Bones of Contention: Controversies in the Search for Human Origins by Roger Lewin (Simon & Schuster: $19.95; 348 pages, illustrated)
Early on in this fascinating account of the effort to reconstruct the evolution of mankind from the fossil record, Roger Lewin gives us this insight:
"We do not see things the way they are;
"We see them the way we are."
At first he attributes these words of wisdom to the Talmud, which seems plausible. Then he discovers that the source was actually a Chinese fortune cookie.
In some ways, this revised explanation is a metaphor for the entire science of paleoanthropology, the subject of this book. Lewin describes it as "short on data and long on opinion." As a result, it is subject to constant revision as researchers interpret and reinterpret a handful of fossils, filling in the gaps by guessing at explanations and making up stories.
Lewin, a trained scientist who is an editor at Science magazine, has written a marvelous account of what is known (not very much) and what is not known (a lot) about how human beings evolved.
A Portrait of Science
But his book is more than that. It is an account of how science itself is done, and the portrait is nothing like the cool, dispassionate, objective model that philosophers of science would have us believe. In Lewin's telling, the development of this science--and, one surmises, many sciences--is ruled by personality as much as by facts.
In support of this view, he quotes David Pilbeam, a British anthropologist, who wrote, "I have come to believe that many statements we make about the hows and whys of human evolution say as much about us, the paleoanthropologists, and the larger society in which we live, as about anything that 'really' happened."
This view of the relativity of all statements about the world is certainly in keeping with current thought, which holds that in the end, truth is nothing more nor less than what everybody agrees is true.
The more one explores the scientific method and its philosophical foundations, the more one discovers its inherent circularity. The validity of the method cannot itself be proved. It has to be assumed.
In his book, "What Is This Thing Called Science?" the British philosopher of science Alan Chalmers put it bluntly: "There is no timeless and universal conception of science or scientific method," he wrote.
Carried to its conclusion, this view holds that science is just one more ideology in a world brimming with ideologies. While "Bones of Contention" does not explicitly make that argument, it comes very close. (The book, after all, is about bones, not about philosophy, though its philosophical underpinnings are at least as interesting as its avowed subject matter.)
Now, this debate is as old as philosophy itself. Is there a world out there that contains a truth independent of the knower? If so, can we know it? And if we can, how should we go about knowing it?
Or, on the other hand, is the order that we observe in the world simply imposed by us? If that is the case, what status, if any, does truth have? Is it just a chimera, one more way in which we fool ourselves about reality?
I certainly don't know the answers to these questions, but I take comfort in knowing that no one else does either. The current vogue is to define truth by placing great emphasis on the role of knower. I find such statements too weak. There is a reality out there that does not bend to our whims.
But assertions about truth that emphasize the primacy of that reality I find too strong. We are not merely passive observers of the universe. Our knowing helps to shape it.
In the 5th Century BC, the Greek philosopher Gorgias said, "One can persuade anyone of anything if one speaks well enough." To which Aristotle replied, "One is more likely to win one's argument if what one says is true."
Interpreting the Evidence
This discussion may seem like a digression from the book at hand, but it is inextricably connected with it. In the end, "Bones of Contention" is about how we know what we know. What constitutes evidence, and how do we fill in the gaps where the evidence is scanty, nonexistent or inconclusive?
Lewin has done a superb job in bringing to life the personalities in the search for the origins of humanity--the Leakeys and Donald Johanson foremost among them--and he gives a vivid account of the ways in which field work is done and theories are created and defended.
As a reporter, he has the ability to get his subjects to speak openly and frankly and to give voice to their doubts as well as to their certainties. The result is a portrayal of science as it is really done, warts and all. Far from detracting from the material, this approach adds to it.
The search for the origins of man is one of science's most thrilling and bedeviling endeavors. Readers of this book will learn much about what is known and what is unknown and about the people who are trying to find out.
They will also be left to wonder about how we know anything anyway.