Since reading Metaphors We Live By by Lakoff and Johnson (1980) I have been fascinated by metaphors but I was left wondering what role could metaphor plays in scientific practice. Many scientific disciplines deal in abstract concepts and objects invisible to the naked eye, so metaphors definitely come in handy when communicating these ideas to the broader public, but is there anything metaphors can do for scientists themselves? In my own field of neuroscience a classic metaphor (which I heavily exploited in my book Neurocomic) is the one of 'neurons as trees' and the 'brain as a forest'. This metaphor, far from being used only in education, has become an intrinsic part of our technical jargon. Everyday neuroscientists talk of dendritic 'branches' and axonal 'arborizations', and when tiny structures were observed on these branches they were named 'spines' (not hairs, nor feathers, nor bumps). In short, it seems that we not only describe neurons as trees but over time we really came to think of neurons as trees.
I found myself going back to this metaphor while reading Making Truth: Metaphor in Science (2003), in which Theodore Brown convincingly argues that metaphors, even before entering the public domain, can play a fundamental role in scientific discovery. Giving many insightful examples - especially from the history of the atom - Brown shows how, long before a concept is well understood, metaphors can help scientists to come up and perform experiments, therefore guiding scientific progress itself. The only issue I have with Brown argument is that it seems to conflate ‘metaphors’ and ‘models’, but is every model really a metaphor? I think physicists could argue that some of their models are truly abstract and purely mathematical at an early stage. However, there is no doubt that metaphors and thought experiments (or shall we call them narratives?) such as Maxwell’s demon, Schöredinger’s cat and Einstein’s twins played a major role in the acceptance of the underlying models. Indeed, in Real Science (2002) the physicist John Ziman claims that “scientific theories are unavoidably metaphorical".
If metaphors are not simply a byproduct of science but can really guide discovery itself, then carefully choosing these metaphors becomes an integral part of scientists work. Of course, as Brown points out, a metaphor is rarely chosen by a single individual once and for all, many unsuccessful metaphors are proposed until one eventually emerges, when it is colloquially used and expanded upon by other scientists. Nonetheless, the initial choice can have far reaching consequences and should not be taken lightly. When a metaphor becomes established it may be difficult to abandon and can lead a field astray for years, even decades. In fact, Brown's metaphors/models are at the core of what Thomas Kuhn described as 'paradigms' in The Structure of Scientific Revolutions (1962). Kuhn himself seems to acknowledged the importance of metaphors, in Metaphors and Through (1993) he claims:
“Metaphors play an essential role in establishing links between scientific language and the world. Those links are not, however, given once and for all. Theory change, in particular, is accompanied by a change in some of the relevant metaphors and in the corresponding parts of the network of similarities through which terms attach to nature.”
There are many examples of metaphors 'gone wrong'. One of my favourites, from Making Truth, is the 'greenhouse effect' metaphor which, although useful to understand some aspects of climate change, it has been criticized because it carries associations with the protective and pleasantly warm environment of a greenhouse. Also, it fails to capture the complexity of climate change, focusing too much on global warming, while missing other important aspects such as ocean acidification. In short, as the field grew, the greenhouse metaphor became too prescriptive and eventually fell out of favour. Some metaphors, however, are so deeply rooted in our culture that are difficult to abandon. In Illness As Metaphor (1978) Susan Sontag discusses how different incurable diseases throughout history became metaphors of death itself, carrying with them stigma and superstition. Another more recent example of such harmful metaphors, is the bellicose language used to discuss cancer treatment (the 'battle against cancer'), which can have the side effect of discouraging preventive behaviours (Hauser and Schwarz, 2015).
Ultimately we could argue that metaphors will always involve an oversimplification and maybe they should be avoided altogether in science. But if we accept Lakoff's argument that metaphors are not only useful but necessary for human cognition, then it follows that scientists should put much more time and though in their choice of metaphors. However, since there is no formula for concocting a successful metaphor, scientists can only rely on their own creativity and spontaneous associations. This is why some visual thinking and creative writing should probably be part of a scientist's education. Indeed, Brown concludes:
“[Teaching science] involves imparting conceptual understanding and a sense of intellectual excitement about the subject. The creative use of metaphors is a vital element in that process.”
Brown, T.L. (2003). Making Truth: Metaphor in Science (University of Illinois Press).
Hauser, D.J., and Schwarz, N. (2015). The war on prevention: bellicose cancer metaphors hurt (some) prevention intentions. Pers. Soc. Psychol. Bull. 41, 66–77.
Kuhn, T.S. (1962). The Structure of Scientific Revolutions: 50th Anniversary Edition (University of Chicago Press).
Lakoff, G., and Johnson, M. (1980). Metaphors We Live By (University of Chicago Press).
Ortony, A. (1993). Metaphor and Thought (Cambridge University Press).
Sontag, S. (2001). Illness as Metaphor and AIDS and Its Metaphors (Macmillan).
Ziman, J. (2002). Real Science: What it Is and What it Means (Cambridge University Press).