Christianity Index Science Index Philosophy Index History Index
Books Index Table of Contents Discussion Forum Blog


If you have enjoyed Bede's Library, you can order my book, The Genesis of Science: How the Christian Middle Ages Launched the Scientific Revolution (US) from or God's Philosophers: How the Medieval World Laid the Foundations of Modern Science (UK) from

For my latest thoughts on science, politics, religion and history, read Quodlibeta




Is it reasonable to believe in a god?

Bede's negative construction

In this debate, I will not be trying to prove the existence of God, as it is common ground that this is, for the present, impossible. Instead, I will try to show that the hypothesis that a deity (by which I mean a creator of the universe) exists is one that can be held by a reasonable man. Of course, there is no question that many reasonable men, such as the esteemed scientists Professor Kenneth Miller and Sir John Polkinghorne, do hold to just such a hypothesis.

A deity is a reasonable hypothesis because it has a high explanatory value and is consistent with the evidence available. Unfortunately, this evidence is either not direct - no one has seen a deity for quite a while - or too subjective to be convincing to a third party. Ultimately, to really believe in the God that I worship, it is necessary to experience Him first hand and no amount of philosophical argument can change that. Consequently I will not be touching on what a deity might be like, whether it is nice or nasty or even if it can be experienced by humans at all. In short, I will be arguing from the position that Cygnus used to occupy - that of a deist.

I will take for my evidence the facts of science that one can find in textbooks devoted to the subject. A scientific fact is not a philosophical certainty but it is something accepted by the community of mainstream scientists and forms part of what Thomas Kuhn famously called a paradigm. For this reason the mind stretching cosmological theories of Stephen Hawking, Alan Guth and others will not be on the table. Superstrings, for example, are an exciting area of research but they could very well end up in the same dustbin of history wherein we can already find phlogiston and aether (imaginary substances that formed the basis of eighteenth century chemistry and nineteenth century physics respectively). There is no direct evidence for superstrings even though they have a high explanatory value and are consistent with the evidence available.

Delving into physics textbooks we find that general relativity coupled with conclusive experiment tells us that the universe began fifteen billion years ago and that space and time were both formed together in that explosion. We further learn (confirmation of this being only recently published) that the universe will continue to expand forever at an ever slowing rate. This means there will be no big crunch and there is no cosmic concertina effect. Finally, we can see that the laws of physics depend on a number of constants that cannot change by very much without making the universe completely unable to support life-as-we-know-it. This is usually called the anthropic principle or 'fine-tuning'. Not all of the above is accepted by every working scientist but most is believed by most of them. The reasonable man can, therefore, subscribe to it all without in any way compromising himself.

A hundred years ago it was the atheist position that the universe was eternal and had no beginning. We find this in the writings of Russell, Teller and others. I have always felt this to be a very reasonable position as I can see no prior reason why the universe must have a beginning - scripture and the Kalam cosmological argument not withstanding. However, science has shown these atheists to be wrong and as the universe does have a beginning I feel it is equally reasonable that it must have a cause and that the cause itself must be eternal. This position is identical to that of Russell, a self confessed exemplar of reason, except the eternal, by necessity, retreats one step back.

Furthermore, as the universe is contingent and finely tuned, it does not seem at all unreasonable to ask why it is that it has the properties that it does and postulate a creator. While answering this question may itself lead to further questions, that is an attribute of nearly every causal explanation we ever suggest.

The arguments against fine tuning by an eternal creator usually fall along these lines:

a) Is not our universe all that can exist?

The fine tuning argument requires us to postulate both that the universe could have been different and that it had an outside cause. This requires that our universe is not all there is.

It is certain that our universe is the only one of which we have any knowledge but we cannot from this reasonably postulate that it is therefore all there is without at least some further evidence. Aristotle did insist that only our world existed and this was part of his worldview that Christianity successfully overthrew in the march towards modern science. For the atheist to claim that nothing else is possible, he needs to be backed up with rather more than the observation that there is nothing else he can see.

A more philosophically minded individual might claim that the fact we cannot know anything about outside the universes (with which I would agree from a scientific point of view) is tantamount to saying it does not exist. But this is a mistake. Firstly, it draws a bright line between knowable and unknowable that no one should countenance and secondly it assumes there is no difference between the proposition that nothing outside the universe is possible and that something is. The fact that we are even having this debate refutes the latter point. Regarding the former, it would be bold enough to take the view that only what actually exists can possibly be without going further out on a limb to proclaim that only what is known to exist can exist.

b) Is the universe not a just a brute fact?

