The 'theory' of 'evolution'.

Problems always arise when scientists use a term in a specific way that differs from how the term is used by the general public. Unfortunately both 'evolution' and 'theory' fall into this category (and so the phrase 'the theory of evolution' is just trouble waiting to happen). As we will see in a future lecture, scientists use the word theory to describe a hypothesis that has held up to extensive testing. In general speech, theory tends to mean something much more speculative. ('I don't know why the mail is late today but I have a theory').

Things are perhaps worse when we come to the word evolution itself. Evolution, for scientists, is a measurable change in the heritable traits of a population over successive generations. That's it. And it isn't a theory, it's a fact, because we can measure it. In general speech however evolution is often confused with Darwin's theory of evolution by natural selection. On top of this there is an additional misconception that evolution must involve improvement or progress.

I always thought Pearl Jam and Todd McFarlane had this latter issue in mind when they did the 'Do the Evolution' Video. Comments at the Sony Music site suggest otherwise.