Thursday, October 07, 2010

Michael Turner's Review of "The Grand Design".

Ultimately, for me at least, I must prefer someone who understands the physics of what is being discussed to make an INFORMED review of a physics book, even if it is a pop-sci book. All the brouhaha surrounding Hawking/Mlodinow's book has been generated by people who could barely understand basic physics.

So it was with great interest that I read Michael Turner's review of this book in this week's Nature (Nature, v.467, p.657 (2010)). And as I suspected, he has a very interesting take on this that many non-physicists have missed.

Despite publicity to the contrary, The Grand Design does not disprove the existence of God. Science has not had much new to say about God since mathematician Pierre-Simon Laplace remarked to Napoleon that he had no need for “that hypothesis” when asked why he had neglected the deity in his treatise Mécanique céleste (Celestial Mechanics, 1799–1825). Rather, theoretical physicists Stephen Hawking and Leonard Mlodinow offer a brief but thrilling account of some of the boldest ideas in physics — including M-theory and the multiverse — and what these have to say about our existence and the nature of the Universe.
Thus, say Hawking and Mlodinow, there is no miracle — inflation plus M-theory equals multiverse. Our special Universe is a selection effect: all possibilities have been tried and we find ourselves in the only kind of inflationary patch that can support our existence. The grand design is unnecessary. One is reminded of Winston Churchill damning the United States with faint praise — they get it right after they have exhausted all the alternatives.

The multiverse is possibly the most important idea of our time, and may even be right, but it gives me a headache. Is it science if we cannot test it? The different patches are incommunicado, so we will never be able to observe them. The multiverse displaces rather than answers the question about choice and who chooses, and does not explain why there is something rather than nothing. Hawking and Mlodinow argue that negative gravitational potential energies allow something to arise from nothing — but that still begs the question of why there is space, time and M-theory at all.

Hawking has not ruled out the existence of God, or even the odd possibility that our creator is a physics student in an advanced civilization carrying out a routine lab experiment. He has strengthened Laplace's argument that, although some assembly process is required, no creator is necessary. It is well known that Hawking is no fan of religion, but it was the media who took “no necessity for God” to mean “no God”.
Yet The Grand Design reminds me, as I tell my students, that science doesn't do 'why' — it does 'how'. Physicist Richard Feynman discussed the dangers of 'doing why' in his 1964 Messenger Lectures. He warned that should we achieve the Ionian goal of finding all the laws, then “the philosophers who are always on the outside making stupid remarks will be able to close in”, trying to explain why those laws hold; and we won't be able “to push them away” by asking for testable predictions of those ideas. Time will tell if we are on to something big with the multiverse, or if we are becoming the philosophers that Feynman warned about.

There ya go! Isn't this similar to what I mentioned earlier?



Dhulqarnain said...

"Yet The Grand Design reminds me, as I tell my students, that science doesn't do 'why' — it does 'how'."

This is a very problematic statement. To what extent does the 'how' answer the 'why'? Is this a reflection of the limitations of science, or of our own conceit? Specifically, I think there are two levels at work here. They are artificial and surely only due to our own preconceived notions going in.

Consider, for instance, the question why plants are green. We can go, and in fact have gone, deep into the biology, chemistry and physics to figure out the necessary answer. It is a satisfactory answer. It certainly answers the 'why'. Nobody seeks an existential reason for the 'why', unless it is to ask what permits the laws of physics to be just so.

But it seems to me people seek a deeper meaning than needs to be assigned to certain things. Things dealing with the 'why' of life or of the cosmos. They go in with an idea that there must be something deeply significant for why life exists, and why the Universe exists. In general, this significance typically takes the perspective that the powers that exist in the Universe do so for our benefit, rather than their own. As such, they believe the 'whys' have to be referenced to the human condition. This is absurd.

Consequently, when science (eventually) answers the 'why', like in the why-are-plants-green question, it is interpreted as only answering the 'how'.

As you can probably tell, I'm convinced science answers the 'why' question; it is we who load the problem with our own intellectual/emotional baggage.

S.D said...

It tends to confuse an immature young science student or a general audience when a veteran says 'science does not why but how'. This saying is frequently used to warn those who devolved in non-scientific questions (not concerned with nature). It would seem very obscure if the context were not considered. Because scientists ask not only 'how' but also 'why', and these two often turn out the same in essence. It may be better to avoid using such seemingly deep but vague statement.