Plants, in nature conservation and beyond, are commonly treated as third-division players. They are “not like animals”, and are very much “not like us”. But there is a faint glow from an alternative view of what plants are.
“It is hardly an exaggeration to say that the tip of the radicle [root of a flowering plant] acts like the brain of one of the lower animals….”
Darwin (1880) The Power of Movement of Plants
“It is hardly an exaggeration to say that the tip of the radicle [root of a flowering plant] acts like the brain of one of the lower animals….”
Darwin (1880) The Power of Movement of Plants
A point of view
This essay briefly looks into part of our changing understanding of plants, but it is an aspect that potentially could bring a change in how we think about our relationship to them, and perhaps to how we approach their conservation. 
I do not agree with all the implications that some other botanists point to, but I sympathise with their attempt to draw more attention to plants, and to our predominant attitude to them. Doubtless, there will be arguments about this for a (further) long time; and a language in which it can be discussed that is not predominantly zoocentric – if not anthropocentric – has yet to be developed. In that respect the present state reminds me of the feminist endeavours of the 1970s. 
In Man and the natural world, Keith Thomas quotes a delightful anecdote about a nineteenth century English country gentleman, whose greatest pleasure was to sit out of doors of an evening in sight of the grand old trees in his park, and before going in he would walk round to visit them, one by one, and resting his hand on the bark he would whisper a good-night. 
Of course, as one might explain, this is the sort of thing some old men – and women – still do, though only the sillier ones think that any talking to plants is as rationally sensible as, say, talking to one’s dog – and only the very silliest believe they get an answer. At the moment, however, the supposed silliness of such things is itself the subject of discussion, even a little serious academic discussion, and it may be that we conclude that it makes sense, and we need to rethink just what such things as trees really are.
We have become used to tree-huggers amongst us, and they cause us little rethinking, as their actions are largely symbolic and one-sided, not acts of intimacy between fellow beings.  Tree (or bunny) hugging is about on a par with the position of lawyers who argue that trees have legal standing, that is should be recognised as having legitimate interests that can be argued – for them – in court. Trees, so far as most of us are concerned, do not say “Good-night”, and do not plead not to be felled. Indeed, in the nineties a sweet chestnut tree in Wanstead, Greater London, became quite famous, threatened (as we say) with felling as it was in the way of London’s M11 motorway. It had four hundred letters of support delivered by the postman, but it answered not one of them. 
Its supporters – letter-writers, and protesters roosting amongst its branches – may well have acted as if trees think and talk, but that was pressing theoretical equality too far ahead.
Most people in our society are more inclined to regard trees – or rabbits, or grass, even dogs – as resources rather than as pets or friends. Indeed, this is effectively how we think of members of some other human societies, as well as ‘disadvantaged’ members of our own…. Some snakes, slugs and flies, of course, are seen as problems, even if they are shown to be ‘service’ providers. Plants may be alive, but they are not like us – not even like snakes or slugs. Being very unlike us, we can do much as we like with them. (We still have shadows of a similar attitude to ‘natives’.)
And so we do. A few years ago, I read that our goal is to have such exquisite control over the genetics of living systems that instead of growing a tree, cutting it down, and building a table out of it we will […] be able to grow the table. 
And yet, a small but increasing number of people are dismayed by our behaviour towards the vegetable world. Dogs often command respect, and a moral consideration. Rabbits usually have less; and plants are normally of secondary consideration, even when their ornamental value is appreciated, and even by nature conservation. Anger at their plight is commonly less than for animals.
“I never thought of that before!” she said. “In my opinion you never thought at all,” the Rose said in a rather severe tone.
Although, as with Alice in Lewis Carol’s Through the looking-glass, talking to plants is common, few people expect a reply. To most of us, plants are alive but zombie-like, and as inarticulate as the famous house-brick. This, however, may be a slightly harsh judgement.
In the last few decades, green plants have, in some quarters, have been a bit more discussed than they were. In 1974, Christopher Stone’s Should trees have standing?  argued for legal rights for natural objects – for example, that trees in the Sierra Nevada, although they could not speak for themselves in court and present a case against their felling, had ‘standing’ in the American law system that should allow them to be represented, and ‘their’ case to be presented by humans. “Silly”, said many; “Er…?” was perhaps the general reaction. “Well… wait a minute”, said a few.
