Tuesday, July 07, 2009

AND AND AND AND OR OR OR

By adding two other conjunctions, and and or, Mr Russell opens up a new domain to logic. The signs and and or follow the same laws as the two signs x and +, that is to say, the commutative, associative, & distributive laws. Thus and represents logical multiplication, while or represents logical addition. This, again, is most interesting

Whatever possessed anybody to use the words and and/or or? Especially since and means add in many contexts

It must sound like a wail like in French? – the quote comes from PoincarĂ©’s Science & Method

I love that ‘most interesting’

PoincarĂ© himself was a most interesting, & kindly sounding man – I really appreciate his insistence that the teaching of maths should start with the concrete & then move to the abstract



It must be 35 years ago. Theres a gentleman I know by sight as a regular passenger on the bus. Past middle age, well dressed, always wears a hat – a brown trilby (like Denis Thatcher)

One afternoon he is forced to take the seat next to me – no regular passenger on the old Routemasters took an outside seat on the top deck. Always bag an inside seat when you can, to avoid the bumps to your shoulder from people passing up & down the gangway

He was clearly – but discreetly – following my progress with the crossword puzzle. When it was plain that the final clue had defeated me, he could not resist

Sorry to interrupt – can you really not do that one?

I conceded defeat

Poincaré

To tell the truth, I was a teeny bit shocked. In the same way that a small child is shocked – hand to mouth, eyes wide – then giggles, with the realisation that a Grown Up has said something THAT’S RUDE

I cannot remember the clue in detail, but the cryptic bit was something like chamber pot in the market square

To this day I am a teeny bit shocked – or at least surprised – if the Top Peoples Paper is ever so slightly rude with its clues

And I can almost never think of Poincaré without thinking of the porcelain under the bed