Marcelo Gleiser, Appleton Professor of Natural Philosophy and Professor of Physics and Astronomy at Dartmouth College, pops the question:
If you think there is some kind of cosmic teleology, a sense of purpose that inevitably leads to life, you are saying we are inevitable. If you don't, if you say we are the result of a series of cosmic accidents, then you believe we aren't inevitable. We just happened. This latter position is often accused of being nihilistic: if we are the results of accidents, what's the point of being alive?
Which just goes to show how very different the framing assumptions can be with which different people operate. The logic of that final 'if etc... what's the point?'-sequence eludes me. It implies that there can only be a point in being alive if there's some preordained metaphysical purpose. Goodness, haven't the people who think like this ever heard of the Lord's Test? (Ummm... no, not that Lord, this one.) Or the North Sea Jazz Festival? Or loving their children? Or working on a project the outcome of which is important to them?
This is the gist of what Gleiser himself goes on to say (though, strangely, he fails to mention the Lord's Test): we can have a sense of purpose without being the elements in a grand plan. He narrows things down a bit too much for my liking, saying 'our purpose comes from our rarity'. I think we can have worthwhile purposes even if it's the case that there's a lot more intelligent life knocking about out there.
