There are so many examples (many due to the experimental and scholarly efforts of George Lakoff and his colleagues) that demonstrate the ways in which we invoke metaphor both to make sense of the world around us and to communicate our understanding to others that we should avoid falling into the trap of believing that metaphor is some kind of all-powerful philosopher's stone that can transmute confusion into knowledge (even if I had to resort to metaphor to make this point). The "darker side" of metaphor is so fundamental to Richard Lewontin's latest New York Review article, "Not So Natural Selection," that it occupies his lead sentences:
Nothing creates more misunderstanding of the results of scientific research than scientists' use of metaphors. It is not only the general public that they confuse, but their own understanding of nature that is led astray.
As one may guess from the title of this article, Lewontin is specifically concerned with the extent to which the figurative connotations of the phrase "natural selection" can be misleading. The greatest problem involves that word "selection," whose literal usage tends to presume that there is some agent doing the selecting. Thus, even if Darwin's model emphasized the "natural" modifier (an emphasis reinforced by the scientific arguments posed by Richard Dawkins, particularly in his Blind Watchmaker book), it is hard to resist the temptation to believe that some form of purposive choice is taking place. (Lewontin even reminds us that Alfred Russell Wallace explicitly warned Charles Darwin about this risk.)
We should not take Lewontin's arguments as a dismissal of the cognitive value of metaphors but as a reminder that we have to be careful about how we "live by" those metaphors (to appeal to the title of the 1980 book by Lakoff and Mark Johnson). We tend to think of metaphor as a one-way arrow that transports categories and relationships from their literal domain to a figurative one in which they inform our interpretations of new situations. However, sometimes we have to reverse the arrow, which amounts to using the figurative world to create new categories and relationships for the literal one. Thus, in Darwin's model the operative concept is one of survival and the processes by which certain species endure longer than others (as in differential reproduction). In the figurative world the species that endure have been "selected;" but the value of the metaphor is that it leads us to accept differential reproduction as a new concept to be invoked in our sense-making activities.
My own thoughts about such two-way arrows first emerged from Margaret Atwood's efforts to introduce new literary categories as a strategy for making sense of the current economic crisis. My post about Atwood was entitled "Poetic Wisdom in Practice," acknowledging a concept of Giambattista Vico long rejected by positivist rationality. Unfortunately, positivism is limited to the objective world, which does not always serve the "messier" aspects of reality particularly well. Atwood was trying to deal with the messier social side of economics; but "life itself" is just as messy. Given our cultural preferences for scientistic thinking, we clearly need to be reminded of this regularly; and it is valuable when the reminder comes from a scientist as reputable as Lewontin.