04AM *  2 points [-]

Myers writes:

Sure, you can just arbitrarily set the time-scale of the simulation, but then you mess up the inputs from outside the simulation. And you can’t model a human brain in total I/O isolation without it melting down into insanity.

I didn't feel comfortable dismissing his objection out of hand, because I wasn't exactly sure what point he was trying to make. Then I read Carl Shulman's comment, and now I'm thinking it probably just didn't occur to him to simulate the brain in a sped-up virtual environment. Probably he assumed the simulation was expected to interact with the real world as flesh-and-blood humans do, just while thinking faster. If this was the goal, it seems his objection would be valid.

Comment author: fubarobfusco 23 October 2012 02:42:55AM 0 points [-]

Fair enough. His point that a mind works with sense organs is a good one, it's true. Running a double-speed brain with single-speed audio inputs w...o...u...l...d ... n...o...t ... w...o...r...k.

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