I think, therefore I am: Mancuso and the mysticism of suffering plants

It is a common cliché in political thought that freedom can be a double-edged sword. This is true even in the academic world, where the damage is considered to be less severe. But this is not true. Academic freedom originated historically to protect academics from political and religious power, not to shield error from scientific criticism. In reality, in Italy we have seen several examples – from the Di Bella case to the Stamina scandal, from anti-GMO propaganda to the campaign treating the human embryo as a person – where the argument was put forward that academics holding scientifically unfounded positions stood on the same epistemological footing as those presenting scientifically corroborated data. ‘Science is divided,’ it was said, or ‘I am a full professor of agricultural sciences and I am qualified to say that GMOs are useless and dangerous. Anyone who says otherwise knows no more than I do.’ Such messages are honey to the ears of relativists. There are cases where no public controversy is at stake, and a qualified scientist, for reasons of self-promotion, spreads nonsensical and misleading claims. How should we characterise such cases? For example, the agrobiologist Stefano Mancuso goes around claiming, in books and at conferences, that plants have a nervous system and conscious cognition based on memory and learning. It is an interesting ‘clinical’ case study of popular science culture.

He is a master at devising evocative metaphors; he has convinced half the Western world that plants think, communicate, suffer, remember… perhaps even have political leanings. One might feel envy for his success, but not for his scientific reputation. Among those who strive for intellectual honesty, there is little sympathy for those who use rhetorical devices to dupe enthusiasts of environmentalist thought or individuals devoted to New Age-style beliefs, while at the same time employing their technical and scientific expertise to counter the arguments of colleagues who seek to expose them as false. Is this a secondary or unintended consequence of freedom of thought? Perhaps.

Mancuso is indeed an expert on real phenomena, namely electrochemical signals or the release of volatile compounds in response to stress, which alter root growth in accordance with chemical gradients. To these signalling phenomena, he applies a mentalistic lexicon without any theoretical justification. Roots ‘decide’. Forests ‘speak’. Mimosas ‘learn’. The logical leap from electrochemistry to cognition – which in neuroscience would require decades of experimental work and rigorous operational definitions – is made by Mancuso with the nonchalance of someone who knows that the TED Talk audience will not ask for the raw data. Mancuso is not naive. He uses his skills to do the opposite of what he claims to be doing. He says he wants to spread knowledge about plants, but in reality he propagates a mysticism of botany which retains only a superficial vocabulary from science, whilst possessing the deep structure of esotericism: the hidden world that only the initiate can see, the truth that official science refuses to admit, nature that speaks to us if only we know how to listen.

Lincoln Taiz, one of the most authoritative living plant physiologists, together with a dozen colleagues, has published a systematic critique in "Trends in Plant Science" of so-called ‘plant neurobiology’, the academic field of which Mancuso is a co-founder and leading proponent. Their central argument is blunt: without a centralised nervous system, without neurons, and without information-integrating structures comparable to those found in animals, applying concepts such as ‘intelligence’, ‘memory’ and ‘learning’ to plants is not a bold discovery; it is a misuse of terminology that obscures rather than illuminates. Words in science have operational definitions, not poetic values. Plant neurobiologists, write Taiz and colleagues, “have consistently overlooked the remarkable degree of structural and functional complexity that the brain had to evolve for consciousness to emerge. […] the probability that plants, with their relative organisational simplicity and lack of neurons and brains, possess consciousness [is] practically zero’. Insects and squid have neural structures that foreshadow a form of consciousness. But for now, conscious plants remain confined to science fiction stories. Moral guilt towards nature – deforestation, climate change, industrial agriculture – is an emotionally addictive trope. Discovering that plants suffer and communicate transforms the reader into a sensitive witness to a cosmic tragedy. It is a powerful, psychotropic sedative for collective anxiety about scenarios perceived as dystopian.

Mancuso’s true masterpiece lies in having carried out this operation within the context of a respectable academic career, complete with a professorship, international awards, but above all a regular presence at cultural festivals, where the audience applauds him without understanding. He is the perfect model of the postmodern populariser: scientific enough not to be dismissed as a charlatan, vague enough not to be discredited as a scientist. An epistemically invulnerable position, and therefore a privileged one in pseudo-cultural contexts. Some might still say: ‘So what? He’s not doing any harm.’ It depends. A professor who teaches, paid from public funds: things that certainly won’t help his students form a meaningful understanding of the plant world. He does cause some harm.

But there is academic freedom! Quite rightly, only the peer community, through peer review and the assessment of curricula, can defend scientific culture from ridicule and from becoming a source of harm to students, who are in a position of epistemic asymmetry vis-à-vis the lecturer. If decisions were taken at a political level, it would be just as possible to ban heliocentrism. The mechanisms exist: course accreditation, which should include an explicit assessment of the scientific soundness of the curriculum content and not merely its formal aspects; scientific societies in the relevant fields can produce position statements defining what is scientifically sound for teaching; professional bodies, where they exist, should condemn training that produces professionals with false beliefs about empirical mechanisms. Academies should exist not only to lobby, but also to produce documents that distinguish between what is scientifically established and what is mere misleading rhetoric for those who study and wish to learn what is produced through the scientific method. But academic freedom is always misused as a shield, and institutions rarely have the courage to distinguish between the protection of genuine critical thinking and that of organised error. Meanwhile, plants, oblivious to all this, continue to photosynthesise. Not because they have decided to do so. Nor because they remember doing it last time. But because they have enzymes that function in a specific and necessary way. It is less anthropomorphic. But it is reality, according to the facts.