Deleuze and Guattari on the Rhizome: One or Many Plants?
Introduction
What does it mean to take plants as the model for thinking? Gilles Deleuze and Félix Guattari, the figures I want to focus on in this short piece, talk about a ‘vegetal image of thought’. In fact, Deleuze and Guattari do not so much offer a vegetal image of thought, but a vegetal taxonomy of thought that draws distinctions between trees, plants with fascicular root systems, and rhizomes. Now, Deleuze and Guattari are unusual here, since often, when philosophers are talking about plants, they are understanding them as a particular case of life in general. Even Goethe understood his Metamorphosis of Plants as a special case of a more general project of morphology. I want to explore a couple of the main metaphors about plants that have been used by philosophers for thought here, before looking at how a more positive, and more nuanced, appraisal of vegetal thought leads us to fresh possibilities for understanding thinking.
The two metaphors I want to introduce here are those of the tree, and of the organism. The idea that knowledge can be understood in terms is perhaps most clearly set out by Descartes in his Principles of Philosophy, where he writes that:
Thus the whole of philosophy is like a tree. The roots are metaphysics, the trunk is physics, and the branches emerging from the trunk are all the other sciences, which may be reduced to three principal ones, namely medicine, mechanics and morals.*
This tree was expanded and systematised by Diderot and d’Alembert in the 18th century for their Encyclopaedia to include the broader range of the sciences. Here is an image of it:

The tree moves from the more general to the more specific, so it provides a way of understanding how we can determine the nature of something by progressively adding specifications to it. Aristotle elevates this game of ‘animal, mineral, vegetable’ to the rank of highest philosophical method (best captured by Porphyry’s tree, named after one of his commentator), and this idea of an arborescent system of specification is still central to much of philosophy today.

The phylogenetic tree, for instance, shows the relations of different plants and animals to each other by showing how they emerge through a branching structure from a common ancestor. Here is Darwin’s early draft of it:

