AC WP RSCN4338 ENH2Recently I encountered the little book, Agnosticism – A Short Introduction , by Robin Le Poidevin, one of many new ‘short introduction’ editions produced by Oxford University Press, books so small and slim that they will fit in any pocket, yet they’re well-written, interesting and informative.

Le Poidevin demonstrates that often only the agnostic stands on firm ground, because only he or she knows when they don’t know.

This isn’t confined to religion. One can be agnostic about anything. For example, the Big Bang.

Most scientists, and science writers, today refer to the Big Bang as if it is a certainty that the universe began in some kind of explosion or eruption 13.7 billion years ago and has been expanding ever since.

The astronomer Edwin Hubble, the so-called ‘discoverer of the Big Bang’, with his assistant Milton Humason proved that galaxies were collections of stars. Soon after, they also confirmed that almost all galaxies have a red shift in their light.

Almost immediately, it was proposed that this red shift must be some kind of Doppler effect, that is,  the light waves were being ‘stretched’ by the expansion of space. This was considered proof that the universe is expanding. It didn’t take long for that to be converted to a creation story – the Big Bang.

While the rest of the world celebrated this apparent wedding between science and religion, making up for their longtime differences, Hubble warned that we did not know what was causing the red shift of galactic light. He considered it a mistake to assume that only the expansion of space could cause the red shift. For example, in a speech in 1936 he said:

The explorations of space end on a note of uncertainty. And necessarily so. ….. We know our immediate neighborhood rather intimately. With increasing distance, our knowledge fades and fades rapidly. Eventually, we reach the dim boundary – the utmost limits of our telescopes. There we measure shadows, and we search among ghostly errors of measurement for landmarks that are scarcely more substantial. ……The search will continue. Not until the empirical resources are exhausted, need we pass on to the dreamy realms of speculation.

That is the statement of an agnostic. Though he said it decades ago, it still fits with what we know and don’t know today.

Until his death in 1953, Hubble continued to believe that we were “measuring shadows” and should refrain from drawing conclusions.

But over the years, others have supported him. His physicist friends, Fred Hoyle and Geoffrey Burbidge were always behind him, Burbidge still insisting on this position until his death in 2010. Even physicist Richard Feynman, who won a Nobel prize for his work in quantum physics, said he could never understand why the effect of gravity over the great distances that galactic light had to travel wasn’t being considered.

Carl Sagan, in his book Cosmos, which accompanied the TV series of the same name, said that if galaxies were found to have black holes at the center of them, we should consider whether their gravitational fields might be causing, or contributing to, the redshifts of galaxies. Of course, we now know that there are giant black holes in the center of most, and maybe all galaxies, but no one seems to be discussing that in the context of the Big Bang.

More recently, many younger astronomers and physicists have begun to question the reality of the Big Bang (see my post re the letter to New Scientist by 33 of them). The recognition that the evidence for a ‘Big Bang’ is weak seems to be growing.

Pretending that you know something when you don’t really know it became fashionable a long time ago. It’s not just in the Big Bang dispute. You see it everywhere now, everyone convinced that they know. It’s time for agnosticism to make a comeback.

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