The great physicist Richard Feynman once opened a seminar with this profound but amusing stand-up routine: “Einstein was a giant.” [long pause] “His head was in the clouds but his feet were on the ground.” [long pause] “But those of us who are not that tall have to choose!” [universal laughter]. Among his audience was another of my heroes, Carver A Mead, who’s definitely chosen to keep his feet on the ground, while never quite losing sight of the clouds.
Mead, now professor of engineering and applied science at Caltech, has possibly better claim than anyone to be the father of the electronics revolution. A former student of Feynman’s, in 1968 he delivered a highly original lecture on the scaling properties of semiconductor devices in answer to a question raised by Gordon Moore (yes, that Gordon Moore, working at Fairchild Semiconductor). Moore went on to found Intel and turn those properties into the chips that drive our PCs. Mead laid the theoretical basis for said chips, using his profound knowledge of quantum physics.
It’s almost impossible to imagine Great Britain ever breeding a Carver Mead. His father was an electrical engineer who worked on the great hydro-electric projects of the Roosevelt era: he grew up in a “camp” by a dam in California’s Sierra mountains, occupied entirely by electrical engineers and their families. By the time he was 12, electrons were as real to him as marbles, and he went straight from high school to Caltech, where he’s worked now for 50-odd years.
His Introduction to VLSI systems (written with Lynn Conway) is The Most Important Book Of The 20th Century That No-one’s Heard Of. In it, he lays out the principles for making all the chips we now use, plus a couple of generations we haven’t started to make yet.
In recent years, Mead has turned his attention to the way biological systems process data, and how to emulate them in silicon. A friend of mine used to work next door to him at Caltech and watched an analogue artificial retina chip he was developing in action. It uncannily reproduced the behaviour of the human eye by saturating if it looked at the same spot for more than a second, so it had to be randomly twitched to keep on seeing.
More recently still, Mead has focused his own eyes back on the clouds. In Collective Electrodynamics, he set out on an apparently quixotic quest to overthrow the Copenhagen Interpretation of quantum mechanics. That’s the version put forward by Niels Bohr, the version everyone knows a little bit about, where particles can be in two places at once (but you can’t know exactly where) and where the whole universe becomes a fuzzy and indeterminate place. Bohr’s interpretation triumphed in the late 1920s against the alternative views of Einstein and Schrodinger, who were appalled at the introduction of statistical uncertainty at such a fundamental level (“I cannot believe that God plays dice…”).
Mead agrees with Einstein that statistics have no place at the bottom level of physics: they don’t reflect physical reality but merely our problems about knowing that reality. He bases this belief on the fact that several important phenomena have been discovered since those great Einstein-Bohr debates (he helped discover some of them), which, if known then, would have altered the outcome. These include superconductivity, lasers, the Quantum Hall effect and the Bose-Einstein condensate, and they all share one property – they involve the behaviour of coherent wave systems. Mead proposes that to understand the fundamental properties of matter, you must start from the properties of coherent waves – the exact opposite direction from the Copenhagen approach, which needs its statistical and probabilistic methods because it starts from incoherent phenomena.