Consilience, or the unity of knowledge (literally a "jumping together" of knowledge), has its roots in the ancient Greek concept of an intrinsic orderliness that governs our cosmos, inherently comprehensible by logical process, a vision at odds with mystical views in many cultures that surrounded the Hellenes. The rational view was recovered during the high Middle Ages, separated from theology during the Renaissance and found its apogee in the Age of Enlightenment. Then, with the rise of the modern sciences, the sense of unity gradually was lost in the increasing fragmentation and specialization of knowledge in the last two centuries. The converse of consilience in this way is Reductionism.
The word consilience was apparently coined by William Whewell, in The Philosophy of the Inductive Sciences, 1840. In this synthesis, Whewell explained that "The Consilience of Inductions takes place when an Induction, obtained from one class of facts, coincides with an Induction obtained from another different class. Thus Consilience is a test of the truth of the Theory in which it occurs." The Scientific method has become almost universally accepted as the exclusive method for testing the status of any scientific hypothesis or theory. "Inductions" that arise out of applications of the scientific method are, by definition, the only accepted indicators of consilience.
Modern views understand that each branch of knowledge studies a subset of reality that depends on factors studied in other branches. Atomic physics underlies the workings of chemistry, which studies emergent properties that in turn are the basis of biology. Psychology can no longer be separated from the study of properties emergent from the interaction of neurons and synapses. Sociology, economics, and anthropology are each, in turn, studies of properties emergent from the interaction of countless individual humans. Their limits have constrained history.
Edward O. Wilson
The word had remained shelved until the end of the 20th century, when it was vividly revived in Consilience: The Unity of Knowledge, a 1998 book by the humanist biologist Edward Osborne Wilson, as an attempt to bridge the culture gap between the sciences and the humanities that was the subject of C. P. Snow's The Two Cultures and the Scientific Revolution, 1959. Wilson's assertion was that the sciences, humanities, and arts have a common goal: to give a purpose to understand the details, to lend to all inquirers "a conviction, far deeper than a mere working proposition, that the world is orderly and can be explained by a small number of natural laws." This is the essence of consilience. And in this way, consilience is very similar to reductionism.
A parallel view lies in the term universology, which literally means "the science of the universe." Universology was first advocated for the study of the interconnecting principles and truths of all domains of knowledge by Stephen Pearl Andrews, a 19th-century utopian futurist and anarchist.
- "To ask if consilience can be gained in the innermost domains of the circles, such that sound judgment will flow easily from one discipline to another, is equivalent to asking whether, in the gathering of disciplines, specialists can ever reach agreement on a common body of abstract principles and evidentiary proof. I think they can. Trust in consilience is the foundation of the natural sciences. For the material world at least, the momentum is overwhelmingly toward conceptual unity. Disciplinary boundaries within the natural sciences are disappearing, to be replaced by shifting hybrid domains in which consilience is implicit. These domains reach across many levels of complexity, from chemical physics and physical chemistry to molecular genetics, chemical ecology, and ecological genetics. None of the new specialities is considered more than a focus of research. Each is an industry of fresh ideas and advancing technology. Given that human action comprises events of physical causation, why should the social sciences and humanities be impervious to consilience with the natural sciences? And how can they fail to benefit from that alliance? It is not enough to say that human action is historical, and that history is an unfolding of unique events. Nothing fundamental separates the course of human history from the course of physical history, whether in the stars or organic diversity. Astronomy, geology, and evolutionary biology are examples of primarily historical disciplines linked by consilience to the rest of the natural sciences."
- "Every college student should be able to answer the following question: What is the relation between science and the humanities, and how is it important for human welfare? Every public intellectual and political leader should be able to answer that as well. Already half the legislation coming before the United States Congress contains important scientific and technological components. Most of the issues that vex humanity daily - ethnic conflict, arms escalation, overpopulation, abortion, environment, endemic poverty, to cite several most consistently before us - cannot be solved without integrating knowledge from the natural sciences with that of the social sciences and humanities. Only fluency across the boundaries will provide a clear view of the world as it really is, not as seen through the lens of ideologies and religious dogmas or commanded by myopic response to immediate need. Yet the vast majority of our political leaders are trained exclusively in the social sciences and humanities, and have little or no knowledge of the natural sciences. The same is true for the public intellectuals, the columnists, the media interrogators, and think-tank gurus. The best of their analyses are careful and responsible, and sometimes correct, but the substantive base of their wisdom is fragmented and lopsided."
