Strange bedfellows?

Symposium forges alliance between philosophy and science
by C.W. Wolff

It was the last question of a long day: "Is the philosophy of science keeping up with the progress of science?"

The audience in the Sackler Center auditorium on the Boston campus leaned forward to hear the answer of a half-dozen philosopher/scientists.

Dr. Carlos Sonnenschein says that cancer has more to do with interactions between cells than with single-cell genetics. © Mark Morelli

"Scientists have not kept up with where philosophers have gone," responded Sahotra Sarkar, a geneticist and philosopher from the University of Texas at Austin, adding biomedical scientists would do well to "professionalize" themselves by deepening their understanding of the philosophical foundations and implications of their investigations.

Swarthmore College biologist Scott Gilbert noted that the amount of attention philosophers are paying to evolutionary developmental biology is "remarkableÉThey're not just in the audiences of conferences; they're at the table, helping science as it progresses."

At the table on that mid-April day, besides Sarkar and Gilbert, were Jean-Jacques Kupiec of the Hospital Cochin INSERM in France and seminar organizers Dr. Carlos Sonnenschein and Dr. Ana Soto, both professors of anatomy and cellular biology at Tufts, and Daniel C. Dennett, Fletcher Professor of Philosophy at Tufts.

Tufts President Lawrence S. Bacow opened the day-long "Sesquicentennial Symposium: The Philosophical Bases of Biological Thought" on April 16 by praising its cross-disciplinary nature and suggesting it was normative of what should be happening at a universityÑwhat he called "an increase in the permeability of cell membranes" between disciplines.

Serendipitous engineering
The limitations of reductionism in biological researchÑthe notion that biology can best and most fundamentally be understood through a linear approach from largest to smallest unitsÑwas the focus of much of the day's conversation.

The "top-down model" found in engineering is seductive, noted Dennett. But he cautioned: "The dimensions of thrift and waste are different in human engineering than they are in Mother Nature engineering."

"The fundamental question in biology is "What's the function?Éas if any one answer exists," Dennett said. "In nature, engineering is serendipitous, multi-functional, something that is rare in human engineering because of modularity of designÉBiological engineering is always building and breaking, using robustness in place of guarantees."

Sarkar also was concerned with over-simplistic reductionism. "We need to stop worrying about the gene as an agent that gives all instructions of what a cell should do," he said. "The genome is not programs, but recipes." The very fact that there are about 30,000 genes in humansÑwhile at least 100,000 proteins are producedÑchallenges the idea of gene specificity.

Aristotle and biology
"Genetic reductionism is a very powerful and efficient theory," said Kupiec. "The problem is it has implications that do not fit the facts." For instance, Kupiec said, molecules can associate in many different fashions, even though only a few of those combinations are functional. "The notion of specificity is a contribution of Aristotle, not biology," he said. "It is an idealization of matter and cannot describe molecular interactions."

Soto and Sonnenschein presented their challenges to what they saw as questionable biological assumptions on which the direction of investigations are based. They specifically question the prevailing notion that the default state of human cells is quiescence, positing instead that it is proliferation. They suggest further that partially because of genetic reductionism, scientists are hesitant to re-evaluate the theory that cancer is the result of a mutation in a single, normal cell that causes it to proliferate out of control.

"But 100 years of slashing, burning and killing cells to get rid of cancer hasn't worked," said Sonnenschein, adding that the search for specific growth factors that could be the key to carcinogenic cell proliferation also has failed. Sonnenschein and Soto advance the theory that cancer has more to do with interactions between cells and interactions within tissue than with single-cell genetics.

Beyond the organism
Gilbert expanded the scope to another level when he suggested developmental biologists tend to have too narrow a view by generally downplaying external impacts on how organisms develop and how those changes are passed along.

"We need to get out of the blinders of an organistic view and look at the natural context of an organism," he said, urging an expansion of the theory that organisms arise through a process of progressive development from simple to complex structures to include interactions with the environment.

Sonnenschein concluded the symposium with the suggestion that this is only the beginning of a dialogue "necessary and useful to both philosophers and scientists."