Tag Archives: Cosmology

God Probabilities Are Pointless, Even From Physicists

Physicist Sean Carroll indulges one of his physics colleagues in a post Guest Post: Don Page on God and Cosmology. Sean:

Don Page is one of the world’s leading experts on theoretical gravitational physics and cosmology, as well as a previous guest-blogger around these parts. … He is also, somewhat unusually among cosmologists, an Evangelical Christian, and interested in the relationship between cosmology and religious belief.

From here on I’ll address Don on his piece, by picking up only the statements I think are really problematic. I’m basically repeating what I wrote in the comments section, with some minor mods. Continue reading God Probabilities Are Pointless, Even From Physicists

The Rescue of Philosophy of/in Science

[This is part of a set: Thinking]

I obviously don’t mix in the right internet circles. For some time I’ve been seriously disappointed by what I’ve seen of modern philosophy. It’s so exasperating, and I’ve come across so many examples, that I’ve not had chance to blog about them – while I’m contemplating one, up pops another to get my goat, and in the end they pass me by.

I’ve managed to make some points, here: Plantinga, Law, Coyne: Theology, Philosophy, Science, here: Philosopher Stephen Law Doesn’t Get Science, here: Thought v Experience.

But there are plenty more examples out there, of how philosophy isn’t keeping up with science in the interesting stuff of metaphysics. It’s too much to expect of any fallible human, which accounts for all humans, that those of us who are philosophers should be perfect thinkers, just because thinking is their speciality. So we do have to cut them some slack.

Well, it’s not all bad. This piece, What Happened Before the Big Bang? The New Philosophy of Cosmology, tells us how philosophers are doing their bit. It starts with this, which carries the sentiments of may scientists:

Last May, Stephen Hawking gave a talk at Google’s Zeitgeist Conference in which he declared philosophy to be dead. In his book The Grand Design, Hawking went even further. “How can we understand the world in which we find ourselves? How does the universe behave? What is the nature of reality? Where did all this come from? Traditionally these were questions for philosophy, but philosophy is dead,” Hawking wrote. “Philosophy has not kept up with modern developments in science, particularly physics.” [my emphasis]

Ross Andersen tells us about groups of philosophers in the US and UK who are staking a claim for philosophy, which is good news. There’s a real place for philosophy in both pushing the boundaries of thought, in going where science is yet unable to, and for scrutinizing science itself, and scientists that do science, to make sure their critical thinking skills are on the ball.

Ross talks to Tim Maudlin, at NYU, who puts Hawkins in his place.

Tim doesn’t reveal anything here that I’ve not already heard from scientists. Some scientists are pretty good at the philosophy associated with their subject. Lawrence Krauss, Peter Atkins, Sean Carroll, Neil deGrasse Tyson, …, there are a ton of popular scientists who tell it like it is, or how it seems it might be, without wondering off into the realms of fancy that many philosophers tend to do.

But the project seems like a good idea, so I’ll have to dig deeper and keep an eye on them.

Here’s one bit where, for me, Tim gets it dead right:

Now, one can first be a little puzzled by what you mean by “how likely” or “probable” something like that is. You can ask how likely it is that I’ll roll double sixes when I throw dice, but we understand the way you get a handle on the use of probabilities in that instance. It’s not as clear how you even make judgments like that about the likelihood of the various constants of nature (an so on) that are usually referred to in the fine tuning argument.

This is a point I’ve tried to make to a few fine tuning enthusiasts. We don’t have the first clue as to what’s required in the universe manufacturing process. We don’t know a damn about the probabilities involved.

And this:

Now let me say one more thing about fine tuning. I talk to physicists a lot, and none of the physicists I talk to want to rely on the fine tuning argument to argue for a cosmology that has lots of bubble universes, or lots of worlds. What they want to argue is that this arises naturally from an analysis of the fundamental physics, that the fundamental physics, quite apart from any cosmological considerations, will give you a mechanism by which these worlds will be produced, and a mechanism by which different worlds will have different constants, or different laws, and so on. If that’s true, then if there are enough of these worlds, it will be likely that some of them have the right combination of constants to permit life. But their arguments tend not to be “we have to believe in these many worlds to solve the fine tuning problem,” they tend to be “these many worlds are generated by physics we have other reasons for believing in.”

“I talk to physicists a lot” – Wow! This is what we want to hear. That can’t be said of many philosophers, and even less for many theologians.

Tim finish with this:

I will make one comment about these kinds of arguments which seems to me to somehow have eluded everyone. When people make these probabilistic equations, like the Drake Equation, which you’re familiar with — they introduce variables for the frequency of earth-like planets, for the evolution of life on those planets, and so on. The question remains as to how often, after life evolves, you’ll have intelligent life capable of making technology. What people haven’t seemed to notice is that on earth, of all the billions of species that have evolved, only one has developed intelligence to the level of producing technology. Which means that kind of intelligence is really not very useful. It’s not actually, in the general case, of much evolutionary value. We tend to think, because we love to think of ourselves, human beings, as the top of the evolutionary ladder, that the intelligence we have, that makes us human beings, is the thing that all of evolution is striving toward. But what we know is that that’s not true. Obviously it doesn’t matter that much if you’re a beetle, that you be really smart. If it were, evolution would have produced much more intelligent beetles. We have no empirical data to suggest that there’s a high probability that evolution on another planet would lead to technological intelligence. There is just too much we don’t know.

