Aristotle, much like a natural scientist, believed that we could learn about our world and the very essence of things within our world through observation.
Aristotle, much like a natural scientist, believed that we could learn about our world and the very essence of things within our world through observation.As a marine biologist might observe and catalog certain marine life in an attempt to gain insight into that specific thing's existence, so too did Aristotle observe the physical world around him in order to gain insight into his world.
Empirical data is that which can be sensed and typically tested.
Unlike Anselm, who was a rationalist, Aquinas will not rely on non-empirical evidence (such as the definition of the term "God" or "perfection") to demonstrate God's existence. Thomas will observe the physical world around him and, moving from effect to cause, will try try to explain why things are the way they are.
We might say that someone is at the peak of their game or that someone is the best at what they do.
We might say It just does not get any better than this if we are are having a very enjoyable time.
Working from the assumption that if a thing is in motion then it has been caused to be in motion by another thing, Aquinas also notes that an infinite chain of things-in-motion and things-causing-things-to-be-in-motion can not be correct.
If an infinite chain or regression existed among things-in-motion and things-causing-things-to-be-in-motion then we could not account for the motion we observe.For Aquinas the term motion meant not just motion as with billiard balls moving from point A to point B or a thing literally moving from one place to another.Another sense of the term motion is one that appreciates the Aristotelian sense of moving from a state of potentiality towards a state of actuality.Thus, there must be a First Cause which set all other things in motion. So, in order to account for the motion that we observe, it is necessary to posit a beginning to the cause and effect relationship underlying the observed motion. The Unmoved Mover is that being whom set all other entities in motion and is the cause of all other beings.It is also necessary to claim that the First Cause has not been caused by some other thing. For Aquinas, the Unmoved Mover is that which we call God.Thomas' Five Ways is the concept of potentiality and actuality.Aristotle observed that things/substances strive from an incomplete state to a complete state. The more complete a thing is, the better an instance of that thing it is.If we move backwards from the things we observe in motion to their cause, and then to that cause of motion within those things that caused motion, and so on, then we could continuing moving backwards ad infinitum.It would be like trying to count all of the points in a line segment, moving from point B to point A. Yet point A must exist as we know there is a line segment.He will assert God as the ultimate Cause of all that is.For Aquinas, the assertion of God as One last notion that is central to St.