In part, such majority reactions result from the problem of discussing plants in words and meanings that have been developed for discussing animals – a run-on of the problems in discussing ‘lower’ animals with a language developed for humans. In the current paradigm it is silly to talk of roses speaking; it is not, though, quite so silly to talk of them conveying messages to us.
A new language?
A century ago, after his expedition collecting plants for Western gardens, E. H. Wilson was grateful that the vegetation he had seen he had not also heard – for the exultations of the victors and the groans of the vanquished would be too much for humanity to bear. 
This language is quite different from the tradition of scientific prose. It is language that, as it were, lets us into the ‘minds’ of plants, much as many other naturalists’ writing, and scripts of some broadcasters, puts us as it were into the minds of animals. I read or hear these as examples of poetic styles – but what if they were intended as objective, ‘neutral’, descriptions? As such, they are heretical, as they cameo plants that feel joy, or suffer pain and anguish, with which we are considered to be empathetic.
The idea of a neutral language, an unemotional, unpassioned one, and of soberly neutral judges, seems almost ready to fall on its face. It is also accepted by many who have had a science education that ‘neutrality’ is a theoretical, or imagined, objective. 
Wilson’s description is unscientifically poetic; it is (let’s assume) only imaginary, yet the images are not lightyears from what a modest thread of scientific writing about plants is saying. It is not impossibly far from a rethinking of plants that is establishing itself amongst iconoclastic botanists.
There has long been a trickle of heretical views of plants that present them as ‘sentient beings’, and sometimes as having awareness, consciousness, and/or mind, or being ensouled. “Aristotle’s dogma”, say Tomkins & Bird, introducing their controversial 1973 book The secret life of plants, that plants have souls but no sensation lasted through the Middle Ages and into the eighteenth century… 
Work by scientists such as Jagadish Chandra Bose, and Raoul Francé  carried the trickle into the twentieth century, and The secret life – quite widely read, though dubious biology – took it towards the present one. Most readers did not see plants as sentient, thoughtful beings that preferred Ravi Shankar to Bach, and shrivelled from rock; but a few did.
In the last few decades, a more coherent stream of discussion has arisen, for such things as the ‘awareness’ plants have of where they are and how they are faring, the similar ways plants and other living things ‘sense’ their world, and the ‘communications’ both within and between individual plants.  Notwithstanding there is unrestrained discussion of these things in the ether, this is an academic stream of discussion, and it is two academics’ books I want to touch on now, as an introduction to some of this recent, patchy, minority thinking. 
More complex and more interesting
We don’t expect plants to up-root and stump around the landscape Ent-like, until they find where they want to grow, but that doesn’t mean that they don’t (in some sense) ‘know’ that, say, their roots have just happened on a nutrient-rich patch of soil, or that one of their branches has just been lopped off. If they didn’t ‘know’, they’d probably be dead!
What a plant knows is written for lay readers by an internationally respected botanist. Dan Chamovitz reviews up-to-date interpretations of a plant’s ‘senses’ – what it ‘sees’, ‘smells’, ‘feels’, and ‘hears’ -, of what it ‘knows’ about the world it is growing in, what it ‘remembers’, and about what has happened to it, and of the accumulating evidence for chemical communication between plants.
These common English words can seem odd when applied to plants, but if we can get past the chauvinism that boxes us out of the lives of almost all other life forms, it is pretty clear that to ‘do’ anything it helps a plant to have – via ‘senses’, just as we are used to with slugs, frogs and dogs – some sort of information about its surroundings, and to react to its circumstances. While making it clear that a plant is not “just the same” as an animal, one of Dan Chamovitz’s concerns is that we should blunt the sharp distinction between things we call plants and things we call animals. (Again, I’m leaving aside the microcosm and various oddities of life.) Although these words are usually associated with ‘consciousness’ of some sort, this is not necessarily implied: what is, is sentience.
