We are lucky to be alive

If ever I feel the temptation to feel sorry for myself, I like to remind myself of the idea demonstrated in the cartoon below that shows how in order for us to be alive at all, every single one of the millions of our ancestors, all the way back to the first living organism, had to be survive long enough to reproduce. If, at an early stage of that sequence, one were to put odds on that happening, the chances against it are enormous. And yet here we are.


This is of course, not a paradox at all. If any one of our putative ancestors had struck out and been snuffed out early in life, then we would not be here to look back in wonder. But despite my conscious awareness of the lack of a paradox, it still kind of amazes me, so I can kind of understand why some people think that a god must have planned the whole thing, even though that is preposterous.

But what this knowledge should do is remind us that small probability events happen all the time and are not always a puzzle that needs explaining, anymore than there needs to be an explanation why any given person won the lottery even though the odds against that person doing so were so tiny.

One should bear this in mind whenever advocates of intelligent design or theistic evolution claim that the existence of the universe in its present form is so unlikely to have occurred according to the laws of physics that there must have been some form of divine intervention.


  1. says

    It may help that just by sheer numbers alone (you have 2 parents, 4 grandparents, 8 great-grandparents, and so on) the doubling has to stop because it exceeds the number of living people so a great many of your ancestors have to repeat several times in your family tree.

  2. DonDueed says

    Well, I haven’t reproduced and am not likely to. The winning streak ends here!


  3. Beth says

    The problem, as I see it, is that ‘coincidence happens’ is any better than ‘shit happens’ is any better than ‘god did it’ in terms of explanatory power.

    I do see the breadth of evolution as inspiring, but I don’t see a designer as a ‘preposterous’ idea. Is our world a simulation created by other conscious beings in other dimensions? I don’t see that as being any more preposterous an explanation of how everything we are conscious of came to exist than ‘shit happens’, which is my assessment of the big bang hypothesis.

  4. Lofty says

    Of course it’s not just about meeee, it’s about the genetic material I share to varying degrees across the whole biosphere. I’m not a special end point of evolution, that’s religious thinking.

  5. Beth says


    If you don’t reproduce, you’re an end point of evolution -- i.e. no one descends from you. 🙂

  6. Jockaira says

    small probability events happen all the time

    The larger probabiliity is that life-forms will not be “born” but if so, it is not probable they will survive to reproduce. It can be mind-boggling to consider the numbers that might have been.

    Included in that larger probability is that once started, life will continue until it exhausts all possibilities for existence.

    The greatest human achievement perhaps is the enhancement of these positive probabilities to ensure long life and reproduction.

    And of course, the Universe doesn’t care.

  7. Marshall says

    A good way to put this (which is basically the anthropic principle) is with the analogy of tossing a pebble into a room. The pebble lands at some position (x,y), the exact position of which essentially has probably p(x,y) = 0. Was it divine intervention that caused the pebble to land in that exact spot?

    (P.S I can’t login view any of the options, G+, G, or wordpress. Don’t have Yahoo account so didn’t test that.)

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