CONSILIENCE.

"Consilience of inductions" is a phrase that was invented by the nineteenth-century English historian and philosopher of science William Whewell (1794–1866; pronounced "Hule"), and introduced in his Philosophy of the Inductive Sciences (1840). Whewell was trying to capture the notion of what Isaac Newton (1642–1727) had labeled a "true cause," or vera causa, the kind of cause that supposedly lies at the center of the very best kinds of scientific theories. Whewell's friend, the astronomer and philosopher John F. W. Herschel (1792–1871), had argued (in an empiricist fashion) that a true cause is something that we ourselves experience directly or analogically. We know for instance that a force is pulling the moon toward the earth, because we have had direct experience of the tug of a string as we are whirling around with a stone tied to its end.

Whewell, to the contrary, in a rationalist fashion, wanted to characterize a true cause as something that is not necessarily experienced at all, but that is adequate to explain the empirical facts as we know them. He argued therefore that such a cause must be at the center of a scientific explanation, explaining all of the disparate facts and in turn being explained by them. If such a cause can predict and explain new and excitingly unexpected facts, then so much the better. Such a fan-like construction, with the cause at the apex, Whewell labeled a consilience of inductions. He argued also that such a situation is as simple as it is possible for a theory to be, and hence a true cause is also marked by the fact that it is the most economical of explanatory forces, with many parts being reduced to one fundamental mechanism.

For Whewell and Herschel, the paradigmatic example of a true cause was Newtonian mechanics, which used the one force—gravitational attraction—to explain not just the heavenly motions of the planets but also the earth-bound motions of such things as cannonballs. Johannes Kepler's (1571–1630) laws of celestial motion and Galileo Galilei's (1564–1642) laws of terrestrial motion were brought beneath one force. But Whewell and Herschel themselves were arguing over the science of their day, most particularly the nature and causes of light. The beginning of the nineteenth century was the time when the wave theory of Christiaan Huygens (1629–1695) was conquering the particle theory of Isaac Newton. The problem is that no one sees waves. Herschel argued that we have experienced analogous phenomena to light waves, for instance the waves of water in a pond. Hence it is reasonable to suppose that light waves produce such things as interference patterns. Whewell replied that there is no need of analogies—it is enough that the wave theory explains many phenomena that are impossible to explain with the particle theory. The patterns produced by something such as Thomas Young's (1773–1829) double-slit experiment are themselves enough to confirm that light travels in waves and not in particles.

Also dividing Whewell and Herschel was the true nature of geology, with Whewell arguing that it is permissible—even obligatory—to invoke unseen upheavals (catastrophes), and with Herschel agreeing with the uniformitarian geologist Charles Lyell (1797–1875) that unlimited time is enough to produce all changes, given the kinds of causes (rain, sleet, earthquakes, and so forth) that we see around us today. A young scientist who took deep note of Whewell's arguments was Charles Darwin (1809–1882), who, realizing that no one can ever see evolution actually occurring, consciously modeled his Origin of Species (1859) on Whewell's thinking. Having introduced his mechanism of natural selection, Darwin then spent the rest of the work showing how selection explains so many different areas—instinct, biogeography, paleontology, embryology, morphology, classification, and more—and how these areas in turn confirm natural selection as a true cause. When challenged, Darwin always referred to this strategy, even though, somewhat paradoxically, Whewell himself never became an evolutionist and supposedly would not allow the book on the shelves of the Cambridge college of which he was principal.

Consilience in Modern Science

The consilience of inductions figures high in modern science. Its broad explanatory power was the main reason that so many geologists were so quickly converted to the theory of plate tectonics. Supposing that the continents move explains so much—the shape of the continents, the position of earthquakes and volcanoes, the trenches in the middle of oceans, the magnetic lines, and much more. In recent years the idea has been extended into philosophy and to thinking about science and knowledge generally. The Harvard student of the ants and of social behavior (sociobiology), Edward O. Wilson, argues that all of human knowledge is heading toward a consilience—a consilience where evolution will be the all-powerful joining and explaining idea. We have a kind of gene-culture coevolution, where culture tries to impose its ways and norms on human behavior and thought, but where the genes always constrain the flights of fancy and make sure that human nature never strays too far from the basic biological.

Wilson argues that morality for instance cannot exist as a disembodied ethereal enterprise, but must be rooted firmly in our evolutionary background—morality exists because and only because it was and is of use to us as creatures struggling to survive and reproduce. Those humans who worked together did better than those who did not. Likewise, religion serves to bind humans together in well-functioning units. It has no correspondence to reality but serves as an adaptation toward the greater success of Homo sapiens. Wilson argues that we must strive to achieve ever-greater consiliences between disparate parts of human knowledge until all is bound together in one big super-picture. Only then will we humans recognize the extent to which we are part of this big picture—a picture that includes all of natural diversity. Only then will we humans be truly motivated to the preservation of the living world around us, something from which we emerged and something without which we can never hope to survive. Consilience has therefore moved from the epistemological norm of William Whewell to the moral imperative of Edward O. Wilson.

See also Causation ; Science, Philosophy of .

bibliography

Ruse, Michael. The Darwinian Revolution: Science Red in Tooth and Claw. 2nd ed. Chicago: University of Chicago Press, 1999. Originally published in 1979.

Whewell, William The Philosophy of the Inductive Sciences. 2 vols. London: Parker, 1840.

Wilson, Edward O. Consilience. New York: Knopf, 1998.

Michael Ruse