Like many other words used in discussing this subject, ‘sentience’ is a bit weaselly. If we go with the Oxford English Dictionary, we use it to mean “[capable of] feeling”, “conscious or percipient of something”, “responsive to sensory stimuli”; or we might say it’s about something that is aware of what is happening around it. This shifts the burden of meaning from word to word, but I’m not sure it clarifies much. However, ‘sentient’ is also now frequently used with the meaning “[having] the capacity to feel pain and experience pleasure or the capacity to suffer and enjoy”, and “having the power to experience a sense of well-being or suffering”.  This is the sense I want it to carry here.
Plants, like us, respond to stimuli: that is, they ‘behave’. We tend to down-play plants’ behaviour, arguing that they don’t ‘think about’ their situations as we do…. And something of this attitude is, of course, applied to most if not all animals. The idea that dolphins and apes, and perhaps pet dogs, think about their situations, albeit as “through a glasse darkly”, largely remains in the realm of silliness – and the realm of imagination. But this is not where Dan Chamovitz is trying to point us. His message is that plants are more complex, and so much more interesting, than we thought, that biologically they do things we and the rest of living things do (albeit in different ways), and that, though we are deaf to it, there is a sort of ‘vegetable conversation’ going on all the time.
Is it silly?
If some or all of this seems silly, that is partly because we have placed H. sapiens at the head of Life’s procession, with things less and less like us further and further back – and that puts plants a long way behind us. It has not always and everywhere been like this.
In many traditions, it was commonly understood not only that plants are alive, but that they are aware. In surviving traditions around the world, plants are frequently given equivalence with animals, and sometimes with humans. And there are instances where plants are placed morally ahead of humans – romantic echoes of which, perhaps, we can find in our own culture, such as the virgin whiteness of the lily, and the image of the flowers of the field mirroring of our tribulations.
Matthew Hall’s Plants as persons is not scientific botany, but – as its subtitle says – a philosophical botany. It is a rather less easy read than What a plant knows, and its style distinctly academic. Like Chamovitz, however, Hall deals with signs of a shifting attitude to plants, in his case showing mostly attitudes that prevailed in the past, with an eye to their reestablishment amongst thinkers today. His aspiration for the book is to seek our “most appropriate behavior towards plants”, and to reduce our general ignorance of things vegetal, as well as a predominant zoocentrism.
We begin (as usual) with the Greece of Aristotle, whose teachings on plants were based on their contrast with animals, and of Aristotle’s successor Theophrastus, who saw plants as volitional, minded, and intentional. In the subsequent Western tradition, a systematic devaluation of parts of nature began long before Descartes’s philosophy; our relationship with plants has long tended to be instrumental. Today we are supposed to talk of the ‘services’ they offer us. Services are the work of servants…. This encourages the relegation of plants to the bottom of the hierarchy of life, and their exclusion from moral consideration. Moreover, with such a hierarchy in mind it is easy to avoid thinking of all organisms as components of (eco)systems.
By contrast, in Eastern traditions, a hierarchical separateness is less evident, and plants are more readily accepted into the human orbit. In parts of the Hindu tradition, they are seen as sentient, and having mental activity. They can be harmed by human actions, and are therefore seen as being subject to our moral concern. In parts of this tradition, reincarnations may, apparently, include plant forms.
For Jains, non-violence to all organisms is of central concern. Jainism is distinct for stressing that other organisms’ interests are to be taken into account in any consideration by humans. Plants have, like other organisms, a ‘sentient soul’, and sensation. They are also thought of as emotional.
The main development from Hinduism, Buddhism, seems to have an inordinate complexity in which attitudes to plants vary from sidelining them to considering them of superior worth. Early texts appear to indicate sensorily aware beings afforded considerable moral standing. Later, in some forms of Buddhism, plants’ sentience was left ambiguous. 
Becoming kindred again?
In Europe’s pagan cultures, plants were commonly regarded as kindred, requiring relationships of “care, solidarity and responsibility”. Matthew Hall explores pagans, plants and personhood before Europe’s Christianising, looking at such sources as the Icelandic Eddur, descriptions of the Druids, and the Welsh wonder-tales of the Mabinogion. Looking at a variety of ‘indigenous animisms’ around the world, Hall feels that here may be insights to help us be more open to other ways of knowing the world, not least because of their inclination to see ‘other-than-human persons’.
This looks a difficult task, though similar changes, such as a rise of shamanistic thinking, have happened. What, I think, is just as likely is that tree-hugging and whispering good-nights to them will increase, along with revelations of yet more ‘miracle foods’, and exhortations that talking to flowers counters numerous (human) ills. This would probably draw attention away from the state of the plants themselves.
