Definitions

True in the virtue of the meaning of the words

Ex. A bachelor is an unmarried man & Triangles have 3 sides

They cannot be denied without a logical contradiction

True in virtue if how the world is

Ex. Grass is green & Water boils at 100 °c

Denial does not lead to a logical contradiction

Can be acquireed without experience of the external world - through thought alone

Ex. Working out 9 × 7 = 63

Can only be acquired from experience of the external world

Ex. Doing an experiment to discover boiling point of water

A Priori method for gaining knowledge

The ability to know something is true just by thinking about it

Ex. Descartes Cogito Argument

Method of deriving true propositions from other true propositions using reason

You can deduce statement 3

1. If A is true then B is true

2. A is true

3. Therefore B is true

Not all a priori knowledge is of analytic truths

There is at least one synthetic truth that can be known a priori using intuition and deduction

All a priori knowledge is of analytic truths

There is no synthetic a priori knowledge

It’s a contradiction to deny them. They’re “true in all possible worlds”

2 + 2 = 4

Truths which simply happen to be the case, they’re true but we can logically imagine a world where they’re false

PSC is on the north side of Winchester BUT we can conceive of a world where it’s on the southern side.

We can’t conceive of a world where parallel lines cross.