What is the difference between A Priori and A Posteriori? What are analytic and synthetic statements?

What is the difference between A Priori and A Posteriori statements or arguments?

A Posteriori statements are statements or truths ‘post experience’. In other words, you have to have experienced something in order to make the claim. Remember it because ‘post’ means after – after experience.

A Priori Philosophical statements are based on logic

A Priori statements are usually ‘analytic’ in nature and A Posteriori statements are usually ‘synthetic’ in nature.

What is an analytic statement?

An analytic statement is one that is analytically true i.e. it is true within itself. An example of this is the term ‘bachelor’. A bachelor is an unmarried male. The term bachelor entails ‘maleness’ and ‘unmarriedness’.  If you told me ‘John is a bachelor’ I would not have to meet John to know that he was unmarried and that he was a man. That is because the term ‘bachelor’ itself tells me these things analytically.

What is a synthetic statement?

A synthetic statement is something that is true by the way it relates to the world. For example, ‘the cat is black’ is a synthetic statement.

Now, let’s say that ‘catness’ entailed ‘blackness’, and Timmy was a cat. He would therefore be black, and this would be analytic. However, not all cats are black.  Therefore, the statement ‘the cat is black’ is synthetic.

Is the statement ‘God Exists’ A Priori or A Posteriori?

This is a trick question, because the answer is both!

If we argue that ‘God exists’ from Design in the world (Paley), we are presenting a A Posteriori argument.  That is because I have to experience the design in the world to be able to present the argument for God as a designer.

If we say that ‘God’ exists arguing ontologically, we are presenting an A Priori analytic argument. This is because, according to Anselm, existence is a logical necessity for God.


The Ontological Argument for the Existence of God

The Ontological argument for God’s existence is often the most difficult to understand.  I would like to simplify the argument and break it down into easy understandable steps! The Ontological argument is a popular exam or essay question in AS, A-Level and degree level philosophy.

The Ontological argument was first asserted by St. Anselm. It is the only A Priori argument for God’s existence. That means that it derives from logic and reasoning rather than from experience.

The Ontological argument according to Anselm in 4 easy steps…

1. Anselm defined God as ‘a being than which nothing greater can be conceived’.

2. If we conceive of a God that has existence, and a God that does not have existence, which would be greater

3. If God with ‘existence’ is greater than God without existence, it follows that God must have existence in order to be ‘a being than which nothing greater can be conceived’.

4. Therefore, God must exist.

Get it?  No? Ok, imagine a Mars bar in your mind. If you look in the cupboard and find a Mars bar that actually exists, you can eat the one that has existence, but not the one in the mind. Therefore the Mars bar in reality is greater than the one in the mind.

Criticisms of Anselm’s Ontological Argument

In Anselm’s argument, God appears to have necessary (rather than contingent) existence. Whether or not necessary existence is possible is another matter. Also, it could follow that using Anselm’s logic, you could conceive of anything at all coming into existence! If you are interested in looking at the criticisms of the Ontological argument in more detail, have a look at Gaunilo. He criticised Anselm by saying that using this logic, he could think about the most perfect conceivable Island, and that the one in reality would be more perfect than the one in the mind, therefore it must exist!

Further Reading on the Ontological Argument for God’s Existence

An excellent book on the arguments for God’s existence is John Hick. For more further reading, click here.