on certainty 10

10. I know that a sick man is lying here? Nonsense! I am sitting at his bedside, I am looking attentively into his face. – So I don’t know, then, that there is a sick man lying here? Neither the question nor the assertion makes sense. Any more than the assertion “I am here”, which I might yet use at any moment, if the suitable occasion presented itself. – Then is “2 x 2 + 4” nonsense in the same way, and not a proposition of arithmetic, apart from particular occasions? “2 x 2 = 4” is a true proposition of arithmetic – not “on particular occasions” nor “always” – but the spoken or written sentence “2 x 2 = 4” in Chinese might have a different meaning or be out and out nonsense, and from this is seen that it is only in use that a proposition has sense. And “I know that there’s a sick man lying here”, used in an unsuitable situation, seems not to be nonsense but rather seems matter-of-course, only because one can fairly easily imagine a situation to fit it, and one thinks that the words “I know that…..” are always in place where there is no doubt, and hence even where the expression of doubt would be unintelligible.

we do imagine situations for use

and it is only in use – that a proposition has sense –

which is to say – function

but just what that sense is –

what it amounts to –

is an uncertain matter –

Wittgenstein says 2 x 2 = 4 – is a true proposition of arithmetic

yes – it’s a proposition of arithmetic –

and it is true – if it is assented to

‘I know that …’ – is a claim to an authority –

the only authority – is authorship

it is unnecessary and irrelevant –

to state that you are the author – of your assertion

if ‘I know’ is meant as an expression of certainty –

it is always out of place

a proposition is a proposal –

and the ground of any proposal –

is uncertainty

doubt is only unintelligible –

to those who do not think

NB

2 x 2 = 4 –

is a proposal for a sign game –

a game of sign substitution

the game is defined by the ‘=’ sign –

the operation to the left of the ‘=’ sign –

can be substituted for the sign to the right –

that’s the game –

if you play the game –

as it is designed to be played

you play it without question –

there are no questions in the game –

the equal sign is not a question mark

however this is not to say –

the game itself – is without question –

its terms – its operations – its concepts –

are all – uncertain

the propositions of mathematics  –

are like any other proposition –

open to question –

open to doubt

© greg t. charlton. 2009.