The traditional view of the history of life is that everything moves up and out, that you start from a few simple things, and you move up and out to more complex things. Under that view, the history of life is progressive and predictable, and humans or something like us would eventually emerge. And that’s a comforting notion. The Burgess Shale really proves its falsity, because the great surprise of the Burgess Shale — and by the way, the Burgess Shale was discovered in 1909 but interpreted very conventionally. The man who first found these organisms just shoehorned them all into modern groups and described them as simple, primitive, precursors of forms that came later. But they have been intensively restudied by a team of British paleontologists over the last 25 to 30 years, who’ve completely inverted this interpretation and shown that the Burgess Shale is not a few simple precursive things that came later, but actually represents an enormous initial explosion of evolutionary diversification. So that in fact, there’s more anatomical diversity in the Burgess Shale than there are in all the world’s oceans today. The history of life is a reduction of initial possibilities to just a few surviving groups. Now, each of these surviving groups may generate millions of species, like the insects, but they don’t, again, produce fundamentally new anatomical and body plans, so that in fact the history of life has been limitation. Now you could give a conventional argument to that and say, “All right, there was 100 and only ten survived, but those ten were predictably superior, so there still is a progressive directionality to the history of life.” But in fact, without going into details, a strong argument can be made that the reduction of 100 initial possibilities to ten or so was the analogue of a bingo game, a grand-scale lottery. In fact any ten of the 100 could have made it. If you could rewind the tape of life, erasing what actually happened and let it run again, you’d get a different set of ten each time. There are 17 trillion different combinations of ten that you can take from a group of 100. So if the lottery model is right, any lineage that exists on Earth now is lucky to be here, in that sense that it’s one of the survivors of the great Burgess Shale lottery. Of course we’re one of those lineages, we’re not separate from that reinterpretation.  So under this reinterpretation inspired by the Burgess Shale, we — along with all other lineages — are lucky to be here in that sense. Most subsets of survivors in these hypothetical replays would not include the lineage that gave rise to us.