In his final chapter, Matthew Hall highlights some of the new botanical-science thinking, for instance on what is now called ‘signalling’ by plants, and ‘plant neurobiology’, and he notes that over the past century or so, science has gathered evidence that plants are not passive and insensitive. He raises the question of ‘mind’ in plants. Again, we have words used outwith their comfort zones.
The debate on ‘plant intelligence’ is unfortunately plagued with conceptual traps. Intelligence is usually cashed out in animal or anthropocentric terms, in such a way that plants plainly fail to meet the conditions for animal- or human-like intelligence. […] It goes without saying that plants do not share ‘neurons’ with animals […]. 
A new stable, and widely adopted, technical language would be a great advantage in this situation. 
Swiss optimism, New Zealand action & Aotearoa satisfaction
There is a growing literature and widening discussion on the subject, much of it scientifically unsound.  Certainly, some of it is a welcome antidote to a zoocentric environmental philosophy – and more specifically to nature conservation philosophy – that obliges us to examine plants from new viewpoints. If we can get beyond seeing all this as modern-day mumbo-jumbo and the softening of science into fairy stories, might we find that there could be something here of interest to nature conservationists?
It is perhaps optimistic to think that readers of Ecos are going to have an enlightening experience from reading this; and I don’t expect knowing something about Hall’s and Chamovitz’s books to result in born-again shamans (though perhaps vegans); but there might be a few who catch hold of evidence for the unexpected but fairly explicable things plants seem capable of. That may or may not include commanding more ethical consideration and respect.
I happened on a clear if simplistic view of this subject, which enthused but cautioned – and reminded readers that the simplest, most parsimonious explanation that squares with the evidence might gain most respect from fellow scientists. The writer’s example – that a plant growing faster to try to surpass a rival and gain more light is a “genuine expression of intelligence” –
may be described as a straightforward physicochemical response to the amount of light available.  This, however, misses the significance of any cooperation between plants. What parsimonious explanation squares with the suggestion that, though we are deaf to it, there is a sort of ‘vegetable conversation’ going on all the time? It depends, of course, on what you mean by ‘conversation’….
Does such ‘evidence’ make an impact on the non-scientist? On some: one example that has received a little attention is that the Swiss Federal Constitution now requires account to be taken of the dignity of living beings when handling animals, plants and other organisms, following deliberations by the Swiss Federal Ethics Committee on Non-Human Biotechnology.  One response to this suggested that “dignity of plants” is nothing but a sign that we are promoting the absurd. And a defence of it states that “plants are living beings, so they also have dignity, and that “claims that plants have no subjective sensations are as speculative as the opposite.”
Dignity in terms of plants is a difficult concept. It is religiously charged and comes from history of mankind. However the notion could be understood as a sign that plants are to be respected and [that we have] obligations towards them. 
This seems sincere but unclear… And remember how far the campaigns for even hominid apes still have to go. Can it be that seeing plants in a new light makes it easier to argue that they should have the same status and respect as, say, slugs, spiders, and swallows? This wouldn’t be a great advance up the security ladder, but it would be a start. Should trees have standing? has made some progress against status quo opinion, and this new thinking should strengthen the case for extending our moral consideration to the rest of the vegetable world. Considering that plants could feel pain might make us more careful in our management of them: considering that they have interests in their own right, or that they have at least some “right to thrive”, might make us think more carefully about our assumed right to use them – even if the use is only for their ornamental value.
Perhaps not. Bestowing ‘rights’  is not a guarantee of change in what we do. Believing that a slug can feel pain doesn’t stop many gardeners chopping them in two with a spade… without knowing that most are innocent. Elephants are still shot for their teeth; whales are still harpooned “for science”.
There are one or two countries whose laws state that because whales and dolphins (and a select few others) are sentient, conscious, emotional, and clever, our moral code must extend over them, and they must have legally-enforced protection – yet almost everywhere they are (as we would probably say if they were proper persons: i.e. humans) persecuted. I suspect, however, that the crack in the status quo – the present paradigm – is actually a fraction wider than this. In New Zealand, in March 2017, rights, the same as those given to a person, were given to the Whanganui River. For Maoris, this was the culmination of 140 years of negotiation over what they regard as their ancestor. 
