Tuesday, 5 September 2017


William of Ockham (1287-1347) invented the safety razor, often wrongly attributed to King C. Gillette (1855-1932), who of course invented the waistcoat, but (Ed: shome mishtake shurely?)
Ah, yes.  William of Ockham (1287-1347) formulated the principle that became known as Occam’s Razor.  It’s called a razor because it shaves away extraneous matter.  (Why Ockham became Occam is anyone’s guess; did medieval keyboards lack a K and an H?)
Occam’s Razor can be expressed in many ways.  Here are two:
1.     The law of economy of hypothesis (which I might have just made up) states that, of a number of solutions to a given problem, the correct one is that which requires the least number of assumptions.
2.     Z, on having heard me dissert on this, offered the 21st century version acronymised in this post’s title.
Anyway, it sprang uninvited into my mind after an amusing Facebok conversation about the following conundrum:

1 + 4 = 5
2 + 5 = 12
3 + 6 = 21
5 + 8 = ? 

The answer, of course, is 34, but a lot of people opted for 45.  I challenged this, and it was suggested that, given that the = sign in this context obviously doesn’t mean what it usually means, then the operators are up for grabs and the + sign can therefore be fairly interpreted as a * (multiply) sign, in which case you do get 45.
That’s where William nudged me in the ribs.  Oy, he said, one mistake’s enough, why let another one in? 
I thought I’d scored a point, but now I wonder: if + doesn’t mean +, and = doesn’t mean =, who’s to say what 1, 2, 3, 4, 5 and the rest mean?  Whereof one cannot speak, thereof one must be silent.


  1. Hang on, so they're saying the question is 5x8+5? But.....

  2. It's too late for me to reconstruct their perverted logic, let alone the non-maths. My point was just that meaning has to be founded somewhere, or we're fucked. As Wittgenstein pointed out.

  3. Right, looked again. The argument went: 1*4+1=5;2*5+2=12; 3*6+3=21; 5*8+5=45.
    I rest my (and Occam's) original case. You shouldn't assume more than you have to.