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Comment by sudo_bang_bang | Hacker News Reader

"The human brain, which accounts for less than 2 percent of the body’s mass, uses 20 percent of its calorie budget, or three bananas worth of energy a day. That’s remarkably low, given that spikes require a lot of energy."

What is amazing about this fact is that this is only 20 watts of power. The brain computes at 10 quadrillion calculations per second. While the largest supercomputer (China’s Tianhe-2) is at 34 quadrillion and has "beat" the human brain, it comparatively runs at 24 megawatts of power [1]

[1] http://waitbutwhy.com/2015/01/artificial-intelligence-revolu...

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Yes! This was the biggest flaw in The Matrix (which I otherwise love): it had machines using human bodies as power sources whereas they could have used human brains for computational power leading to huge power efficiency.

Think about somehow hooking up a brain to a computer which can interpret the neural code. Then you have the best known general purpose AI machine running on 20W. Now combine hundreds, thousands of them. Not human brains, of course, but say monkey brains. DARPA already conducted some experiments in this area (http://www.kurzweilai.net/darpa-links-brain-waves-sensors-an...)

>it had machines using human bodies as power sources whereas they could have used human brains for computational power leading to huge power efficiency.

That was apparently the original intent, that the Matrix used human brains as a neural net. But the script was changed to "humans = batteries" because of fears audiences wouldn't be able to comprehend it[0].

[0]https://scifi.stackexchange.com/questions/19817/was-executiv...

The brains-as-the-Matrix conceit would have been much more powerful. Damn. Lots of symbolic value, and a statement on human culture, human nature, and complacency vs. untapped potential.

I'm going to go ahead and pretend that's what actually happens. :)

It is possible that when Morpheus described the 'true purpose' of the Matrix, he didn't actually know what he was talking about. I think that's the excuse most people use. It was a best guess based on piecemeal information (and possibly deliberate misinformation by the machines.)

Not actually canon but it'll do.

Perhaps it is a misunderstanding on the part of the humans in the film. They could be mistaking the human brains powering the neural network by means of providing processing capacity for powering it by means of providing energy.

Thanks for the link, fascinating discussion in these answers. I found this very relevant to this point: http://scifi.stackexchange.com/questions/12223/why-did-the-m.... One other problem with the humans as batteries thing (in addition to its inelegance) is that the machines could have used cows or pigs to much better effect.

This comment wraps it up nicely: "All the machines ever wanted was to be left alone, not destroy humanity. I suppose this is the most humane solution they could think of"

Brains don't do FLOPS. It is a completely different type of "calculation". Computational benchmarks are only directly comparable when the representations of input and output are the same.

That's very true, but in some ways it's even more remarkable: there exists an alternative form of calculation/computation that is "magical" in certain domains when compared to all the standard CS we know, and we don't have a clue what it is.

It's not an apple/apple comparison. It's an apple/unicorn comparison.

I don't know, if counted every modulation in every wire in a computer (CPU, RAM, cache activations, etc), you might get a signifant multiple of its FLOPS count, right?

> 10 quadrillion calculations per second

What exactly is that based on? Does it count anything other than synapses?

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