Skip to main content

The Goldilocks Enigma – Paul Davies ****

The anthropic principle, depending on whom you believe, is either the most profound idea in cosmology or a load of old hokum. Essentially the principle says that the universe has to be the way that it is otherwise we would not be here to observe it in the first place. This may at first glance appear to stating the obvious – but this idea has very deep implications about our universe.
In particular, some cosmologists have appealed to the principle to help explain what is know as the fine tuning problem. The constants of nature such as Planck’s constant, the speed of light, the universal gravitational constant, etc. have very precise values, in fact if some of these constants were even slightly different (i.e. to the nth decimal place) then the physical nature of our universe would be radically different to what it is. Stars, galaxies and in fact life itself would not be able to exist in such conditions. The problem is, of course, why these constants should have values that have made our universe so hospitable to life.
This is a question that science authors have written about before, most notably Martin Rees’ two superb books: Just Six Numbers, and Our Cosmic Habitat. These two books put forward the hypothesis that we live in a multiverse – where the constants of nature have all possible values – leading to some universes being hospitable to life like ours, and others being completely unfriendly to life.
Davies’ book is far more ambitious and sweeping in providing an overview of the anthropic principle than Rees’ work. He considers several explanations including the possibility that we live in a computer simulation, an infinite sea of ‘habitable regions’ in a single universe as predicted by inflation theory, and the possibility of the universe obeying a self organizing principle. The most remarkable suggestion though is Davies own idea that revolves around the delayed choice experiment.
A thought experiment first proposed by John Wheeler, this is a variation of the famous double-slit experiment, except that the detector screen can be removed at the last moment, directing light into two remote telescopes, each focused on one of the slits. In a conventional double-slit experiment, the light acts as waves, causing interference patterns, if no check is made as to which slit a photon goes through, but acts as individual, non-interacting photons if the photons’ paths are checked. In Wheeler’s version there is a ‘delayed choice’ for the observer, not making the decision on which way to observe until after the light has passed the slits. Physicists are currently working on a real version of this experiment, and in fact Wheeler himself suggested an astronomical equivalent of his delayed choice set up – which may give observational weight to his idea.
Davies suggests that our universe may well operate in a similar ‘delayed choice’ manner and that the observations we make now have retroactively fixed into place the constants of nature which existed in a ‘fluid’ state shortly after the big bang.
Unfortunately the material that gets to the heart of the book’s subject matter only takes up its second half. The first half is a very readable account of the current state of big bang cosmology and how it leads to the anthropic principle, but readers who are familiar with these ideas may find the first half of the book a little long winded. Nevertheless this is an excellent read, though some might find Davies’ own ideas at the end of the book a bit impenetrable and improbable.

Paperback:  
Using these links earns us commission at no cost to you
Review by Scotty_73
Labels:

Comments

Post a Comment

Popular posts from this blog

The Laws of Thought - Tom Griffiths *****

In giving us a history of attempts to explain our thinking abilities, Tom Griffiths demonstrates an excellent ability to pitch information just right for the informed general reader.  We begin with Aristotelian logic and the way Boole and others transformed it into a kind of arithmetic before a first introduction of computing and theories of language. Griffiths covers a surprising amount of ground - we don't just get, for instance, the obvious figures of Turing, von Neumann and Shannon, but the interaction between the computing pioneers and those concerned with trying to understand the way we think - for example in the work of Jerome Bruner, of whom I confess I'd never heard.  This would prove to be the case with a whole host of people who have made interesting contributions to the understanding of human thought processes. Sometimes their theories were contradictory - this isn't an easy field to successfully observe - but always they were interesting. But for me, at least, ...
Post a Comment
Read more

The Infinity Machine - Sebastian Mallaby ****

It's very quickly clear that Sebastian Mallaby is a huge Demis Hassabis fan - writing about the only child prodigy and teen genius ever who was also a nice, rounded personality. After a few chapters, though, things settle down (I'm reminded of Douglas Adams' description of the Hitchhiker's Guide to the Galaxy ) and we get a good, solid trip through the journey that gave us DeepMind, their AlphaGo and AlphaFold programs, the sudden explosion of competition on the AI front and thoughts on artificial general intelligence. Although Mallaby does occasionally still go into fan mode - reading this you would think that AlphaFold had successfully perfectly predicted the structure of every protein, where it is usually not sufficiently accurate for its results to have direct practical application - we get a real feel for the way this relatively unusual company was swiftly and successfully developed away from Silicon Valley. It's readable and gives an important understanding of...
Post a Comment
Read more

Nanotechnology - Rahul Rao ****

There was a time when nanotechnology was both going to transform the world and wipe us out - a similar position to our view of AI today. On the positive transformation side there was K. Eric Drexler's visions in the 1986 Engines of Creation. Arguably as much science fiction as engineering possibilities, it predicted the ability to use vast armies of assemblers to put objects together from individual atoms.  On the negative side was the vision of grey goo, out of control nanotechnology consuming all in its path as it made more and more copies of itself. In 2003, for instance, the then Prince Charles made the headlines  when newspapers reported ‘The prince has raised the spectre of the “grey goo” catastrophe in which sub-microscopic machines designed to share intelligence and replicate themselves take over and devour the planet.’ These days the expectations have been eased down a notch or two. Where nanotechnology has succeeded, it has been with the likes of atom-thick mat...
Post a Comment
Read more