- "The mind is not like a wax tablet. On a tablet you cannot write the new till you rub out the old; on the mind you cannot rub out the old except by writing in the new. Beware of the idols of the mind, the fallacies into which undisciplined thinkers most easily fall. They are the real distorting prisms of human nature. Among them, idols of the tribe assume more order than exists in chaotic nature; those of the imprisoning cave, the idiosyncrasies of individual belief and passion; of the market place, the power of mere words to induce belief in non-existent things; and of the theater, unquestioning acceptance of philosophical beliefs and misleading demonstration. Stay clear of these idols, observe the world around you as it truly is, and reflect on the best means of transmitting reality as you have experienced it; put into it every fiber of your being."
- "Outside our heads there is freestanding reality. Only madmen and a scattering of constructivist philosophers doubts its existence. Inside our heads is a reconstitution of reality based on sensory input and the self-assembly of concepts. Input and self-asembly, rather than an independent entity in the brain - the "ghost in the machine," in the philosopher Gilbert Ryle's famous derogation - constitute the mind. The alignment of outer existence with its inner representation has been distorted by the idiosyncrasies of human evolution, as I noted earlier. That is, natural selection built the brain to survive in the world and only incidentally to understand it at a depth greater than is needed to survive. The proper task of scientists is to diagnose and correct the misalignment. The effort to do so has only begun. No one should suppose that objective truth is impossible to attain, even when the most committed philosophers urge us to acknowledge that incapacity. In particularly it is too early for scientists, the foot soldiers of epistemology, to yield ground so vital to their mission."
- "On the surface it would seem, and was so reported by the media, that the Rwandan catastrophe was ethnic rivalry run amok. That is true only in part. There was a deeper cause, rooted in environment and demography. Between 1950 and 1994 the population of Rwanda, favored by better health care and temporarily improved food supply, more than tripled, from 2.5 million to 8.5 million. In 1992 the country had the highest growth rate in the world, an average of 8 children for woman. Parturition began early, and generation times were short. But although total food production increased dramatically during this period, it was soon overbalanced by population growth. The average farm size dwindled, as plots were divided from one generation to the next. Per capita grain production fell by half from 1960 to the early 1990s. Water was so overdrawn that hydrologists declared Rwanda one of the world's twenty-seven water-scarce countries. The teenage soldiers of the Hutu and Tutsi then set out to solve the population problem in the most direct possible way. Rwanda is a microcosm of the world. War and civil strife have many causes, most not related directly to environmental stress. But in general, overpopulation and the consequent dwindling of available resources are tinder that people pile up around themselves. The mounting anxiety and hardship are translated into enmity, and enmity into moral aggression. Scapegoats are identified, sometimes other political or ethnic groups, sometimes neighboring tribes. The tinder continues to grow, awaiting the odd assassination, territorial incursion, atrocity, or other provocative incident to set it off. Rwanda is the most populated country in Africa. Burundi, its war torn neighbor, is second. Haiti and El Salvador, two of the chronically most troubled nations of the Western Hemisphere, are also among the most densely populated, exceeded only by five tiny island countries of the Caribbean. They are also arguable the most environmentally degraded."
- "If the natural sciences can be successfully united with the social sciences and humanities, the liberal arts in higher education will be revitalized. Even the attempt to accomplish that much is a worthwhile goal. Profession-bent students should be helped to understand that in the twenty-first century the world will not be run by those possess mere information alone. Thanks to science and technology, access to factual knowledge of all kinds is rising exponentially while dropping in unit cost. It is destined to become global and democratic. Soon it will be available everywhere on television and computer screens. What then? The answer is clear: synthesis. We are drowning in information, while starving for wisdom. The world henceforth will be run by synthesizers, people able to put together the right information at the right time, think critically about it, and make important choices wisely."
- "The smart money in eschatology is on Blaise Pascal's wager: Live well but accept the faith. If there is an afterlife, the seventeen-century French philosopher reasoned, the believer has a ticket to paradise and the best of both worlds, "If I lost," Pascal wrote, "I would have lost little; if I won I would have gained eternal life." Now think like an empiricist for a moment. Consider the wisdom of turning the wager around as follows: If fear and hope and reason dictate that you must accept the faith, do so, but treat this world as if there is none other."
- The complementary instincts of morality and tribalism are easily manipulated. Civilization has made them more so. Only ten thousand years ago, a tick in geological time, when the agricultural revolution began the Middle East, in China, and in Mesoamerica, populations increased in density tenfold over those of hunter-gatherer societies. Families settled on small plots of land, villages proliferated, and labor was finely divided as a growing minority of the populace specialized as craftsmen, traders, and soldiers. The rising agricultural societies, egalitarian at first, became hierarchical. As chiefdoms and then states thrived on agricultural surpluses, hereditary rulers and priestly castes took power. The old ethical codes were transformed into coercive regulations, always to the advantage to the ruling classes. About this time the idea of law-giving gods originated. Their commands lent the ethical codes overpowering authority, once again - no surprise - to the favor of the rulers."