A staggeringlly large number of variables, both genetic and environmental, converge to create each individual's character. The perceptions we form of each other are usually gross oversimplifications. This idea can be illustrated very clearly with a deck of playing cards. A deck of 52 playing cards can be shuffled into a great number of different sequences. There are approximately 8 times ten to the power of 67 different possible orders that a deck can have. There are only a mere 10 to the power of 20 stars in the universe. In contrast, there are approximately 20,000 genes in the human genome and like a deck of cards these get “shuffled”, each time we reproduce.1 Geneticists estimate that there may be roughly 3 to the power of 1.42 million different combinations of possible human genomes. This number dwarves the number of atoms in the universe by an unimaginably large margin. Genetics aside, there are obviously countless other environmental factors that can shape an individuals personality, a huge range of information, ideas, beliefs, practices and values that exist within each culture, the complex flexible relationships that each person has with their family, friends, community, state or entire species and what they learn from each of these groups. The question of why each person has the characteristics that they do, is totally and utterly chaotic, it is far too complicated for any mere mortal to comprehend. Our lives are chaos.
There is a card trick known as the colour changing deck. It's method is very simple, but also surprisingly deceptive. The basic principle is that the human brain overgeneralises and extrapolates limited information. The entire deck is all one colour except for several cards near the top, which are of a contrasting colour. The pack is usually shuffled with the faces towards the spectators, however the top few cards is retained in position with sleight of hand. These contrasting ones can be spread slightly to non-verbally suggest the entire deck is this colour. The effect of the colour change can be achieved in several ways. A common method is to discretely “palm” a card into one of the magician's hands and then to place it on the top in the action of apparently wiping the deck with this hand. The secret of this trick sounds very simple, but I can tell you from experience that it fools many people. This principle of overgeneralisation is exploited by magicians frequently in sleight of hand and stage illusions. I work as a professional magician and my career entirely depends on the faults in the human mind and senses. After doing this for years I am still surprised by how often people fail to see things that happen right in front of them. We frequently make these sorts of cognitive/perceptial errors when we form judgements about the people around us.
I recently had an assignment in a unit on historiography at the University of Sydney in which I was asked to "historicise myself" in 350 words, in other words, to summarise the historical circumstances that created my character. To expect someone to boil the answer to such an immense question down to several hundred words is so incredibly shallow and irrational that it is only marginally less stupid than racism.