Are there yet any signs of our actually becoming nicer to plants? It’s no surprise that there aren’t many. Dan Chamovitz refers to the Swiss The dignity of living beings. Its conclusions include the committee’s unanimous or majority agreements that an “arbitrary harm”, such as the beheading, without rational reason, of roadside flowers, is morally impermissible; that the complete instrumentalisation of plants “requires moral justification”; that plants may not be owned absolutely; but that any action serving human self-preservation is justified, if it is “appropriate” and done with precaution. Such statements seem to me to be pointing in the right direction, but built on weak foundations from material of unproven quality. They look theoretical… but the potential could be great.
As an attempt to start redefining our relationship with the plant world, these are little steps on an uphill track. But… it’s a start.
So what is the potential? It may be that we come to understand that plants ‘speak’ to us, not with words but through numinous dreams and visions, telekinetic conversations and songs, [and teach us] of their role in supporting the physical, psycho-emotional, and spiritual growth of humanity […]  but for me it begins with the expectation that plants – but not only plants – will be shown to be rather more complex creatures than we thought, able to do more than we expected, including spreading ‘messages’ (or ‘signals’) to other beings and receiving ‘messages’ from them. Whether or not such communication includes us, I don’t know. We have enough new information to be fairly sure that a plant’s physiology is not as straightforward as we thought; and we shall almost certainly have to devise new models of a plant’s development and behaviour, and modify our language so that we can describe them. We are already having to quite drastically change our understanding of how plants – but not only plants – have evolved; and I would not be surprised if our present model of relationships between several discrete ‘kingdoms’ (as the Enlightenment called them) has to go the way of dishwater. This is not just because of the sort of research Hall and Chamovitz describe. Genetics is changing rapidly; and our established meanings for ‘species’ – let alone ‘genus’, ‘family’, etc. – seem likely to follow the kingdoms.
We are discovering some interesting things, but tend not to recognise the changes they imply However, if such ‘objective’ changes – such paradigm shifts – happen, it should, I believe, become easier to think of ourselves as (much) less unique than we do now, and easier to see that morality – the manifestation of ethics – can be applied far more widely than it presently is. It would also, I think, be likelier that we would more readily think of Homo sapiens as part of an ecosystem; that this Latin tag is a convenience to pigeonhole a community; and that – perhaps – this particular community is important only because there is so much of it….
Notes & references
- Quite how our approach could be altered, I admit I can’t see in any detail. What I do see is that it changes our relationship with – to be old-fashioned – a whole Kingdom of organisms, in line with changes that are happening – with agonising slowness – to our relationship with Animals. As usual, most of us haven’t really noticed that we are in intimate relationship with the microcosm. In line with most of my references, I have left ‘plant’ undefined: It nearly always means Angiosperms.
- An example is Mary Daly’s Gyn/Ecology, Women’s Press, London, (1979) – interesting for its attempt to make changes in English.
- Keith Thomas (1982) Man and the natural world. Changing attitudes in England 1500-1800, Allen Lane, London.
- The personal instance I wrote about in A lesson from an old oak Ecos 37 (3-4) 44-48, (2016) certainly wasn’t.
- It was felled. A booklet, Dear Tree, was issued by the No M11 Link Road Campaign.
- Rodney Brooks (2002) The merger of flesh and machines, in The next fifty years. Science in the first half of the twenty-first century, ed. John Brockman, Weidenfeld & Nicolson, London.
- Christopher Stone (1972) Should trees have standing? Towards legal rights for natural objects, William Kaufmann, Altos CA. Enlarged edition by Oxford University Press.
- Ernest Wilson (1913) A naturalist in western China, Methuen, London.
- Language seems to be a common issue for science. We may expect ‘the literature’ to be written dispassionately and ‘neutrally’… but it is written by humans. Vocabularies are stretched (or shrunk) to suit new understandings, although these may continue to change, and although the old meanings still remain, if only as shadows.
- Peter Tompkins & Christopher Bird (1973) The secret life of plants, Harper & Row. See Richard Jones (2013) The medieval natural world, Pearson, Harlow; and Keith Thomas .
