Why can't a being which is not Pure Act be uncaused?

[Pieman333272]

I’ve been reading about St. Thomas Aquinas’ five ways and idea of God as Pure Act recently. I find much of it very convincing and philosophically strong, but I was wondering one thing in relation to some of his arguments. In the case of his first two ways, Aquinas tries to prove a being which is uncaused and unchanged but which can still cause other beings to exist and change. Now I think his arguments succeed in proving that, but what I don’t understand is why an uncaused being has to be Pure Act, rather than a mixture of actuality and potentiality whose actuality is uncaused. I know this is somewhat basic, but I still don’t completely get it. Would anybody like to explain?

 

[theophilus1985]

God Is Pure Act because he is absolutely perfect. He cannot grow in wisdom, goodness, justice, etc. He is everything he ever has been or ever will be. Creatures on the other hand are a mixture of actuality and potentiality. We change. We can grow in wisdom, goodness, justice, etc. In fact, for creatures potentiality is prior to actuality. But in order for change to occur in any object, something must act upon it. A ball at point A has the potential to roll across the floor and arrive at point B, but something else must act upon it in order for this secondary state to be actualized. So we have going backwards a chain in causation, of creatures acting and being acted upon until we arrive at that Being who acts but is not acted upon. I think that is what the scholastic philosophers meant.

 

[Linusthe2nd]

I’ve been reading about St. Thomas Aquinas’ five ways and idea of God as Pure Act recently. I find much of it very convincing and philosophically strong, but I was wondering one thing in relation to some of his arguments. In the case of his first two ways, Aquinas tries to prove a being which is uncaused and unchanged but which can still cause other beings to exist and change. Now I think his arguments succeed in proving that, but what I don’t understand is why an uncaused being has to be Pure Act, rather than a mixture of actuality and potentiality whose actuality is uncaused. I know this is somewhat basic, but I still don’t completely get it. Would anybody like to explain?

I think if you read " Aquinas " by Dr. Edward Feser that it will become clear. You can get it cheaply on Amozon. You may even find a copy at your local library.

The long and short of it is that beings which are moved from potentiality to actuality must be moved to actuality by a being which is in actuality. But if it has itself been moved from potentiality to actuality we become involved in a situation which is endless unless we arrive at a First Cause which is Pure Act. An endless series of change/movement cannot exist because then there would be no First Cause and thus no second or subsequent causes. Thus, nothing would exist, which is clearly not true, because the universe does exist. Therefore the First Cause exists and this we call God. Linus2nd