Photograph by Jo Naylor.
APRIL 24, 2015
When our engagements with living beings rely on the language of “species,” they imperceptibly fall back into the categories of early Scholasticism. It is unclear to me why scientific ways of considering diverse forms of life have to stay frozen in that particular moment of European thought. They neither recall the Greek beginnings of the “systematic” investigations of nature nor catch up with the more recent developments in, say, quantum physics (or, closer to home, evolutionary theory). The outdated method of classifying plants, animals, fungi, etc. has a profound impact on our mode of seeing and treating them, which means that a change in how we order living beings would go a long way toward transforming our ontological and ethical relations to them.
The writings of “the last Roman and the first Scholastic,” Boethius, are especially pertinent to what I refer to as “species-thought.” Through induction from “singular things,” Boethius claims, it is possible to arrive at their likeness (similitudo), which is the foundation for the concept of species: “…a species should be considered as nothing other than a thought (cogitatio) collected from the substantial likeness of many individuals which differ by number, whilst a genus is a thought collected from the likeness of species” (2InIsag. 166:16-18). From the standpoint of an already formed species-thought, however, the differences among the individuals that comprise it are accidental and superficial, just as from the perspective of the genus the distinctions among the species are inessential. To continue working with the notions of species, genera, and kingdoms (note how the latter superimpose a monarchical structure on modes of living) is to capitulate before the power of abstraction, oblivious to singularity. Even if we stress the multiplicity of such categories, they will remain shackled to the actual or potential unity of a higher-level universal. It is as though we first placed living beings in hermetically sealed boxes, and then tried to air these containers by cutting windows, through which they could communicate with each other and with the world.
In broad brushstrokes, the heavy Scholastic heritage is the background for the reception of the philosophies of plant and animal life developed today. I am often asked, tongue-in-cheek: “You concentrate on plants. But what about fungi-thinking? Or algae-thinking? Or even mineral-thinking? Why exclude these other categories of organic and inorganic entities?” These questions are misguided, because they presuppose that I subscribe to the Scholastic division of the world into species, genera, and so forth.
Actually, “plant-thinking” has little in common with “species-thought.” Although it might seem that I privilege the biological Kingdom Plantae, I do not intend it as a reference to some generic, abstract, nonexistent being that would encompass tulips, sequoias, and moss. Rather, “plants” stand for a tendency of living and thinking that promotes growth, decay and metamorphosis. This vital tendency, vector, or trajectory cuts across Boethius’s “substantial likeness” and difference among individuals, and pertains to various kingdoms, classes, orders, families, and so on. That is why there is nothing odd in recognizing and cultivating “the plant in us,” which is to say, the vegetal trajectory that certain aspects of our lives follow. And that is also why I can maintain that plants are radically other, to the extent that our habitual ways of being in the world and tendencies of living diverge in some respects (e.g., humans are not sessile beings, with all the implications of this fact for our uprooted growth).
Attentive readers will notice that I emphasize thinking, and not thought, because my point of departure is not the substantial similitude of comparable objects but the differentials, at times approaching zero, between living vectors, including “inside” ourselves. The frozen molds of thought correspond to equally static realities they capture, determine, and define, separating these realities from all the others with the help of something like conceptual walls. Conversely, thinking befits the dynamic ontological tendencies that have been for too long contained within the strictures of categories, above all, those of species and genera. Perhaps, “befits” is not the right word here, since the living vectors I have invoked are, at one and the same time, the trajectories of material, spatialized, extended, constantly metamorphosing thinking. Ironically, I may end up re-confirming the insight of Parmenides, typically associated with a static and inflexible ontology, that it is the same thing to be and to think. Indeed, outside the horizons of species-thought, there is virtually no difference between “plant” (being) and “thinking”: plants think, strive or tend toward…, while thinking plants, grows, changes, decays.
For all the innovations of his process philosophy, Alfred North Whitehead was wrong to ascribe, in retrospect, Scholastic categories to Aristotle: “Aristotle’s science of classification into genera, and species, and sub-species is the science of mutually exclusive classification. It develops Plato’s suggestion of a science of ‘Division’.” Greek classifications were, precisely, not mutually exclusive, to the extent that, failing to live up to their end or telos, certain “higher” beings could become quite indistinguishable from the “lower” ones. This is what happens in Aristotle’s Metaphysics, according to which, if humans disobey the precepts of formal logic—notably, the principle of non-contradiction—they become plant-like. Against relativism avant la lettre, Aristotle writes: “If, however, all men alike are both right and wrong, no one can say anything meaningful; for one must then at the same time say these and also other things. And he who means nothing, but equally thinks and does not think, in what respect does his condition differ from that of a plant?” (1008b). Negatively and with disdain, then, he outlines plant-thinking in the converging trajectories of the human and the plant outside formal-logical parameters. There is nothing “mutually exclusive” about the layers of vitality Aristotle terms psukhē (“soul”) predicated upon one another; as I note in my The Philosopher’s Plant: An Intellectual Herbarium, its vegetal configuration “traverses biological kingdoms and species.” Strip the human stratum of “rational thought” and you will discover a humanoid plant, someone who or that, equally thinking and not thinking, merely vegetates—he implies with some irony. In my view, this is the groundwork of plant-thinking, which has little to do with the logic of species and kingdoms.
From there, the alternative to species-thought winds through Plotinus’s “growth-thought”, Avicenna’s love, Spinoza’s modes, Leibniz’s expression, Schelling’s “minimal irritability”, Bergson’s torpor with the possibility of sudden awakening… But it is always to plants that this other thinking returns, drawing inspiration from their proliferation that disregards all barriers (whether made of physical concrete or of concepts) and that transcends even the opposition between total immanence and pure transcendence.
 Alfred North Whitehead, Adventures of Ideas (New York: The Free Press, 1933), pp. 137-8.
 Michael Marder, The Philosopher’s Plant: An Intellectual Herbarium (Columbia University Press, 2014), p. 31.