Moore’s Law

The Accelerating Change conference last weekend began with an ill-formed debate between Ilkka Tuomi and Ray Kurzweil about the selection bias in data Kurzweil uses to “prove” Moore’s law. Arguing selection bias requires that we have a clear articulation of the theory we are testing. Is Kurzweil defending a guaranteed doubling of transistor density every 18 months indefinitely or is he defending something more general about compute power growing exponentially over time? Is the claim that compute power has been doubling every 18 months since the big bang and will do so until we enter a black hole or just that we are in a part of the production curve of computational technology that has this property? Without a fairly specific claim it is really hard to have any meaninful debate.

Is Moore’s law a natural constant like the speed of light, an artifact of US capital markets in the 20th century, or an emergent clock signal for a complex interdependent system in which a lot of independent actors need to coordinate in order to avoid substantial pain. Are there things we can do to speed this rate up or to slow it down? Personally, I favor the clock signal explanation. If chip performance were higher than expected, the chip manufacturers would face substantial economic loss because of bottlenecks later in the supply chain to the end customers. If the performance were lower than expected, the economic pain would be felt in the supply chain after the chip manufacturers. The number of parties required to coordinate for chip production/consumption is sufficienbtly large that the heartbeat becomes self-reinforcing.

The emergent clock signal explanation looks a lot like Milton Friedman’s explanation for inflation — it is a reflection of the expectations of market participants about the value of money (and that Intel perhaps plays the same role in the chip supply that the Fed plays in money supply). It implies that the chip industry is vulnerable to the same sorts of disruptions that affect the money supply. If the government decided that a moonshot chip was required, the heartbeat would accelerate. If the government deregulated spectrum, the heartbeat might decelerate as capital was devoted to new bandwidth technologies rather than microcomputer CPUs. If some new discovery changed investor priorities (e.g. concern about luddite terrorists attacking chip fabs or chip investors) or consumer priorities (e.g. a desire for more passive entertainment, failure to build reliable power plants, ….) then new chip fabs might not be able to get sufficient capital to keep up their current growth rate. Or at an absurd level, if life on earth got wiped out by an asteroid, would Moore’s law continue at the same rate? What is the claim that we are debating?

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One Response to Moore’s Law

  1. Ramez Naam says:

    I think it’s clear that Moore’s Law isn’t a “Natural Law”. As you pointed out, all sorts of disruption to society could hinder it.

    At the same time, the theory that it’s caused by the expectations of consumers and the coordination of members of industry doesn’t explain the fact that (at least according to Kurzweil) Moore’s Law held true for 70 or so years before anyone noticed it.

    My own vaguely formed thought is that there’s an economic relationship between:

    1) The value produced by X amount of computation.

    2) The amount resources that it’s rational to invest in future computational advances given point 1.

    3) The rate of computational advance produced by the resources invested in point 2.

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