Science Denial & the Fine-Tuning of the Universe for Life
Last week I caused bit of a Twitter storm by accusing those who deny that the universe is fine-tuned for life of science denial. Maybe that was a bit over the top. Still, a huge number of high-profile scientists accept that, according to our current theories, the universe is fine-tuned for life: Barrow, Carr, Carter, Davies, Dawkins, Deutsch, Ellis, Greene, Guth, Harrison, Hawking, Linde, Page, Penrose, Polkinghorne, Rees, Sandage, Smolin, Susskind, Tegmark, Tipler, Vilenkin, Weinberg, Wheeler, and Wilczek, to name but a few (list taken from this review paper). It’s certainly a mainstream position, arguably the generally accepted position. If a physicist wants to make a careful, informed argument that the universe isn’t fine-tuned for life, then that’s fair enough; and not being a physicist myself, I’m probably not going to be able to put up much of a defence. What I was objecting to, and what I see all the time, is people declaring there’s ‘no evidence’ that the universe is fine-tuned for life, without pointing to any scientific work to support this claim.
Probably part of the response was misunderstanding what ‘fine-tuned for life’ means. In the standard terminology used in both physics and philosophical discussions of this topic, to say the universe is ‘fine-tuned for life’ does not imply there was a literal fine-tuner. It is simply the claim that, for life to be possible, certain of the fundamental constants of physics had to have values falling in a certain narrow range. This is perfectly compatible with any of the following positions:
The fine-tuning of the universe is explained in terms of a multiverse.
Although the universe is fine-tuned for life, we cannot say that a life-sustaining universe is improbable, as we can’t make sense of the kinds of probabilities expressed by such a claim.
According to our current theories, the universe is fine-tuned for life, but those theories will change.
I disagree with all of these responses to fine-tuning (see my recent book Why? for my objections), but they are certainly respectable positions that need to be dealt with seriously. What is not respectable is to dismiss a mainstream scientific position for ideological reasons. This happens with respect to the science of climate change, and it is also common to see with respect to the science of fine-tuning.
Photo by Mingwei Lim on Unsplash
the claim: "for life to be possible, certain of the fundamental constants of physics had to have values falling in a certain narrow range."
what is the empirical motivation for the phrasing of values "falling in a certain narrow range"? do you have any evidence to motivate that values 'fall' into a range from some other, different range, or that there was a prior state of undetermined potential from which certain values spring forth from potentiality into actuality? do you have any empirical evidence that said values are contingent?
if not, i just don't grasp what motivates creating the explanandum, but my credence is high that it's not some idyllic, neutral following "the" evidence wherever it leads.
Perhaps the universe is fine tuned by being based on a four dimensional manifold with one dimension of an opposite sign. Symmetries within this form are the physical conservation laws (Noether). Quantum physics falls out of de Broglie's original analysis. We would expect that such a geometrical form would host conscious observers which is why it is the universe we inhabit.
Of course this gets sticky if we move beyond Special Relativity but its an approximation.