Types of knowledge and propositions

(Originally Written September 11, 2006 in Epistemology)

A priori knowledge

Necessary truths - propositions that cannot be false
contingent truths - propositions that are true, but could be false

The distinction betwixt necessary truths and contingent truths is a metaphysical one.

Analytic propositions - true by way of their meaning
Synthetic propositions - true through their relation to the world

The distinction betwixt analytic and synthetic propositions is a semantic one.

A priori knowledge - knowledge prior to experience
A posteriori knowledge - knowledge through experience

The distinction betwixt the two is an epistemological one.

Kant:

Analytic a priori - i.e. Triangles are three sided
Synthetic a priori - i.e. 5+7=12, causality
Synthetic a posteriori - i.e. the house is brown

There is no a posteriori analytic propositions

A.J. Ayer

-a strong empiricist
-a logical positivist
-Held that in order for a statement to be cognitively meaningful it had to be either analytically true or empirically meaningful.
-Held that an en empiricists must regard analytic propositions as either:
1) Not necessary (John Stuart Mill)
2) Devoid of factual content (Ayer)