Friday, August 08, 2008

The Goldilocks Enigma

Paul Davies recent book "The Goldilocks Enigma" is a fascinating exploration of why the universe seems to be "just right" for life. Interest in the fine tuning issue (which is related to the anthropic principle) has received something of a revival in recent years, primarily because of the attention paid by some physicists to the view that our universe has an improbably appropriate amount of dark energy to allow galaxies to form and hence life to evolve. In this post, I aim to evaluate possible solutions to the fine tuning problem from a panexperientialist perspective.

It should be noted that some physicists argue that the universe is as not as fine tuned for life as others would suggest, most prominent among them being Victor Stenger (papers on the subject here). This is not an area where I am qualified to judge, but Davies' comment in his book that the odds of the amount of dark energy in the universe canceling out by chance to an amount that is appropriate for life being 10 to the power of 120 to one helped convinced me that the issue is one that demands consideration.

Some critics also eschew proposed solutions to the fine tuning issue on the basis that the proposed solutions cannot be tested and hence are not scientific. Whilst I think this criticism can have relevance in relation to unscientific claims which claim to be otherwise (for example, it seems to me that aspects of string theory may be more appropriately termed mathematicised philosophy rather than science), I don't believe falsifiable, scientific explanations are the only sort of explanations that are valuable or rational. Although generally a falsifiable model is preferable to one that is not, sometimes the most that can be hoped for is inference to the best explanation.

In assessing putative inferences to the best explanation, I think two key criteria to address are those of plausibility and parsimony - explanations should be credible and no more complicated than necessary. These criteria will be used as the basis for assessing the various possible solutions to the fine tuning problem in the remainder of this post. I will also be assuming in this post that the existence of an overarching universal subject (which I have previously discussed in posts here, here and here) is a plausible form of panexperientialism.

Another preliminary point to be made is that some critics of fine tuning arguments state that as we do not know that life occurs anywhere else in the universe other than Earth, the universe may not in fact be 'just right' for life. Davies makes the point that the fine tuning argument still applies in relation to the fact that the universe permits life in at least one place in the universe. For this to occur the universe must have laws which allow stable complex structures to form, must contain the sorts of substances that life requires and must provide a setting so that substances can come together in the appropriate way. Thus , the fine tuning argument still applies even if life only occurs on Earth. A related point here is that the fine tuning argument is separate from claims regarding the evolution of life- the universe being fine tuned for life to have formed initially is entirely compatible with the subsequent evolution of life occurring through random variation and natural selection.

In his book Davies discusses various proposed solutions to the fine tuning problem - coincidence, multiverses, intelligent design by God and variations of these - and finds all of them wanting. I won't reiterate his arguments here other than to say that I agree that these explanations do not seem to rate very well on the criteria of parsimony or plausibility.

I do think the multiverse concept may have some advantages over other options if it turns out to be indirectly testable and hence scientific. Davies says that this may be the case if the multiverse theory makes the prediction that galaxy formation should be frustrated by a value of dark energy such that the universe is marginally biofriendly rather than optimally biofriendly - which would seem too 'flukey'. But one wonders that if the result did come out as too flukey that multiverse proponents might then just fall back on the argument that we just happen to be living in a universe that is even more flukey than originally supposed.

Davies also elaborates on and expresses a preference for another intriguing possible solution to the fine tuning argument derived from the work of Johnathon Wheeler. Very briefly, Davies proposes that the universe may contain a 'life principle' that constrains the universe to evolve towards life and mind. This , of course, invokes a teleological aspect to cosmic evolution. Davies introduces this teleological element without abandoning naturalistic explanation by invoking quantum theory and backwards in time causation. By extending the delayed choice experiment from the scale of photons to the scale of the universe, Davies proposes that if the entire universe could evolve until it is permeated by mind and life, then it could engineer its own creation and evolution through backwards in time calibration of its initial conditions. This has the added bonus of forming a self-explanatory loop explaining the issue of why the universe exists at all!

I must admit that this solution initially struck me as kooky as panexperientialism no doubt seems to be to many physicalists. But, on reflection, I find it an ingenious attempt to naturalisitically explain fine tuning. The main problem I would have with it is in the likelihood that non-preexisting mind could evolve to saturate the whole universe (including, presumably, the interior of stars and the vastness of empty space), which I gather is a requirement for backward causation to work on a cosmic scale. In my view, it is more plausible that mind was their to start with. Hence, I'll now propose how a panexperientialist might explain the fine tuning problem.

In constructing a panexperientialist solution to the fine tuning problem, parsimony and plausibility constraints are paramount. It would not be hard to solve the problem by imputing a cosmic subject with all the powers of a super-intelligent and omnipotent God. However, the requirement of parsimony entails that the cosmic subject should be no more complicated than necessary.

To this end, I think that the starting point for the simplicity of the cosmic subject is that the inner workings of the subject are correlated with the observed physical world. Thus, as far as possible the internal subjectivity of the cosmic subject should manifest itself to an observer as the operation of physical laws, and postulating cosmic experiences which do not have observeable physical correlates should be avoided wherever possible.

