But even if we grant "Darwin's powerful crane" the power to explain the diversity of life on our planet, it can't explain the origin of life, or as it turns out, other equally improbable events. For this Dawkins turns to the anthropic principle. I've read this section of the book several times, and though I understand his description of the concept, I can't see how it's any kind of an explanation. If anything, it works against the case Dawkins is trying to make.
Nevertheless, it may be that the origin of life is not the only major gap in the evolutionary story that is bridged by sheer luck, anthropically justified. For example, my colleague Mark Ridley in Mendel's Demon has suggested that the origin of the eucaryotic cell (our kind of cell, with a nucleus and various other complicated features such as mitochondria, which are not present in bacteria) was an even more momentous, difficult and statistically improbable step than the origin of life. The origin of consciousness might be another major gap whose bridging was of the same order of improbability. One-off events like this might be explained by the anthropic principle, along the following lines. There are billions of planets that have developed life at the level of bacteria, but only a fraction of these life forms ever made it across the gap to something like the eucaryotic cell. And of these, a yet smaller fraction managed to cross the later Rubicon to consciousness. If both of these are one-off events, we are not dealing with a ubiquitous and all-pervading process, as we are with ordinary, run-of-the-mill biological adaptation. The anthropic principle states that, since we are alive, eucaryotic and conscious, our planet has to be one of the intensely rare planets that has bridged all three gaps.
Natural selection works because it is a cumulative one-way street to improvement. It needs some luck to get started, and the 'billions of planets' anthropic principle grants it that luck. Maybe a few later gaps in the evolutionary story also need major infusions of luck, with anthropic justification. But whatever else we may say, design certainly does not work as an explanation for life, because design is ultimately not cumulative and it therefore raises bigger questions than it answers . . . (pp. 140-141)
In spite of Dawkins' best efforts to avoid the chance v. design dilemma, that's exactly what he's left with. Major infusions of luck indeed. Those bigger questions raised by design that he returns to time and time again revolve around the familiar theme "Who designed the designer?" No matter how improbable the naturalistic explanation, the idea of a designer is always more improbable. Dawkins has faith that science will eventually come up with a Theory of Everything that will explain the origin of life and equally perplexing questions of the origin of matter. He can conceive of a universe with a definite though still-as-yet unexplained beginning that's destined to expand forever, but he can not (or will not) conceive of a creator God without beginning or end. Here also, to appreciate his power and goodness, one must be "steeped" and "immersed."
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