Features: Interviews

Skeptic: In your latest book, River Out of Eden, which is a best seller in the UK, you use deep-sea bacteria that metabolize sulfur (rather than oxygen) to illustrate how evolution takes place in a series of successive steps. Does the existence here on Earth of an alternative metabolic "fuel", in some sense make it more probable that there could be life elsewhere in the universe, perhaps using a different base than carbon?

Dawkins: That's surely got to be right, hasn't it? You can speculate in a science fiction way about alternative biochemistries for life, but if you couldn't find anything on Earth moving ever so slightly towards an alternative biochemistry, that would argue against the idea. But when you do find an alternative biochemistry for life here on Earth, that makes it more plausible that somewhere else in the universe there's got to be an alternative form of life.

Skeptic: What then is the sine qua non of life? What raw materials and conditions are necessary for life to exist?

Dawkins: Well, you need raw materials that can self-replicate. I would have to be more of a chemist than I am to know how likely it is that you are going to get such molecules. I should very much like to direct chemists toward devising an alternative hypothetical chemistry that supports self-replication, a whole alternative system that could, in principle, give rise to life. The fundamental principle that will be required is self-replication. Chemists have begun to look at auto-catalytic functions in chemistry where at least some of the prerequisites are present. The sine qua non, as you say, is self-replication. I don't know how difficult it would be to achieve that chemically.

Skeptic: How likely do you think it is that "intelligent" life exists somewhere else in the universe?

Dawkins: At first glance, one might think that the really difficult step is getting life at all. Then once natural selection has gotten going (since the origin of life is really the origin of natural selection), you can proceed by an orderly progressive sequence through the evolution of some kind of information processing apparatus on to intelligence. On the other hand, if you look at what's actually happened on this planet, it probably took less than a billion years from the origin of the planet, under fairly unfavorable initial conditions, to produce life. But intelligence of a high order has only come about in the last couple of million years, perhaps. So it does seem that on this planet at least there has been a rather short interval from the origin of the planet to the origin of life and then a very, very long interval between the origin of life and the origin of intelligence.

Skeptic: Are you then saying that the origin of intelligence is the bigger step?

Dawkins: It's not my inclination to say that, but this disparity in time scale is the only data we have. We only have one sample – life on this planet. But for that fact, my personal inclination would have been to suggest that the origin of intelligence is not that difficult once you've got life. I'm quite intrigued by the thought that maybe it's the origin of life that's not that difficult.

Skeptic: If so, what are the defining qualities of such "intelligence?" I'm thinking here of concepts such as Immanuel Kant's list of apriori ideas – time and space, number, cause and effect. Could, for example, a form of life evolve in whose mental map time's arrow went backwards, or in no specific direction?

Dawkins: As for what one means by intelligence, I haven't really thought about that. You posed the hypothetical question, "Could there be a life form whose concept of time goes backward?" I can't imagine what that would look like. But I haven't thought about it enough.

Skeptic: Of other species we know about here on Earth, we're very familiar with cats and dogs. I was always amazed (and delighted) how my dogs could coexist with me given that their set of sensory inputs was so different from mine – they see in black and white, not in 3D; they use scent and vision in approximately opposite proportions. Yet they can come up with an equivalent map of the world so that they can fetch the paper, protect us from intruders, comfort us in distress. What does this tell us about the evolutionary process and how it molds not only the bodies but the cognitive maps of different species?

Dawkins: That's an intriguing point. One thing you could say about dogs is that they have been domesticated, and a good deal of the domestication has been an inadvertent selection for coexisting with humans. While their wild ancestors, the wolves, do have facial expressions and other gestures which they use to communicate with each other, it's probable that domestic dogs have been selected to have more human feelings and facial expressions. So while dogs don't smile, they do other things with their eyes that appeal to humans. Maybe they have been shaped to be a bit less wolf-like and a bit more human-like, not by deliberate artificial selection, but by artificial selection nonetheless.

Skeptic: In the 1930s, von Uexküll used the term Umwelt to describe the different "real worlds" that animals construct based upon their differing sensory systems. He even built mechanical devices to try and create their perceptual Weltanschauungen. He manufactured optical devices to simulate the compound eyes of insects to allow one to see "what they saw." With virtual reality now a reality, we could certainly do such things at a more sophisticated level than von Uexküll did. Do you think this might be a potentially valuable line of research?

Dawkins: Von Uexküll used the concept of the Umwelt to explore the differences between the perceptual worlds of different animals. He tried to find a way to "think himself into" the Umwelt (the perceptual world) of a bee or a bat, for example, by seeing the polarization of light or by seeing into the ultraviolet range of the spectrum and thus probably not seeing images as we see images at all. I think it' s a very important thing to do that, partly as a metaphor for "getting outside yourself" and seeing another point of view. We have an immensely human-centered view of things such as ethics and morality. Even if we pay lip service to being evolutionists, many people still think according to the Judeo-Christian view that all things have been put on Earth for the benefit of humanity and that the only justification for scientific research is if it benefits humanity. I think it's a salutary lesson to try to "think yourself into" the Umwelt of another species. But as I said in my talk last night before the Human Behavior and Evolution Society, I suspect that the perceptual world of other species possibly may not be as different from our own as you might think, even though they get their information through different physical media.

Skeptic: So then doesn't natural selection force us to assume that time's arrow flies in a certain direction? Doesn't natural selection force us to operate on the basis of Kant's a priori ideas and Piaget's operations?

Dawkins: Yes, I agree with that.