I've speculated, in The Blind Watchmaker and elsewhere, that bats may 'see' colour with their ears. The world-model that a bat needs, in order to navigate through three dimensions catching insects, must surely be similar to the model that a swallow needs in order to perform much the same task. The fact that the bat uses echoes to update the variables in its model, while the swallow uses light, is incidental. Bats, I suggest, use perceived hues such as 'red' and 'blue' as internal labels for some useful aspect of echoes, perhaps the acoustic texture of surfaces; just as swallows use the same perceived hues to label long and short wavelengths of light. The point is that the nature of the model is governed by how it is to be used rather than by the sensory modality involved. The lesson of the bats is this. The general form of the mind model — as opposed to the variables that are constantly being inputted by sensory nerves — is an adaptation to the animal's way of life, no less than its wings, legs and tail are.
J. B. S. Haldane, in the article on 'possible worlds' that I quoted above, had something relevant to say about animals whose world is dominated by smell. He noted that dogs can distinguish two very similar volatile fatty acids — caprylic acid and caproic acid — each diluted to one part in a million. The only difference is that caprylic acid's main molecular chain is two carbon atoms longer than the main chain of caproic acid. A dog, Haldane guesses, would probably be able to place the acids 'in the order of their molecular weights by their smells, just as a man could place a number of piano wires in the order of their lengths by means of their notes'.
There is another fatty acid, capric acid, which is just like the other two except that it has yet two more carbon atoms in its main chain. A dog that had never met capric acid would perhaps have no more trouble imagining its smell than we would have trouble imagining a trumpet playing one note higher than we have heard a trumpet play before. It seems to me entirely reasonable to guess that a dog, or a rhinoceros, might treat mixtures of smells as harmonious chords. Perhaps there are discords. Probably not melodies, for melodies are built up of notes that start or stop abruptly with accurate timing, unlike smells. Or perhaps dogs and rhinos smell in colour. The argument would be the same as for the bats.
Once again, the perceptions that we call colours are tools used by our brains to label important distinctions in the outside world. Perceived hues — what philosophers call qualia — have no intrinsic connection with lights of particular wavelengths. They are internal labels that are available to the brain, when it constructs its model of external reality, to make distinctions that are especially salient to the animal concerned. In our case, or that of a bird, that means light of different wavelengths. In a bat's case, I have speculated, it might be surfaces of different echoic properties or textures, perhaps red for shiny, blue for velvety, green for abrasive. And in a dog's or a rhino's case, why should it not be smells? The power to imagine the alien world of a bat or a rhino, a pond skater or a mole, a bacterium or a bark beetle, is one of the privileges science grants us when it tugs at the black cloth of our burka and shows us the wider range of what is out there for our delight.
The metaphor of Middle World — of the intermediate range of phenomena that the narrow slit in our burka permits us to see — applies to yet other scales or 'spectrums'. We can construct a scale of improbabilities, with a similarly narrow window through which our intuition and imagination are capable of going. At one extreme of the spectrum of improbabilities are those would-be events that we call impossible. Miracles are events that are extremely improbable. A statue of a madonna could wave its hand at us. The atoms that make up its crystalline structure are all vibrating back and forth. Because there are so many of them, and because there is no agreed preference in their direction of motion, the hand, as we see it in Middle World, stays rock steady. But the jiggling atoms in the hand could all just happen to move in the same direction at the same time. And again. And again… In this case the hand would move, and we'd see it waving at us. It could happen, but the odds against are so great that, if you had set out writing the number at the origin of the universe, you still would not have written enough zeroes to this day. The power to calculate such odds — the power to quantify the near-impossible rather than just throw up our hands in despair — is another example of the liberating benefactions of science to the human spirit.
Evolution in Middle World has ill equipped us to handle very improbable events. But in the vastness of astronomical space, or geological time, events that seem impossible in Middle World turn out to be inevitable. Science flings open the narrow window through which we are accustomed to viewing the spectrum of possibilities. We are liberated by calculation and reason to visit regions of possibility that had once seemed out of bounds or inhabited by dragons. We have already made use of this widening of the window in Chapter 4, where we considered the improbability of the origin of life and how even a near-impossible chemical event must come to pass given enough planet years to play with; and where we considered the spectrum of possible universes, each with its own set of laws and constants, and the anthropic necessity of finding ourselves in one of the minority of friendly places.
How should we interpret Haldane's 'queerer than we can suppose'? Queerer than can, in principle, be supposed? Or just queerer than we can suppose, given the limitation of our brains' evolutionary apprenticeship in Middle World? Could we, by training and practice, emancipate ourselves from Middle World, tear off our black burka, and achieve some sort of intuitive — as well as just mathematical — understanding of the very small, the very large, and the very fast? I genuinely don't know the answer, but I am thrilled to be alive at a time when humanity is pushing against the limits of understanding. Even better, we may eventually discover that there are no limits.
Appendix
A partial list of friendly addresses, for individuals needing support in escaping from religion I intend to keep an updated version of this list on the website of the Richard Dawkins Foundation for Reason and Science: www.richarddawkins.net. I apologize for limiting the list below largely to the English-speaking world.
USA
American Atheists
PO Box 5733, Parsippany, NJ 07054-6733 Voicemail: 1-908-276-7300 Fax: 1-908-276-7402 Email: info@atheists.org
American Humanist Association
1777 T Street, NW, Washington, DC 20009-7125
Telephone: (202) 238-9088
Toll-free: 1-800-837-3792
Fax: (202) 238-9003
Atheist Alliance International
PO Box 26867, Los Angeles, CA 90026
Toll-free: 1-866-HERETIC
Email: info@atheistalliance.org
The Brights
PO Box 163418, Sacramento, CA 95816 USA Email: the-brights@the-brights.net
Center For Inquiry Transnational Council for Secular Humanism Campus Freethought Alliance Center for Inquiry — On Campus African Americans for Humanism