What does 'better' mean? Ultimately it means more efficient at self-replication, but what might this mean in practice? This brings us to our third 'ingredient'. I referred to this as 'power', and you'll see why in a moment. When we discussed replication as a moulding process, we saw that the last step in the process must be the new copy's breaking free of the old mould. The time that this occupies may be influenced by a property which I shall call the 'stickiness' of the old mould. Suppose that in our population of replicators, which vary because of old copying errors back in their 'ancestry', some varieties happen to be more sticky than others. A very sticky variety clings to each new copy for an average time of more than an hour before it finally breaks free and the process can begin again. A less-sticky variety lets go of each new copy within a split second of its formation. Which of these two varieties will come to predominate in the population of replicators? There is no doubt about the answer. If this is the only property by which the two varieties differ, the sticky one is bound to become far less numerous in the population. The non-sticky one is churning out copies of non-sticky ones at thousands of times the rate that the sticky one is making copies of sticky ones. Varieties of intermediate stickiness will have intermediate rates of self-propagation. There will be an 'evolutionary trend' towards reduced stickiness.
