Someone being described as a “glass half-full” or “glass half-empty” sort of person is something that one hears increasingly frequently. I was recently discussing this with a friend and we both agreed that the analogy was unhelpful. First it supports a drastically simplistic and binary view of people having fixed attitudes and behaviours in all circumstances. Day-to-day observation suggests on the contrary that a person my be an avid optimist one day about one thing and a manic pessimist the next day about another thing. This rather shallow type of characterisation rather reminds me of some of the subjects I touched on in The Big Picture and Pigeonholing – A tragedy some time ago.

However, there is a more fundamental consideration; wilful inaccuracy. A glass that is half empty is also half full; that’s the definition of a half. Either description is 100% valid and therefore logically can tell you nothing about the person’s mindset.

Instead what might be more apposite is to adopt a different way to divide sheep from goats. This is still rather too binary for my taste, but at least it has the merit of a greater degree of rigour. I propose dividing people according to how they view a glass that is three quarters empty:

• I still have some left: optimist
• There isn’t very much left: pessimist

I think that all of our lives would be much the better for adopting this simple principle.

Accordingly, I am going to submit this recommendation to the International Standards Organisation for their urgent consideration. I’ll make sure that I keep readers up-to-date with how my submission progresses.