The discussion was supposed to cover all the issues raised in the book, but got bogged down on the issue of the 'fine tuning' of the universe. While Croft did a remarkably good job of shooting down Glass's fine tuning argument and discrediting his flawed use of probabilistic reasoning, he never managed to convince Glass that his take on the fine tuning argument was anything less than water-tight.
The fine tuning argument is summarised in this way on Wikipedia:
"The fine-tuned Universe is the proposition that the conditions that allow life in the Universe can only occur when certain universal fundamental physical constants lie within a very narrow range, so that if any of several fundamental constants were only slightly different, the Universe would be unlikely to be conducive to the establishment and development of matter, astronomical structures, elemental diversity, or life as it is presently understood. The existence and extent of fine-tuning in the Universe is a matter of dispute in the scientific community."The point is that certain universal constants are built-in to the universe, and without these constants the universe could not sustain life (or, at least, life as we know it), yet there is (so it is claimed) no scientific explanation for why the constants should have those values, and not other values, which would have resulted in a universe incapable of producing life.
The main theistic argument here goes like this: the probability that the constants could have just happened upon the 'correct' values 'by chance' is so vanishingly small that it didn't happen. Those constants must have been selected by an intelligent designer, so therefore there must be a God.
Atheistic counter arguments usually go two ways:
The first is to propose a multiverse type arrangement where there are an infinite number of possible universes, each with a different set of universal constants. These universes may either be in series in infinite time, or in parallel in infinite dimensions. Given enough coordinates in probability space, then it becomes highly likely that somewhere in all this probability there will be a universe with the 'correct' set of universal constants. This way of thinking is favoured by a great many scientists. Of course, this raises the issue of the unseen infinite which I have blogged about before - you can demonstrate that anything can be achieved if you can invoke the explanatory power of an unseen but infinite factor.
The other way is to show that the issue is being looked at the wrong way around. It is not that the universe was fine tuned for our kind of life to emerge, but rather that our kind of life is a product of the kind of universe in which we are. Universes with different sets of constants, should any exist, would produce different emergent types of life, but in every instance it would appear (to the emergent life) that the universe was fine tuned for them to exist.
The show set me considering whether the theist actually has a valid argument. I actually found myself wondering this way:
Suppose the universe was created by a supernatural being who preset the fundamental constants, how did that being decide what the constants should be? Did he (lets stick to convention here and refer to the deity as masculine) try out any other sets of constants in other universes only to discover that they didn't work? How many times did he do this? Even if he only did a 'thought experiment', this is still working through all the possible alternatives until a solution is found. Following this line of reasoning you very quickly end up with the multiverse type arrangement (again with the inherent unseen infinite problem) and God is reduced to the mere mechanism by which the various universes choose their parameters.
Of course, no theist really thinks like this. It is obvious to them that God would just know what the 'correct' parameters should be. But why? For the theist it is not that God had to work out the right parameters, he just knows them. I suppose you could say that the correct parameters for the universe are just there in the mind of God. But how is this thinking any different from the non-theist explanation which thinks that the correct parameters are just built in to the universe and couldn't be otherwise?
In order to demonstrate that the parameters are 'fine tuned' you actually need to be able to demonstrate that the parameters could have been otherwise. As far as I know, no theist has ever done this. As far as we can tell, those parameters are necessary features of our universe and not variables.
Fundamentally, the fine tuning argument for God does not and cannot explain how God came up with the set of fundamental constants that appear to be built into our universe. In other words, it has no explanatory power.
It boils down, basically, to these two options:
- The universe has a set of physical constants built into it at the outset. We do not know how these constants were fixed. Or
- The universe has a set of physical constants built into it at the outset. They were put there by God. We do not know how these constants were fixed in the mind of God. We do not know how God came to be there.
Should we use Occam's razor here?
3 comments:
The issue is whether a set of constants enables the formation of informationally complex structures. There is a unique criterion: the organized particles must be capable of Turing-universal computation. One reads that many parameter settings preclude the formation of sufficiently rich structures. Your point of alternative life forms is accounted for, and there are people who hold that the range of possible alternatives is underestimated. (Here is a reference to Stephen Baxter, which rings the bell I had in mind.)
My angle is the idea of an attribute, human or otherwise, that cannot be excelled. There is lots about the design of life as we know it that could be bettered---Neil DeGrasse has a noted quip to that effect---so none of those aspects is such an attribute. The only two I've been able to think of are the capacity for love and the capacity for Turing-universal computation; the Church-Turing thesis asserts that the latter cannot be excelled in any physical regime. (I was an onlooker for David Deutsch's challenge to that in Oxford in 1985, which was turned aside.)
So to try to answer your interesting point about choice among life-supporting constants and query about what could be "in the mind of God", I can point only to such attributes above all else, the rest being ancillary.
You say, "In order to demonstrate that the parameters are 'fine tuned' you actually need to be able to demonstrate that the parameters could have been otherwise. As far as I know, no theist has ever done this." Isn't the whole point of the anthropic question, whether or not one is a theist, that the constants could have been different? As I understand it, the reason certain values are considered "fine tuned" is exactly because there is no known reason why they should be what they are. Of course, a reason could be forthcoming, but currently they appear arbitrary.
An infinite multiverse could solve the problem, but with the weaknesses you point out. I don't understand your objection to God planning the universe the way it is. Rather than conceptualizing God as "trying out" a vast assortment of constants, as if he were an experimenter, isn't it possible that he simply "spoke" the universe into existence as he wanted it to be? The observed physical interactions would be a result, not a constraint, of what he wanted to perform.
The fine tuning argument does presuppose that the constants could have been otherwise, but I have never heard this demonstrated. It is just speculation. And without that speculation the fine tuning argument falls apart.
Yes, I suppose the Christian view is that God simply 'spoke' the universe into existence in the way he wanted it to be, but my question goes one step back from that - how did he know that the thing he spoke would work? Did he try others first (either as real or thought experiments) and they failed? The theist says no, God simply knew the right constants. That is, the right constants were simply there in the mind of God. This is pretty much analagous to the way in which the constants appear to be simply there in the nature of the universe. So why do we need God as an explanation here? The constants are just there in either case, but one theory also needs an additional infinite God.
Post a Comment