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Saturday, May 21, 2011

Difficulties with Aquinas' First Way of Arguing for God's Existence

I blogged a few weeks ago about Aquinas' First Way of arguing for God's existence, as described in Edward Feser's TLS. Aquinas thought the First Way (the Argument from Change) was the most evident of the arguments for God's existence. If I have it right, the basic idea is that every change is caused by (1) something else that changes or (2) something that does not change (which is called God). In other words, any change has an immediate causal chain that must terminate with an unchanged changer. For computer programmers, it's a bit like recursion, which must have a base case.

I do find myself running into problems when applying this to some real-life examples though. For example, I pick up a book. That change is caused by my flexing my arm muscles. That change is caused by neurons firing. Now we could continue to trace along the causal chain to molecules and atoms and thence to the unchanged changer. But could we not also trace down the causal chain to the human mind and say that the human mind, not God, is the unchanged changer in this case? But perhaps we need to ask a couple of other questions first: How can something immaterial like the mind cause a change in something material like the body (the "mind-body problem")? And is a thought in the mind something with its own immediate causal chain that we can trace down? I haven't read much on the philosophy of mind, so I don't have answers for these questions.

Another example that I have trouble with is this: Consider two billiard balls that hit each other and rebound. Can we use this example to argue for God's existence using the First Way? The change in question is that Ball A's velocity changes from 1 m/s to -1 m/s. This change is caused by Ball B. It's not clear to me how to follow the causal chain from this point. Do we say the next cause is the law of conservation of momentum (m1v1 + m2v2 = m1V1 + m2V2)? Or is this where we trace the causal chain down to molecules and atoms? If we do that, we will encounter other laws of physics, such as electromagnetic forces (F = kqQ/r^2, etc.). Do we count these laws as "causes" in the causal chain which themselves need to be explained by other causes? Have we shifted from arguing from change (the First Way) to arguing from cause (the Second Way), and is there a way for us to stick purely to the First Way?

I'm sure these questions have explanations that I'm not seeing. Let me know!

5 Comments:

  • Note to self: Following a cue ("transitions") from footnote 3.16 in TLS, when we get to molecules and atoms we can continue to use the First Way (argument from change) instead of shifting to the Second Way (argument from cause) if we employ the following language of "states":

    "The change in question is that Ball A's velocity changes from 1 m/s to -1 m/s. This change is caused by a change in the state of the molecules from MS1 to MS2. This change is caused by a change in the state of the atoms from AS1 to AS2. This change is caused by a change in the state of the subatomic particles from SS1 to SS2. And so on, to ever deeper levels of reality."

    So instead of my initial attempt at tracing the billiard-ball impact to one atom approaching another atom (which seems odd as a lot of atoms are involved in the impact), we consider *all* of the atoms involved in the impact: atomic-state 1 and atomic-state 2. This allows us to continue to speak of a change (e.g., in atomic state) being caused by another change (e.g., in subatomic state) (rather than by a physical law), and we can continue to use the language of the First Way ("change") without having to resort to that of the Second Way ("cause"). The benefit is that we keep the First Way distinct from the Second Way of arguing for God's existence.

    Perhaps not a big deal, but I found it interesting that using the language of "states" helps me to get past this difficulty.

    By Blogger Jonathan, at 5/22/2011 7:04 PM  

  • Regarding the Second Way, I have written a little on it, with an example, here.

    By Blogger Jonathan, at 5/23/2011 12:14 AM  

  • Why do you say that the mind is "immaterial" compared to the body?

    Does your analysis change if the the word "mind" is just a synonym for "the complete aggregate state of all of the physical objects that make up one person's consciousness"?

    http://www.amazon.com/Soul-Anna-Klane-Terrel-Miedaner/dp/0345271599 is a fun book along these lines if you want some fiction.

    By Anonymous David, at 5/25/2011 1:38 PM  

  • @David - I'm not an expert on this, but evidently one runs into problems if one takes "mind" to be purely physical. It's called the "mind-body problem". It's treated later on in this book that I'm reading.

    By Blogger Jonathan, at 7/21/2011 7:16 PM  

  • Regarding whether the mind is material or immaterial, I looked into this in The Last Superstition p.124-5 and a couple of arguments for the immateriality of the mind run like this: Think about triangularity (how a triangle's angles add up to 180 degrees, trigonometry, etc.). (1) Your mind is contemplating a perfect mathematical object, an exact concept. But material things are not perfectly exact in this way. Thus, your understanding is not a material thing. (2) You are thinking about a concept that is universal, i.e., not one particular triangle, but something about every triangle that's out there. But the neuroelectrical activity that is happening in your brain cannot be the universal triangularity, since it is one particular material thing in one particular brain. Thus, your thinking is not a material thing.

    By Blogger Jonathan, at 7/21/2011 11:58 PM  

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