Thursday, March 20, 2014

The First Mover

Yesterday, I watched a debate on God in this series of YouTube videos. I was thinking I would comment on some of the arguments.

The unmoved mover argument for God goes something like this. Nothing moves without first being moved by something else. However, there is motion, so there must also be an unmoved mover. That mover is God.

I think this argument gets you somewhere, but not quite to God. 

One argument against it is that there is no beginning to motion. Motion just goes on infinitely backwards. Possible, although evidence for the big bang undermines this argument.

Another counter-argument is that, while there is a first mover, that mover is not God. There is simply some other cause of motion. The rejoinder is that the unmoved mover is by definition God, regardless of what you call it. 

But I don't think that saying the unmoved mover is, by definition, God is quite right. Sure, we can call the unmoved mover God, but that's not really the God that we're trying to prove-- a God that takes some interest in our lives. Proving that there is a thing or phenomenon that causes motion without being moved itself does not prove that that thing cares about us humans.

But I do think the existence of motion creates some problems for atheists. Assuming motion does not go back infinitely as the big bang suggests, science currently cannot explain motion. God's existence, however, can explain motion.

Atheists might argue there is a non-god unmoved mover, we just don't know what it is. But without some evidence, this is just a declaration of the atheist's faith. Believing in a non-god explanation for motion is no more based on evidence and reason than believing in God.


Ryan said...

Admittedly, the arguments for and against God do not exist in isolation. An atheist could argue that he finds some other argument against the existence of God definitive, and from the premise of no god concludes there must be an explanation of motion that doesn't involve God.

Still, I think the atheist is exercising faith by believing there is a scientific explanation for motion, even though the existing laws of physics cannot explain it.

Brett said...

I'm curious if someone has articulated an updated unmoved mover argument. It seems to me that modern cosmology would recast the question a bit.

For one, while it's still quite controversial, the scientific community is warming to a multiverse cosmology which would move the first mover question beyond the Big Bang. But whether it's a scientific or religious question, I don't see an escape from infinite regress. If the multiverse gave birth to our universe, where did the multiverse come from? If God started all movement, how did God get there?

Cosmology also addresses the question of motion from no motion. As far a momentum is concerned, you can start with zero momentum and then create momentum as long as there are equal amounts in opposite directions (since it is a vector quantity the sum is still zero). Energy is more tricky. Kinetic energy is always positive, so if you push on something and it goes forward while you go backward, you both gained positive kinetic energy which had to come from somewhere (your metabolism in this case). So it would seem that the universe would've needed an initial input of energy to get things going.

But dark energy has changed this picture. It provides a sort of negative gravity that allows the expanding universe to be increasing in negative gravitational energy as other types of energy increase. Thus the traditional matter and energy in the universe could have arisen in concert with the creation of negative energy. Most cosmologists today think the total energy of the universe is zero.

I'm no expert, but this seems like it could be a counter argument for the need of a first mover.

Brett said...

While these sorts of debates can be fun for mental sparring, I find myself more bothered by them lately. Belief in God is a matter of faith. Always will be.

For instance, a popular analogy I hear from time to time in church settings goes something like this, "If you take apart a watch and then put the parts in a bag and shake it, would you ever come out with a working watch? Of course not, so order must be the result of God." Personally I think you would get a working watch given enough time. We don't really grasp what billions of years looks like. I don't know what processes God uses to do his work, but I find these arguments to logically prove God to be a bit off-putting.

David Friedman said...

In Aquinas' version of the argument, as I remember it, it was crucial that, in Aristotelian physics, something only moved if it was, at that moment, being moved. In Newtonian physics that is not the case--objects in motion remain in motion.

Aquinas, if I remember correctly, conceded the possibility of infinite regress in the non-simultaneous case, such as father, grandfather, great-grandfather, etc. Hence, if he had known about Newtonian physics, he would have had to abandon that argument.

Perhaps it can be saved by scientific arguments that eliminate infinite sequences, but I am by no means sure.