In Darwin’s dangerous Idea: Evolution and the Meanings of Life, Daniel Dennett describes Darwin’s idea as the “best idea anyone has ever had.”

In a single stroke, the idea of evolution by natural selection unifies the realm of life, meaning, and purpose with the realm of space and time, cause and effect, mechanism and a physical law. But it is not just a wonderful scientific idea. It is a dangerous idea.

What exactly was Darwin’s dangerous idea? According to Dennett, it was “not the idea of evolution, but the idea of evolution by natural selection, an idea he himself could never formulate with sufficient rigor and detail to prove, though he presented a brilliant case for it.” (42)  Dennett considers Darwin’s idea to be “dangerous” because it has so many fruitful applications in so many fields above and beyond biology. When Dennett was a schoolboy, he and some of his friends imagined that there was such a thing as “universal acid,”

a liquid “so corrosive that it will eat through anything! The problem is: what do you keep it in? It dissolves glass bottles and stainless steel canisters as readily as paper bags. What would happen if you somehow came upon or created a dollop of universal acid? With the whole planet eventually be destroyed? What would it leave in its wake? After everything had been transformed by its encounter with universal acid, what would the world look like? Little did I realize that in a few years I would encounter an idea-Darwin’s idea-bearing an unmistakable likeness to universal acid: eats through just about every traditional concept, and leaves in its wake a revolutionized world-view, with most of the old landmarks are still recognizable, but transformed in fundamental ways.

(63) Darwin’s idea is powerful, indeed. Many people see it as having the power to ruin the meaning of life.

People fear that once this universal acid has passed through the monuments we cherish, they will cease to exist, dissolved in an unrecognizable and unlovable puddle of scientific destruction.

Dennett characterizes this fear is unwarranted:

We might learn some surprising or even shocking things about these treasures, but unless our valuing these things was based all long on confusion or mistaken identity, how could increase understanding of them diminish their value in our eyes? (82)

It appears that Dennett’s vision is well substantiated because natural selection is “universal acid.” How so?  Its application goes far  beyond the immense field of evolutionary biology.  For a good summary, consider “The Ascent of Darwin,” written by Karen Wright  appearing in the March, 2009 edition of Discover Magazine.

In the 150 years since the publication of on the origin of species, it seems no sphere of human thought or activity has been left untouched by Darwinian analysis. Evolutionary theory has infiltrated the social sciences, where it has been used to explain human politics and spending habits. It has transformed computer science, inspiring problem-solving algorithms that adapt and change like living things. It is cited by a leading theoretical physicist who proposes that evolution helps to shape the laws governing the cosmos. A renowned neuroscientist sees ideas of selection as describing the honing of connections among brain cells. Literary critics analyze the plots, themes and characters of novels according to Darwinian precepts. Even religion, the sector most famously at odds with Darwin, now claims an evolutionary evangelist.

Wright recognizes natural selection as creating “a dynamic, ever-changing biota,” and she has compiled an impressive list of modern-day applications of natural selection.

For instance natural selection has been used to describe the rise of complexity in inanimate systems such as stock markets and transit schedules. “Only Darwin’s approach shows how certain complex systems not only arise but also adapt over time to the constraints imposed by their environment, as living systems do.”

Lee Smolin has developed a theory positing the existence of a vast number of unseen universes, a multi-verse, resulting in the present universe with its “improbable complexity.”  Another application is the computer programming technique employing genetic algorithms, which allows solutions to problems that resist traditional analyses. In one application, a genetic algorithm was used to further the design of a jet engine for Boeing. Wright describes the work of John Holland, professor of psychology and computer science, who has been using genetic algorithms to simulate complex adaptive systems.

Physician Gerald Edelman has made use of evolutionary theory to explain the manner in which the body generates a virtually infinite variety of antibodies to counter pathogens. Wright notes that Edelman has also applied natural selection to explain the method by which the brain wires itself, arguing that “memories are created when interactions with the environment preferentially strengthened the connections between certain populations of neurons.”

Psychiatrist Randolph Nesse is a pioneer in the field of Darwinian medicine, urging that physicians need to take into account the evolutionary history of the human animal when diagnosing their patients conditions. “Without an evolutionary background, you really can’t get a grasp on why the body isn’t designed better.” For more on Nesse, consider this conversation between Nesse and Richard Dawkins.

Evolutionary theory has also been applied to explain cooperative behavior based on “so-called group selection, which holds that traits can persist or spread in a population even though they can be costly to the individual if they bestow an advantage on the group.”  Proponents of group selection theory include David Sloan Wilson and Edward O. Wilson.

Wright admits, however, that there are “conspicuous holdouts” to Darwin’s ideas: artists and religious believers. Geoffrey Miller has eloquently offered a Darwinian explanations for art and other forms of human creativity, making liberal use of Darwin’s theory of sexual selection (“Art evolved as a way for potential mates to show off their intellectual fitness”).  Miller and Gad Saad have applied evolutionary framework to many other aspects of human life, including consumer extravagances.   With regard to religion, evangelist Michael Dowd has embraced natural selection, teaching that “evolution gives us a more intimate and personal relationship with God because God is no longer far off, unnatural, and impotent.”  Decades earlier, I was taught in Catholic high school about the teachings of Jesuit priest and paleontologist Teilhard de Chardin, who “envisioned humankind and the universe evolving in the direction of a divine, infinitely complex consciousness he calls the Omega Point.

Wright’s list includes Helen Fisher’s application of evolutionary psychology to an online dating service.  Certainly, if bodies can evolve, why not behaviors? Evolutionary psychology attempts to take on questions such as “what is love?” And “why do we vote the way we do?”

Although many people have been critical of the “just so stories” of some evolutionary psychologists, anyone who takes the time to review the experimental results of David Buss (as one example) will see that it is absolutely unfair to paint the entire field as merely “just so stories.”

What other kinds of questions do evolutionary psychologists address? Such things as the short-term and long-term mating strategies of men versus women, the consequences of paternity uncertainty, parent-offspring conflict, mate guarding, cooperation among humans as well as warfare, and manifestations of evolutionary theories of dominance, prestige and status. Many of the critics of evolutionary psychology would prefer that these questions not be addressed when it comes to human animals, or that they be addressed without any coherent scientific framework. It seems, though, that these are unwieldy yet compelling questions that demand some framework rather than none, and Darwin’s dangerous theory has yielded some impressive answers with a promise for many more worthwhile explorations to come.

Daniel Dennett’s idea of Darwinian universal acid is therefore well-substantiated; natural selection provides a central organizing framework for a rapidly growing number of aspects of life, including human “social” life. So much so that it makes Theodosius Dobzhansky’s claim seem understated: “Nothing in biology makes sense except in the light of evolution.”

In the conclusion to his Origin of Species, Darwin himself envisioned broad application for his dangerous theory.

In the future I see open fields for far more important researches. Psychology will be securely based on the foundation already well laid a Mr. Herbert Spencer, that of the necessary requirement of each mental power and capacity by gradation. Much light will be thrown on the origin of man and his history.