Consilience

Physical sciences are difficult, but even harder and more complex are the social sciences and the humanities. The challenge is to bring them into the realm of logic, evidence, and proof. The story of Theseus and the minotaur serve as a symbol of this quest. Theseus ties one end of a ball of yarn to a rock and unreels the ball as he descends in to the minotaur’s labyrinth. Theseus locates the minotaur and slays it in battle, then finds his way back along the string. The labyrinth represents the material world; the string is the consilience of connections between the branches of knowledge: “Theseus is humanity, the Minotaur our own dangerous irrationality" (73). The upper galleries are the physical sciences, and within the deep interior lie the mazes of the social sciences, the humanities, and religion whose branching possibilities dwarf the physical sciences in complexity.

Similarly, researchers can travel into the depths of cell biology, along the way learning the details of the organelles and molecules that make up various cells, but they are unable to use that knowledge to predict how organelles will be organized in a different type of cell nearby; they get lost trying. In the 1950s, Wilson studied how harvester ants communicate by first reasoning that the ants must use odors to send signals in the dark, then extracting organs from ants and crushing them to release any odors, and waving them at the harvester workers in an ant farm until two of the organs generated strong reactions in the ants, who swarm toward the odor expecting to fight an incoming enemy. An associate analyzed the odors and discovered that they are known types of pheromones. He and Wilson thereby discovered a chief means of ant communication.

Having descended from ant colony to chemical molecules, Wilson wondered whether it would be possible to make predictions from chemistry to animal behavior. They reason that alarm pheromones will be smaller than food pheromones—emergencies pass quickly, but food sources need a chemical signal that’s heavy and will stick around—and this turns out to be true. It did not prove possible, however, to predict which pheromones would do the various jobs, or from which glands. This demonstrates the difficulty of making complex assumptions from simple discoveries; much more information is needed about the ants, their histories, and their environments before such a predictive synthesis might be possible.

Shamans of the Amazon region ingest neuromodulator drugs, such as Datura and ayahuasca, to induce dreamlike trances where they encounter otherworldly spirits, many in the shape of serpents. Because poisonous snakes can be deadly, primates, including humans, inherit a natural tendency to fear them, a fear that often grows stronger during adolescence; many cultures have snakes as gods or symbols of power. Scientific study of these dreams might provide insight on the inner workings of the deep mind. Sigmund Freud proposed that dreams permit the airing of repressed desires in the form of symbolic stories. A more recent theory, the activation-synthesis model, posits that dreams are simply a phantasmagoric by-product of the brain’s processing of memories formed during the day. Perhaps the true meaning of dreams, if there is one, lies somewhere between these two theories.

The biological sciences approach questions about organisms from different perspectives of space and time. The grandest view is evolutionary biology, which looks at centuries and vast portions of the Earth’s surface; ecology studies regions over years and decades; organismic biology observes single lifetimes in discrete locations; cellular biology focuses in on fractions of seconds and millimeters; and molecular biology and biochemistry study the microscopic and subatomic. Together, these various scales make up the totality of biology as it is studied and taught, creating a consistent and consilient system of thought.

While the complexities of organisms can be whittled down to the cellular and molecular level, going the other way—to infer, from atoms, the shape of proteins, their assembly into organelles, organelles into cells, cells into tissues, and so forth—is difficult. The subtle energy relationships between nearby atoms, for example, plus the even more subtle effects from more distant atoms, make such calculations enormous. It gets worse when studying ecology, where, at best, scientists can study the interactions of a few organisms at a time, and complexities of their interactions with the rest of the hundreds or more species nearby increase exponentially to become, in practice, unmeasurable. The simple removal of top predators from a local area, for example, will cause a cascade of surprising and unpredictable effects within that environment.

Since the 1970s, a new approach, complexity theory, searches for the algorithms nature uses to generate complex systems from simple building blocks. Whether any such rules of nature exist is hotly debated. Already, chaos theory and fractal geometry have proven instructive, for instance helping biologists discover rhythmic patterns in population growth and decline. Another approach is Stuart Kauffman’s NK model, which states that an organism must be unstable enough in design to adapt easily to changing environments but not so unstable as to collapse into chaos.

However, no model yet has triggered an outpouring of new theories within biology. Furthermore, biologists “foresee no need for overarching grand explanations as a prerequisite for creating artificial life" (99). Already they know that DNA translates to RNA and thence to amino acids which self-assemble into the complex proteins that form half of the body’s mass, and that some proteins, the enzymes, behave like microscopic factories, shaping and altering other molecules—splitting sucrose into glucose and fructose, for example—to turn them into useful products.

From the knowledge so far acquired, biologists believe that they will soon be able to assemble an entire synthetic cell. Beyond that, they hope to construct tissues and then organ systems, including nervous systems, and thereby begin to understand in detail the biochemical underpinnings of the mind and behavior. The question remains whether biologists will arrive at general principles “that allow a living organism to be reconstituted in full without recourse to brute force simulation of all its molecules and atoms" (103). With the rapid advance of computers and massive digital simulations, those discoveries may await scientists in the near future.