Where it all came from
St. Thomas Aquinas developed an argument that the Ancient Greeks had used for the existence of God. He began his argument by looking at the natural world through his sense's.
His first argument - The Prime Mover
Everything in existence moves and/or has the potential to change. For example a log of wood has the potential to set fire. Change is always caused by something, nothing is able to move on it's own. Therefore there must be a prime mover that has caused this. This prime mover is God.
His second argument- The Uncased Cause
Cause and Effect are naturally occuring in our world. Whatever happens is the effect of something else. We are unable to say that something can cause itself, that would mean that something must exist before it exists, which is logically impossible. Therefore there needs to be an uncased cause. The uncased cause is God.
His third argument- A neccessary being (contingenc
Nothing in our world is permanent. Everything is contingent, it exists but could also not exist. That means it's possible that there was a time when nothing existed. Because we know that it is impossible for nothing to come from nothing, it means that something had to exist prior to everything else. There must be a neccessary being, which all contingent being came from this neccessary being. The neccessary being is God.
Strenghts and weaknesses
Strengths: It is logical, there are a variety of similar views
Weaknesses: There is no solid evidence. Everything goes to go. Aquinas contradicts himself.
The 18th century philosopher David Hume required facts rather than the observations that Aquinas made. Hume started with the existence of the universe. He believed that all knowledge and ideas, no matter how complex, can be resulted to some experience that our senses have provided. He concludes that humans think that they know a great deal more about the eternal wold than is wanted. Humans allow imagination to make a connection between cause and effect. Aquinas is wrong for making this connection. They are two separate events.
Immanuel Kant (1724-1804) argued the existence of of a supreme being as a first cause of the universe. He argued that the idea that every event must have a first cause only applied to the world of some experience. He did not accept any justification for the conclusion that God caused the universe to begin. God would be a casual being outside space and time as we understand it.