- Bose’s writing includes Plant response, 1906 and The nervous mechanism of plants, 1926. Francé published Germs of mind in plants in 1905.
- Plant communication has received relatively much attention, both plant-to-plant and plant-to-other-organisms – humans included. It illustrates some of this area’s problems. ‘Communication’ has shades of meaning, not all of which require two or more participants who know that they are participating. Some usage does not seem to require that any organism ‘knows’ it is giving or getting a ‘communication’.
- David Chamowitz (2012) What a plant knows.. A field guide to the senses of your garden – and beyond, Oneworld Publications, Oxford. Matthew Hall (2011) Plants as persons. A philosophical botany, State University of New York Press.
- Richard Sylvan & David Bennett (1994) The greening of ethics, White Horse Press, Cambridge, quoting Peter Singer; Luke Martell (1994) Ecology and society, Polity Press, Cambridge.
- E.g. Ellison Banks Findly (2002) Borderline beings: plant possibilities in early Buddhism Journal of the American Oriental Society 122(2) available online. For Buddhism’s ambivalent attitudes to nature and environment, see Lambert Schmithausen (1997) Early Buddhist ecological ethics Journal of Buddhist ethics 4, 1-74.
- Fracisco Calvo Garzòn (2007) The quest for cognition in plant neurobiology Plant signalling and behaviour 2(4) 208-11.
- In English, there are echoes of early human-anatomical terms throughout biology. The common language as well as academic ones retains examples. Richard Firn (2004) Plant intelligence: an alternative point of view, Annals of Botany 93: 245-51, advises that “if new words are needed to describe how plants function, maybe we should invent new ones, rather than trying (sic) to redefine existing ones.”
- Back in 1974, in The secret powers of plants, Brett L. Bolton has chapters called ‘Do plants feel?’, and ‘Are there parallels between man, animal and plant?’, but also ‘Do plants respond to prayer?’, and ‘Do plants think?’. At least these all seem fairly clear. Patrice Bouchardon (1998) The healing energies of trees, Gaia Books, London, 1998, is an example I find less so: “In a meeting with a tree our energy fields react and adapt to the tree’s energy field and attune to its qualities .” If such an example is poetry, fine; but it usually isn’t.
- Mikel Mancuso (2014) Brilliant green book review, Berkeley science review, online Fall 2014.
- The Federal Ethics Committee report, ed. Ariane Willemsen (2008) The dignity of living beings with regard to plants, available online. An E.C.N.H. paper ‘Dignity of living things’, sets the context: www.ekah.admin.ch/en/topics/dignity-of-living-beings .
- Letters in Plant signalling and behaviour: Simcha Lev-Yadun (2008)‘Bioethics: On the road to absurd land’, 3: 612; Florianne Koechlin (2009) ‘The dignity of plants’, 4¨78-79.
- We tend to forget that most often when ‘rights’ are mentioned what is meant is something that is given or allowed by people in authority.
- Paola Cavalieri & Peter Singer (1993) The Great Ape Project. Equality beyond humanity, Fourth Estate, London. New Zealand was the first state to legislate for rights for non-human hominids in 1999 (Spain’s Balearic autonomous community did so in 1992). And now a ‘New Zealand river granted same legal rights as human being’, Guardian website 16 March 2017; ‘Whanganui River given legal status of a person under unique Treaty of Waitangi settlement, Wanganui Chronicle website 15 March 2017. The Te Urewera National Park was given a similar status in 2014. A year later, ‘Nature has rights too says pope, in call to protect environment’, Guardian 26 September 2015.
- Monica Gagliano (2018) Thus spoke the plant, Berkeley: North Atlantic Books (the Society for the Study of Native Arts & Sciences). Her intention is twofold: to show and explain scientifically more of the capabilities of plants; and to describe her own experiences of plants, “as they had done for millennia, [teaching] of their role in supporting the physical, psycho-emotional, and spiritual growth of humanity”. The book is reviewed in this issue of ECOS, from a viewpoint somewhat different from mine.
Martin Spray has been a longstanding editor of and advisor to ECOS. He is a retired botanist and an unretired sceptic. He is grateful to Alison Parfitt, Gerald Dawe, and Jane Spray for comments on the draft of this article.
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