Tag archives: Leonard Susskind

Leonard Susskind: a Darwinian physicist

By Matin Durrani

He probably won’t like me for saying this, but Leonard Susskind of Stanford University looks a bit like Charles Darwin.

The reason I know is that Susskind – one of the father figures of string theory – flashed up a slide of the great man (Darwin that is) during a public lecture last night held as part of the University of Bristol’s centenary celebrations and the city’s Festival of Ideas.

It was uncanny: Susskind’s grey beard and thinning hair make him a dead ringer for Darwin, who was born 200 years ago this year. I wonder if anyone’s told him of the likeness before?

Attended by nearly 700 people packed into the university’s neo-gothic Wills Memorial Building, Susskind’s lecture was entitled “Darwin and the cosmic landscape”, in which he examined Darwin’s influence on physics.

Susskind’s thesis is that by putting forward the then radical idea of a natural explanation of the origins of life, Darwin “set the standard for what an explanation should be like”. In other words, as Susskind eloquently explained, by rejecting the idea that life was too improbable too have arrived by accident and that there must be some sort of grand designer, Darwin instead sought a scientific explanation for the existence of life.

As Susskind pointed out, there are four different base pairs on a DNA molecule (A, G, C and T) and with each molecule having typically 10^8^ base pairs, there must be 4 to the power 10^8^ different ways of arranging those base pairs. Genetic mutations allow different arrangements, which – eventually – leads to the “tree of life”.

But what’s all this got to do with physics? Well, string theory permits the existence of a “landscape” of about 10^500^ different universes. We live on one of these universes – the one that permits the existence of life. It’s essentially an anthropic argument – the world is fine-tuned so we’re here to observe it.

I won’t go into the details here, but you can find all you need to know about this subject in an article by former Physics World features editor Matthew Chalmers, who also rolled up at last night’s lecture and was one of several people to pop Susskind a question.

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