Explain Hume's distinction between matters of fact and relations of ideas (5)

David Hume, an empiricist, separated knowledge into categories - "matters of fact" and "relations of ideas".

Hume argues that every affirmation which is certain, such as geometry, arithmetic and algebra, fall under "relations of ideas". For example, the fact that the square to the hypotenuse is equal to the square of two sides is a relation of ideas. These facts are a priori knowledge and therefore can be known simply through pure reasoning. According to Hume, they are not significant and do not tell us anything about the world. 

"Matters of fact", on the other hand, contain a posteriori knowledge and are therefore synthetic propositions that tell us about the world. They are not certain and are based on sensory experience and cause and effect. Matters of fact are contingent truths, such as that Donald Trump is the President of the USA - this is not always going to be true.