Another related application of the simplicity criterion to the cosmic subject is that the subjective dynamics of the cosmos should be correlated with its outward evolution. On this point, what can be observed from the initial conditions of the big bang to the formation of galaxies, stars and planets which permit the evolution of life is a progressive differentiation. Thus, I think the cosmic subject can be parsimoniously attributed with a drive or urge towards self differentiation (incidentally, Freya Mathews explores the idea that the cosmos realises itself through self-differentiation from a psychological perspective in her book For Love of Matter).

Whilst positing a cosmic subject with an urge towards self differentiation may get some way toward solving the fine tuning problem, it is not enough. The parameters that allowed the universe to evolve into a biofriendly state were laid down in the early stages of the big bang or shortly thereafter, whereas the conditions of the universe that allowed life to evolve (for example the differentiation from a featureless primordial gas into galaxies and stars) occurred millions or billions of years after these initial conditions were determined. Thus, even allowing for a cosmic urge towards self differentiation , how would the universe 'know' to set the parameters such that differentiation would occur far off into the future?

I can envisage two possible solutions to this dilemma. The first is the universe must be imputed with a degree of foresight such that it was aware that the setting of the parameters at the initial stages of it's evolution would allow it to differentiate further in the future. In accordance with the simplicity criterion, this ability of foresight should not be made any more complex than need be. Hence, I do not think it would necessary to ascribe any intellectual, calculative or linguistic elements to it. Rather it could be likened to instinctual anticipation on a cosmic scale. An analogy could be perhaps made with a dog knowing how high to jump to catch a ball, without knowing any of the physics involved in assessing the trajectory of the ball and the muscular forces required for the jump; and the universe knowing how to differentiate itself in it's early phases such that it's potential for further differentiation would b enhanced. Of course, the time scales between a dog catching a ball and billions of years of cosmic evolution is great, but if a subject exists on a cosmic scale then it is reasonable to assume its experience of time would be vastly different from organisms on our scale.

The other solution to the dilemma is to embrace a modified backward causation model in which the universe evolves itself through backward causation. The difference (from the previously discussed backward causation model) being that the universe already possesses an experiential character at the time of its inception, with the direction of its evolution being engineered by a more explicitly intelligent and evolved subjectivity from the future.

In terms of weighing up these two alternatives to the foresight issue, I will just say a couple of things for now. The major disadvantage which I see in positing a cosmic subject which can anticipate the future is that there are no obvious physical correlates of this anticipation. The physical correlates of a dog anticipating catching a ball could be located in the firing of its neurons, but where would the equivalent physical correlate be for the anticipative propensities of the cosmic subject? It would appear that characteristics which permit this foresight are not physically observable (or at least have not been observed to date), which goes against the parsimony constraint previously discussed .

Another factor counting against the anticipative model is that it lacks the self explanatory loop explaining the existence of the universe, which is a purported feature of the backward causation model.

However, considering parsimony from another aspect, if one is already prepared to admit the existence of a cosmic subject at the beginning of the universe on other grounds, then it is not that much more to allow this subject to possess powers of foresight. Overall, I prefer the anticipative model to the backward causation model, but this is probably just an intuitive preference more than anything else.

By way of conclusion, I think it is reasonable to say that if one accepts a panexperientialist explanation of consciousness, then a plausible and parsimonious explanation for the universe being finely tuned for life may be that this is a consequence of the drive towards differentiation of an anticipative cosmic subject. The major challenge for this model lies in explaining how the cosmic subject anticipates the future and what the physical correlates of such anticipation might be.

Conversely, I also thinks that the fine tuning problem itself adds weight to versions of panexperientialism which posit the existence of a cosmic subject.

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Steve said...

That's very interesting. I was just thinking about the fine-tuning argument also: I'm inclined to think the existence of the multi-verse disarms it, so I'm interested in Davies' analysis of that aspect. Your discussion about how panexperientialism might contribute to the solution is great and I'll have to think about that, in both the single universe and multiverse scenarios.

Justin said...

Hi Steve
I wouldn't say that Davies is a strong critic of the multiverse in the book, but he has some sympathies with those who think it is not easily testable and is an overly extravagant way to explain biofriendliness.
He notes that multiverse proponents get "sniped at" from both sides (ie by theists and other physicists).
Personally, I think there seems something fishy about multiverse reasoning - not in the multiverse per se, but in using it as anything other than a last resort explanation for improbable events.

Steve said...

Right. From a scientist's perspective, if it isn't testable, that's a problem. From a philosopher's perspective I think it is fair game, as long as there isn't a more parsimonious explanation which does the same work.

Justin said...

Yes. I'm just not sure it is a very parsimonious route. But I think as scientific support for the multiverse explanation increases (if it does)then it will become a more preferred option.

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H.C said...

The multiverse concept violates Occam's razor in the most gross way in my opinion. We would need to postulate a multitude of worlds that we cannot see. Compared to that, the invisible pink unicorn is child's play.

My bet is on a pre-physical stage that existed at the moment of the big bang - a period when the rules of physics themselves were settled by some kind of emergent process.

What puzzles me the most is why is the universe causally consistent? Why dropping a rock, any rock, on any planet, would follow the same law of gravity? This consistency makes me believe there must be a pre-physical layer from which consistency and homogeneity is supported into this physical world. And this pre-physical layer is the laboratory where the universe was probably "fine tuned".

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