Nothing For Any Purpose, Part II

You can read Part I here. Here is a link to the original popular press article. 

Last time, I indicated that it is unhelpful to enthusiastically embrace some species as being somehow inherently "remarkable," because it denies the role of the environmental history of the organism. On top of this, such a judgment also says more about human beings than it does the animal (in this case, the octopus). In this installment, I address the following question, pulled from a statement by the study's lead author:

Do the cephalopods' "large, elaborate brains" permit them "to be active predators with complex behaviors"?

On its surface, this point appears harmless and reasonable enough. However, there is an underlying unwarranted assumption that pervades a large amount of work in the biological and psychological sciences.

The issue is one of teleology, or of explaining phenomena in the natural world in terms of their purpose, rather than in terms of their antecedent causes. Many people, laypersons and scientists alike, agree that humans can have reasons for their actions, and that they purposefully act in an intentional, top-down manner. An esteemed philosopher of science, Daniel Dennett, argues that we can and should adopt what he terms "the intentional stance" when it comes to human behavior. We can ask a person their reasons for acting a particular way, and fully* accept an answer that uses terms of one's conscious striving towards a particular goal.

In biology, however, this kind of reasoning is inappropriate. Prior to Darwin, many of the world's greatest thinkers could only conceive of the orderliness of the natural world as being the product of a supernatural entity, a cosmic designer, a God who behaved with purpose. Darwin's theory of evolution tidily dispenses with such explanations in favor of an entirely bottom-up, undirected natural process that produces stunning amounts of complexity. There are no purposes, and there are no goals. Darwin's theory thus flipped our understanding of Earthly life entirely on its head. The continued vociferous religious opposition to modern evolutionary theory is due to the elimination of purpose from the natural world, the express rejection of teleological explanation.

A bird's wings are not intended for flight; monkeys did not evolve responsive prehensile tails to become more agile arboreal denizens; and octopuses did not develop large brains to enable complex predatory behavior. A complete explanation of complex animal behavior does not require that Nature furnish such purposes.

Credit: http://www.jesusandmo.net/

The teleological claim that the animal's large brain engenders their predatory behavior is unfounded if one considers the evolutionary history of the organism. The octopus's large and complex brain was shaped over millions of years as a function of its environment, or, if you'd prefer, its ecological niche. So too, simultaneously, was its tendencies to behave in a manner that humans would eventually observe and find clever. Under the wide scope of this analysis, the brain does not strictly cause behavior in the sense that it "enables" predation or problem solving. Instead, both the brain's complexity and the organism's complex behavior are products of a temporally extended, dynamic, and complex environment having acted on the raw material of evolution. A modern cephalopod's complexity, in both brain and behavior, is a direct product and reflection of environmental pressures to which its ancestors were subjected in a mindless and purposeless process. In a very important sense, the most important issue is not how interesting the octopus is, but how interesting its ancestors' homes were.

We should welcome research that continues to illuminate the scope of the natural world. The data in this specific study appear to be exciting and worthwhile, and the researchers should be given their due credit. However, scientists should be very careful in how we convey the results of our investigations to the public so as to avoid misunderstanding. A mistake too-often made is the ascription of teleological explanations for phenomena that need nothing like "purpose."

Darwin kept a large number of personal notebooks over his life, particularly during the era prior to the publication of The Origin of Species. In the pages of these notebooks, you find the great thinker's thoughts on a wide host of philosophical, political, and scientific matters. During the voyage of the Beagle, he had with him a pad now known simply as the Red Notebook. On its back cover, he wrote four words that reflect an enormous step in his personal evolution, and ones that any practitioner and communicator of science should take to heart:

“Nothing for any purpose.”


*Maybe, maybe not. More on this will be saved for a later discussion.