Related to all this is the brute fact hypothesis. At heart it is the same as Carl Sagan's statement of faith at the start of his book Cosmos that the universe is all there is and all there ever will be. To look beyond it for explanations is pointless because it has no cause and came from nowhere. The Big Bang was creation ex nihilo without even a creator. My response would be that I will ask the question and like any good scientist I will assume there is an answer. Any other attitude would send us back to the stone age although I wonder why atheists seem to apply the brute fact argument to theists but not cosmologists.

c) Must not all universes be like ours?

Unlike the one above, this question admits that while other universes are possible they might, in fact, all have to have identical laws of physics to this one.

In his dreadful book Creation Revisited, Oxford chemist, Peter Atkins, suggests that the laws of nature might be reducible to logical principles that must hold true. In other words, any universe must have the laws of physics that ours does. Leaving aside that it is impossible to even reduce mathematics to a set of logical rules, Atkins would need to derive every physical constant and rule from, as he puts it, elegantly reorganised nothing. I am not the only one to consider this pie in the sky.

d) Is the universe really so finely tuned?

We cannot know that our particular set of physical laws and constants are the only ones that will produce a viable universe. There may be others and other possible universes. What we can say, however, is that the number of viable universes compared to the number of dead and desolate ones is probably infinitesimally small. Most thinkers recognise this and call the various factors that are just right for us to exist the anthropic coincidences. So although these coincidences represent a highly unlikely set of circumstances we do not need to claim that ours is the ONLY possible life supporting universe.

Another point put forward by the atheist is that we cannot imagine what strange life forms could exist in alien universes and hence we cannot make any judgement on whether or not they are likely. This is simply an appeal to ignorance (something theists are often accused of) and one can respond to it by saying that the fine tuning argument is valid according to the current state of scientific knowledge. We are all happy to modify our position if more information becomes available. After all, that is the only way to reach conclusions from the evidence.

e) Could there not be multiple universes and we just happen to be in the right one?

A popular alternative to a creator is the multiple universes hypothesis. It states that there could be zillions of universes, each with slightly different properties, and we just ended up with one in which we can live. After all, says the atheist, smiling disarmingly, if the universe were otherwise we would not be here to see it.

The problems with the multiple universe theory are manifold but the most important is that we have no evidence for them whatsoever. They are not necessary as a consequence of any other physical theory and there is no theory that predicts they might exist. For the multiple universe theory to help the atheist at all, the universes must all have different physical laws and no one has any idea why this might be. Although we cannot show any reason why our universe should have the physical laws that it does, we also have no mechanism as to how they could be any different either. This comes into play when one wants to postulate multiple universes with differing physical laws so that there is scope for one of them to be just right for us. There is a distinction between asking why our universe has the properties it does while not accepting that it had to be this way and asking how the postulated multiple universes all came to have the variations of those laws so that they can be an explanation for fine tuning.

Furthermore, the vast number of universes required seems to insult every principal of scientific elegance from Ockham's razor onwards. The atheist should realise that hypothesising multiple universe is metaphysics and not science. It is not a scientific theory because it cannot be experimentally verified or falsified and neither can it be considered superior just because it is naturalistic. Once we move into metaphysics the naturalistic assumption of science must be done away with as it is no longer either justifiable or useful. Indeed it is a metaphysical statement itself as it lies behind science but cannot be examined scientifically.

In summary the three schools of thought about the reason the universe is as it is are Chance, Necessity and Purpose. Chance, to be vaguely plausible requires a near infinite array of universes in order for there to be a fighting chance that a few will support life. We have no evidence for these universes, no theory that suggests them and no reason to hypothesise them except to support this theory. They must, therefore, be rejected. Necessity is the idea that the laws of basic logic will ensure that our universe is the only possible one. The trouble is that basic logic cannot even provide a strong enough foundation for mathematics, let alone the laws of physics. There is too much that is simply arbitrary and cannot be reduced to any intuitively obvious laws.

This leaves us with Purpose. We have already established that it is reasonable to hold that the cause of the universe is eternal. This means that a creator deity must be a reasonable hypothesis. I am not claiming proof but simply stating that a reasonable person could believe this was the best available explanation. It was the reason I ceased to be an atheist at college although it was many more years before I actually became a Christian.

Next page of debate

Contact me

James Hannam 2001.
Last revised: 08 December, 2009 .