Yes! A philosopher gets the insignificance of human intelligence on both evolutionary and cosmological scales! This is so promising.

Still, I can’t let him get off with a free pass. There’s the minor quibble that maybe, once intelligence emerges, that either there’s only really room for one intelligent species, because they wipe out the others (along with all the non-intelligent species they wipe out too); or, that there’s just one remaining intelligent species on this planet is down to just plain evolutionary bad luck – the others happened not to be fit for survival at the time they arose.

There’s the distinct possibility that, given enough evolutionary time, other species could evolve to become intelligent examples. Given that we are here, that doesn’t seem likely at the moment. But an asteroid, or human action, could cause the extinction of human and much mammalian life on this planet. Then, left to its own devices, who’s to say earth wouldn’t see the rise of intelligence again, from a completely different branch of the tree of life. We can speculate, philosophically, but we don’t have the data to be sure of or to rule out these very plausible outcomes.

As I said, I minor quibble. I’m looking forward to finding out more about these philosophers.

Re-running The Universe: Determinism, Indeterminism, Quantum Stuff

[This is part of a set: Thinking]

The philosophical persuasiveness or either determinism or indeterminism has been made foggy by the success of quantum physics, in particular the apparent indeterminate nature of the world, that is the result of quantum physics.

One question that arises is the extent to which we can be sure, or not, that the universe is deterministic. Does ontological determinism hold?

[This follows from another post which assumed determinism for the points made. It ignored quantum stuff.]

From the point of view of a scientist there is the laudable position that we go wherever the evidence leads – and I agree with that. It appears that all the science is telling us that we live in a quantum indeterministic world, but with determinism at the macro level that allows us to make limited predictions.

So, if anyone wants to argue on the basis of evidence, then that’s it. The world is a deterministic+indeterministic mix. But it is indeterminate anyway, epistemologically, to those entities within it.

At our macro level we can still argue that there is a determinism that appears as a result of any quantum event, once it has occurred. Once a particle has had a causal effect on another, to a measurable degree, then the outcome is, within limits, deterministic.

One question that often arises is this. If we ran the universe again, would all the same events occur? The quantum non-determinist would say that, no, it would not, because quantum events are by nature indeterminate and would result in a different outcome.

But, given that we can’t re-run the universe this is a speculative position. Here I give several alternatives that I see. What follows assumes there is some sort of existence of something outside our universe – that our universe is contained in some way, so that the starting conditions can be set up the same way, down to whatever detail one might like to speculate about.

Determinism seems to require causality, otherwise what does it mean for one state to be determined by prior states. On the other hand, if there is a genuine time symmetry, then effects would cause causes, when considering time reversal. A one-way time dimension can also be causal the one way (which is what we perceive), and yet even in this universe Galilean physics is time reversible. Anyway, putting time issues to one side for now, here we go:

1) Indeterminate Universe. In this case there might or might not be causal relationships. It might be the case that there is no causality, just correlation – weak observed correlation. How does a completely indeterminate universe allow for predictability? Maybe it doesn’t. Maybe what we perceive as repeatable predictable outcomes – say from y = mx + c – are just coincidental correlations. If the universe is so indeterminate in actuality, in practice it’s difficult for us to figure that out, to ‘determine’ its indeterminism, as it were. This is somewhat like the reality-solipsism dilemma – we can’t tell the difference. The point though, in the context of this post, is that to re-run this universe with the same starting conditions will result in a different universe each time.

2) Deterministic Universe. In such a universe every event is determined causally by prior events. This is a point of view that might have been held prior to our discovery of the quantum indeterministic nature of the universe. In such a universe it would re-run exactly as it did on a previous run. On the face of it, at the macro level, it seems a reasonable working hypothesis. We observe what we think are deterministic connections on many levels of science, and other than quantum indeterminacy, we’ve observed no evidence against determinism.

3) Quantum Indeterminate Universe. In such a universe, even with identical starting conditions, the re-run would produce a different universe, because of the truly indeterministic nature of quantum events. This seems to be how some scientists view the consequences of quantum physics in our particular universe. But this seems to require some knowledge of facts outside our scope. Consider, if the quantum indeterminacy is, at some other level, actually determinate, but our understanding of physics is mistaken, then how would we tell the difference? Only a re-run of this universe would reveal the true quantum indeterminacy because a different universe would appear on each run.

4) Quantum Determinate Universe. In this universe even the quantum events are determined – though I refuse to speculate on how that might occur. Note though, that to the entities contained within each ‘run’ of that universe the quantum events would still be non-deterministic, because those entities are contained within the re-running universe and are bound by the evolving quantum events that are taking place. So, on each re-run, the inhabitants of the universe are convinced that their universe is non-determinate because of the observed quantum events, and yet on each re-run the very same quantum events are occurring, deterministically, and each re-run produces an identical universe.

Now, (4) is purely speculative of course. But then so are all of these options, because we don’t have a view of our universe from the outside and over re-runs of it. So, I don’t see any justification for being dogmatically committed to any of these views.

Perhaps the important point is that we do not know what our science is telling us about the deep status of our universe. It is all metaphysical speculation. And, I repeat an earlier point, to us it’s all indeterminate anyway. We cannot tell the difference between a determinate and an indeterminate universe if we ar a part of it.