The second common metaphor is that of the organism. What do we mean by an organism? If we understood the world solely according to the categories of physics, then there would be no organisms at all, but instead a bewildering flux of particles. An organism would not even be a heap of particles, since as we know, living beings are constantly changing the matter that makes them up. What allows us to see organisms as organisms is traditionally the idea of a unity. The German philosopher, Immanuel Kant, defines this as follows:
[J]ust as each part exists only as a result of all the rest, so we think of each part as existing for the sake of the others and of the whole, i.e. as an instrument (organ).*
What Kant is suggesting here is that what determines an organism to be an organism is the idea of purpose. We can understand this in two ways. First, what defines the parts is that they perform a function in terms of the organism as a whole. So even if the matter that makes up an organ changes over time, we can say it’s the same organ if it performs the same function. Similarly, we can understand the function of the organism as a whole by understanding the parts. Georges Cuvier, one of the most important anatomists of the 19th century, used this claim to reconstruct dinosaur fossils, arguing that the functions of the small number of recovered bones allowed us to infer the functions, and hence structure, of the rest.
Now, this idea of the organism translates fairly directly into the world of philosophical thinking, because the idea of all the parts relating together naturally leads to the idea of systematicity. Plato takes up this idea in the Phaedrus, for instance:
Every discourse must be put together like a living creature, with a body of its own; it must be neither without head nor without legs; and it must have a middle and extremities that are fitting both to one another and to the whole work.*
I’ll come back to some of the implications of this in the next section, but for now, we can note two features of the notion of the organism. First, the idea of an organism involves something that is entirely self-contained, and in fact, one of the reasons we bring in the idea of an organism of something that causes itself to perpetuate its existence is to give us a clear distinction between an inside and an outside. Second, and as a result of this self-contained nature, the organism fits well with our first metaphor of the tree. If organisms have a well-defined distinction between inside and outside, then it makes sense to understand development through a unity giving rise to new forms, rather than from, for instance, the fusion of different principles.
Deleuze and Guattari’s Rhizome
When I introduced the account of the organism, I noted that it was often related to the idea of animals rather than plants. In this regard, it’s worth looking at the work of the 19th century philosopher, G. W. F. Hegel, who deals at length with both plants and animals. For Hegel, plants are understood along the same lines as animal organisms, but are less well defined, because the parts of plants don’t solely exist in terms of the whole, but can themselves be individuals. As such, they have a less ordered unity: ‘in short, any part of the plant can exist as a complete individual; this can never be the case with animals with the exception of the polyps and other quite undeveloped species of animals.’* In Hegel, therefore, there is a hierarchy of life, and since life follows the same pattern as intellectual thought, a hierarchy of thinking. The highest form is man, as the most unified, of the plants, the lowest form is the rhizome, which represents a breakdown of order:
[S]trawberries and a number of other plants, as we know, put out runners, i.e. creeping stalks which grow out of the root. These filaments or leaf-stalks form nodes (why not from ‘free portions’?); if these points touch the earth they, in turn, put out roots and produce new, complete plants.*
For Hegel, and the broader tradition, there is just one idea of organic thinking, and the rhizome is just understood as a lack of order. For Deleuze and Guattari, the rhizome is not a bad organic form, but instead is the model for an entirely different model of thought. Here, I just want to lay out three reasons why they hold the rhizome to be a proper alternative to traditional accounts.
First, if we look at the ‘arborescent’ model of thought, then we find that its self-sufficiency closes itself off from the outside, then its relation to the world is going to be one of representing, or imitating. Thinking on this model involves a kind of comparison, therefore, between two entities, thought and the world, that each are complete in themselves. While we can try to overcome this split, for Deleuze and Guattari, at the heart of the rhizome is a form that connects elements in diverse ways. There is no central ideal as to how the parts, or even which parts, are to be connected together. For Deleuze and Guattari, this implies a model of thinking whereby thinking is another element to be intertwined with the world, rather than an element that stands outside of it and reflects it.
Second, the kind of hierarchical model of thought we find with arborescence works fine for determining what something is, but it is limited to qualifying systems that already exist, rather than explaining where they come from. The arborescent model presupposes a central moment, the trunk, and show how this is differerentiated, and so cannot explain its constitution. For Deleuze and Guattari, there is no centre to the rhizome, and so we can explain how new systems become constituted through the assemblage of elements that differ from each other. As an example of the logic of the rhizome, we can introduce an archetypally rhizomatic system for Deleuze and Guattari: the wasp and the orchid. Deleuze and Guattari refer to the Ophyrs genus of orchids which attract wasps with a modified petal resembling a female wasp. As the male wasp attempts to copulate with the petal, pollinia become attached to its body:
The line or block of becoming that unites the wasp and the orchid produces a shared deterritorialization: of the wasp, in that it becomes a liberated piece of the orchid's reproductive system, but also of the orchid, in that it becomes the object of an orgasm in the wasp, also liberated from its own reproduction.*
Another example would be the origin of the eukaryotic cells that form the basis of all complex life. As Lynn Margulis shows, these cells emerge from a horizontal process of symbiosis, rather than from a process of qualification. That is, basic elements of the cell, such as mitochondria, migrated within the cell membranes of other cells in order to form mutually beneficial relationships: mitochondria allow the cell to use oxidising reactions to produce energy while the cell provides the machinery for the reproduction of the mitochondria. This idea of symbiosis leads to Deleuze and Guattari arguing for the replacement of a logic of being (A is B) with a logic of conjunction (‘and…and…and…’). The concern here is therefore with creation, rather than analysis, and just as the rhizome provides a model for the creation of systems, Deleuze and Guattari will understand philosophical thought as the creation of concepts.
The last point I want to talk about is teratology or monstrosity. If we accept the classical model of the organism, then what defines the unity of the organism is the function of the parts. This means that any deviation of the parts from optimal functioning can only be understood as a lack, or a fall into indeterminacy. We saw this in more general terms in with the rhizome itself, which could only be understood as a less determinate form of higher organisms. Traditionally, monstrosity involved a lack of determination, and relied on a distance from an ideal of proper functioning. Now, moving from understanding unity in terms of function to connection does not only mean that unity is always provisional, but it also means that changes in structure that disrupt its original function do not have to simply be seen as a process of degeneration. Rather, they are understood positively as a novel assemblage of parts. This is important because without this understanding of structure aside from purpose, we are unable to explain how the same part can play a different function in different organisms, and without this claim, we in turn cannot explain the transformation of species needed for evolution.
This isn’t the space to go into the rhizomatic model of thought in more detail, but taking the rhizome as a model allows us to move away from thought as a self-contained unit, to see it as a moment within the world that develops through encounters, and which opens onto a logic of conjunction and divergence. Such a logic reintroduces a moment of affirmation into those forms of life that are neglected by arborescent models of life, and opens the way to seeing such models themselves as epiphenomena of a deeper and more creative way of thinking.