Take yesterday, for example. Having spent the bus journey home listening to some tin-pot intellectual (who later turned out to be a columnist for the Daily Mail; go figure) mincing on about being a 'global warming sceptic' and making some of the most repulsive discriminatory statements, I began to wonder about the nature of discrimination.

One of the things that has fascinated me from an early age is the thought that us humans are animals. I try to figure out if we are special animals - look! Beethoven's 9th! The Beach Boys! Global warfare! Bakewell tarts! - or if I'm just incapable of making an objective decision being as I am a member of the human race; maybe dogs' dependance on smell makes them think they are the dominant species - I don't know, I can't smell what they do - or perhaps its the Spanish Flu which thinks it holds sway since it's capable of bringing whole human civilisations to its knees.

(We'll get back to discrimination in a paragraph or two; hang in there)

It was the notion that so much of what attracts us to one another is based on smell that first made me think that we were much closer to what we regard as more base animals than we'd like to believe. I'm interested in the extent to which those things that we regard as being higher brain functions are in fact mere impulses triggered by such elemental forces such as smell.

I like the idea - one which I'm proud to say I formulated for myself at a young age - that anything that we regard as evil is basically something which harms society. This concept is codified in law and religious dogma, but it driven by basic, Darwinian ideals of evolution. The thing that drives us, we're told, is the need to procreate. Anything which arrests the development of human society or the evolution of the species is viewed as Bad.

So what does this all have to do with a Daily Mail columnist? The thought that occurred to me was, what if discrimination has a good, evolutionary reason to exist? Society tells us that to make generalisations is wrong, that we should avoid using our experiences of the few to make judgements about the many. I've never found good reason to argue with this.

Before mankind became civilised (and I use that term without apology or sarcasm, hoping that you will know what I mean) if an individual ate a red mushroom which subsequently made him ill, he would be justified then in viewing all red mushrooms as suspect; he could die otherwise. (An aside: the first mushroom I could name as a child was "Fly Agaric", that terrifying white spotted red mushroom which, while not fatal, shouldn't be included in your next mushroom omelette) I've chosen to discriminate by colour deliberately, since this is the type of discrimination that quite rightly excites the most controversy today.

This doesn't license us to hate or damn Jews, gays, blacks, Tories, women, men, Chelsea supporters or any other group of people you care to name - let's face it, the Daily Mail wasn't there telling all the other homo erectus that red mushrooms were comin' over here, takin' all the white mushrooms' jobs - but rather it should give us cause not to be slaves to evolutionary instinct. We do seem to have special skills as humans, and one of them is the capacity to inform our instincts with something approaching rational thought. Let's do that.