Aquinas's Third Way

Overview

Recall questions on contingent and necessary beings and on why the argument from contingency is a posteriori.

What you need to know

Answer each one before you reveal it.

Questions from this subtopic

Each one with the model answer underneath.

1. 1

   What is another name for Aquinas' Third Way, based on the key concepts it employs?

   Model answer

   The cosmological argument from contingency and necessity.

2. 2

   Define a contingent being.

   Model answer

   A being that exists but could possibly not exist; its existence depends on something else.

3. 3

   What is a necessary being?

   Model answer

   A being that cannot not exist; it exists by its own nature and does not depend on anything else for its existence.

4. 4

   Why is Aquinas' Third Way classified as an a posteriori argument?

   Model answer

   Because it begins from observation of the world rather than from pure reason alone.

5. 5

   What does Aquinas observe about the things that exist in the world?

   Model answer

   That everything in the world is contingent: things come into existence and pass out of existence.

6. 6

   According to Aquinas, what would follow if everything that exists were contingent?

   Model answer

   There would have been a time when nothing existed.

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