Let’s catch up so that we’re not in danger of forgetting where we came from, where we are, and where we’re going. I do not mean here to give complete arguments. That has already been done in the original posts. What follows is only a sketch to reorient and reinvigorate us. Don’t be lazy.
Does God exist? How do we know? Given the logical implications of answering those questions, how do we explain what can we know about God? What can we know about God? Well, some things, but not every thing. But more than you’d guess. These questions, all worthy and deserving of our attention, form the discourse of Book One of SCG. Let’s review.
Our efforts will not be in vain. From Chapter 3: “Now in those things which we hold about God there is truth in two ways. For certain things that are true about God wholly surpass the capability of human reason, for instance that God is three and one: while there are certain things to which even natural reason can attain, for instance that God is, that God is one, and others like these, which even the philosophers proved demonstratively of God, being guided by the light of natural reason.”
Let’s don’t be lazy; let’s attack each point assiduously, as argued in Chapter 4. Why? Because “the checking of presumption which is the mother of error” Chapter 5. Repeat that thrice. Most of what we believe is given to us. Let’s think things through, guided by those of superior intelligence. God is an embarrassing subject for our world, except to denigrate religion or sneer at theology, these unthinking irrational ill-educated attitudes being thought a mark of sophistication. Don’t be lazy.
The proof, using only reason and not a whit of divine revelation (beyond that which we all possess) which forms the backbone of Aquinas’s efforts, is that of first motion, which begins in Chapter 13 (part 2, part 3, part 4, part 5; don’t be lazy).
3 The first way is as follows. Whatever is in motion is moved by another: and it is clear to the sense that something, the sun for instance, is in motion. Therefore it is set in motion by something else moving it. Now that which moves it is itself either moved or not. If it be not moved, then the point is proved that we must needs postulate an immovable mover: and this we call God. If, however, it be moved, it is moved by another mover. Either, therefore, we must proceed to infinity, or we must come to an immovable mover. But it is not possible to proceed to infinity. Therefore it is necessary to postulate an immovable mover.
This simple and quite beautiful eminently reasonable and (thus far?) irrefutable argument has never stopped being misunderstood. Aquinas, and we following him, went to great pains to show that this movement is here-and-now. That which accounts for how any movement, which is to say how any change, happens must be because of a First Mover, an Unchanging Changer.
From this argument we learned (among other things) the concepts of act and potential. Something actual changes a thing from one “state” to another “state”, which before the change was only a potential. It cannot be the potential that is an efficient cause, it must be something actual.
What follows from this is that, because for any and all change there must be a First Changer, that God is not only “everywhere”—but not in the pagan sense; in the sense that if God did not exist, the universe would immediately cease—but God is also eternal, outside time, because time is the measure of movement, and God is Unmoving, Chapter 15. Few of these terms carry the same colloquial definitions we ordinarily carry, so don’t be lazy: read the original argument.
Another consequence is that God does not have any passive potentiality, Chapter 16.
2 For everything in whose substance there is an admixture of potentiality, is possibly non-existent as regards whatever it has of potentiality, for that which may possibly be may possibly not be. Now God in Himself cannot not be, since He is eternal. Therefore in God there is no potentiality to be
Not surprisingly, from these we learn that God is not made of matter. He is not physical stuff, Chapter 17. God is not the god of the atheists; He is not a clever, long-lived alien being composed (say) of energy fields. God is beyond matter: He is spirit.
It immediately follows that God is not made of parts, that he is “simple”, Chapter 18.
1 For in every composite thing there must needs be act and potentiality: since several things cannot become one simply, unless there be something actual there and something else potential. Because those things that are actually, are not united except as an assemblage or group, which are not one simply. In these moreover the very parts that are gathered together are as a potentiality in relation to the union: for they are actually united after being potentially unitable. But in God there is no potentiality. Therefore in Him there is no composition.
Another consequence: there is nothing in God against Nature, Chapter 19, and that God is not a body, Chapter 20, the simplest demonstration of which is, “For since every body is a continuous substance, it is composite and has parts. Now God is not composite, as we have shown. Therefore He is not a body.”
This brings us up to date. God exists, is responsible for the universe remaining in existence and is the ultimate cause of all change, that He is eternal, that He has no potential, that He is not made of stuff and is not a body. Well, fine. But that doesn’t tell us much. This could all describe the some kind of weird immaterial physical uber-field. Though we’ve gone a great distance, we haven’t really done much. We haven’t come close to describing God in full.
But we still have 80 chapters to go! Don’t be lazy.