Michael Levin and Daniel C. Dennett in Aeon:
Biologists like to think of themselves as properly scientific behaviourists, explaining and predicting the ways that proteins, organelles, cells, plants, animals and whole biota behave under various conditions, thanks to the smaller parts of which they are composed. They identify causal mechanisms that reliably execute various functions such as copying DNA, attacking antigens, photosynthesising, discerning temperature gradients, capturing prey, finding their way back to their nests and so forth, but they don’t think that this acknowledgment of functions implicates them in any discredited teleology or imputation of reasons and purposes or understanding to the cells and other parts of the mechanisms they investigate.
But when cognitive science turned its back on behaviourism more than 50 years ago and began dealing with signals and internal maps, goals and expectations, beliefs and desires, biologists were torn. All right, they conceded, people and some animals have minds; their brains are physical minds – not mysterious dualistic minds – processing information and guiding purposeful behaviour; animals without brains, such as sea squirts, don’t have minds, nor do plants or fungi or microbes. They resisted introducing intentional idioms into their theoretical work, except as useful metaphors when teaching or explaining to lay audiences. Genes weren’t really selfish, antibodies weren’t really seeking, cells weren’t really figuring out where they were. These little biological mechanisms weren’t really agents with agendas, even though thinking of them as if they were often led to insights.
We think that this commendable scientific caution has gone too far, putting biologists into a straitjacket that prevents them from exploring the most promising hypotheses, just as behaviourism prevented psychologists from seeing how their subjects’ measurable behaviour could be interpreted as effects of hopes, beliefs, plans, fears, intentions, distractions and so forth.