Certainty and Truths

Philosophers have for centuries been keen to prove things that are certain and things that we think are true but we cannot be certain of.

David Hume

HUMES FORK REASON Analytical (N.B. Some synthetic knowledge is known through reason e.g. Causality) E.G. 2+2=4 All bachelors are unmarried All widows have dead husbands. A priori Relations of Ideas Necessary truths EXPERIENCE Synthetic E.G Grass is green Snow is white Toby is Head Boy A posteriori Matters of FACT Contingent Truths 4

Criticisms of Hume and certainty Quine: There is no such thing as a priori just truths that are known by lots of sense experience or a little bit. All analytical premise require an element of experience (e.g. If all men are mortal and Socrates is a man, then Socrates will die) 5

Locke (Empiricism) We can only have knowledge of something that can be experienced. The Strong Claim

We know things that are certain, we think things are true! What is known is certain and what we think to be true are different! Truth does not give us knowledge, certainty does. You cannot know something that is not true. I know the world is flat You can think a claim to be true I think that the world is flat. To have knowledge requires certainties. “indubitable” truths that are known logically a priori.

Descartes

Descartes Wanted to distinguish between truths and certainties about the way the world is. He wanted to make people aware that the only information that they should believe in are the Certain truths.

When people say they are certain, they can mean: 1. A psychological feeling (truth) (evil demon can trick you) 2. A logical certainty. Which truth/certainty gives us contingent and necessary truths? Descartes believes that we should only believe in__________ because______________

To work out if a claim gave us knowledge or truths, Descartes used The Cogito He tested every certainty proposition/claim against the certainty that occurred in this logical deduction of The Cogito. This formula set the bar for how few things in life we can be certain of.

Dr Jeremy Stangroom The little book of Philosophy Sum up Descartes’ views on certainty. Pick out 1 criticism of his argument.

Sceptics There are theorists out there who believe we can have no knowledge whatsoever and they are called sceptics. Bertrand Russell The Matrix

http://www.youtube.com/watch?v=lEr8hnvzeHU&feature=related

Read these 3 sceptical theories. Make brief notes on the 3 theories.

Further reading Metaphysics Scepticism Descartes Russell Criticisms of empiricism and sense perception Year 12 online classroom Philosophy