Free What If? by Randall Munroe Page A

computing power than existed in the entire world in 1965. By that measure, the year when the combined power of computers finally pulled ahead of the combined computing powerof humans was 1977.
    The complexity of neurons
    Again, making people do pencil-and-paper CPU benchmarks is a phenomenally silly way to measure human computing power. Measured by complexity, our brains are more sophisticated than any supercomputer. Right?
    Right. Mostly.
    Th ere are projects that attempt to use supercomputers to fully simulate a brain at the level of individual synapses. 5 If we look at how many processors and how much time these simulations require, we can come up with a figure for the number of transistors required to equal the complexity of the human brain.
    Th e numbers from a 2013 run of the Japanese K supercomputer suggest a figure of 10 15 transistors per human brain. 6 By this measure, it wasn’t until the year 1988 that all the logic circuits in the worldadded up to the complexity of a single brain . . . and the total complexity of all our circuits is still dwarfed by the total complexity of all brains. Under Moore’s law­–based projections, and using these simulation figures, computers won’t pull ahead of humans until the year 2036. 7
    Why this is ridiculous
    Th ese two ways of benchmarking the brain represent opposite ends of a spectrum.
    One, the pencil-and-paper Dhrystone benchmark, asks humans to manually simulate individual operations on a computer chip, and finds humans perform about 0.01 MIPS.
    Th e other, the supercomputer neuron simulation project, asks computers to simulate individual neurons firing in a human brain, and finds humans perform about the equivalent of 50,000,000,000 MIPS.
    A slightly better approachmight be to combine the two estimates. Th is actually makes a strange sort of sense. If we assume our computer programs are about as inefficient at simulating human brain activity as human brains are at simulating computer chip activity, then maybe a more fair brain power rating would be the geometric mean of the two numbers.

    Th e combined figure suggests human brains clock in at about 30,000 MIPS — right about on par with the computer on which I’m typing these words. It also suggests that the year when Earth’s digital complexity overtook its human neurological complexity was 2004.
    Ants
    In his paper “ Moore’s Law at 40,” Gordon Moore makes an interesting observation. He points out that, accordingto biologist E. O. Wilson, there are 10 15 to 10 16 ants in the world. By comparison, in 2014 there were about 10 20 transistors in the world, or tens of thousands of transistors per ant. 8
    An ant’s brain might contain a quarter of a million neurons, and thousands of synapses per neuron, which suggests that the world’s ant brains have a combined complexity similar to that of the world’s humanbrains.
    So we shouldn’t worry too much about when computers will catch up with us in complexity. After all, we’ve caught up to ants, and they don’t seem too concerned. Sure, we seem like we’ve taken over the planet, but if I had to bet on which one of us would still be around in a million years — primates, computers, or ants — I know who I’d pick.

    1 Except Red Delicious apples, whose misleading name is a travesty.
    2 Our house had a lot of vases when I was a kid.
    3 Yet.
    4 Th is figure comes from a list ( http://www.frc.ri.cmu.edu/users/hpm/book97/ch3/processor.list.txt ) in Hans Moravec’s book Robot: Mere Machine to TranscendentMind .
    5 Although even this might not capture everything that’s going on. Biology is tricky.
    6 Using 82,944 processors with about 750 million transistors each, K spent 40 minutes simulating one second of brain activity in a brain with 1 percent of the number of connections as a human’s.
    7 If it’s past the year2036 right now while you’re reading this, hello from the distant past! I hope things are better in the future. P.S. Please figure out a way