Leibniz’s Blades of Grass: The Philosophy of Plants, Difference as the Wellspring of Identity, and How Diversity Gives Meaning to the World
By Maria Popova
Nearly a century before Walt Whitman led us to see that “a leaf of grass is no less than the journey work of the stars,” Immanuel Kant proclaimed that there will never be a Newton for a blade of grass. There may not be a Newton, but there is a Leibniz.
One otherwise ordinary day in 1685, the lavish lawn of Princess Sophia’s palace in Hanover was strewn with the extraordinary sight of frocked, corseted, and coiffed aristocrats bending and kneeling and squinting at the grass, secretly relishing the childlike wonder beneath the grand grownup experiment they were conducting — the quest to find two identical leaves of grass in order to refute one of the seven fundamental ontological principles laid out by the German polymath Gottfried Wilhelm Leibniz (July 1, 1646–November 14, 1716): the identity of indescribables, simply known as Leibniz’s Law, stating that there can be no two separate entities that have all their properties in common. A gentleman in the party had taken issue with Leibniz’s principle in the Princess’s presence, upon which she had simply challenged him to refute it by finding two blades of grass exactly alike.
Leibniz, who a decade earlier had developed calculus independently from Newton, watched with satisfaction as the gentleman “ran all over the garden for a long time” before finally giving up. This comical collision of empiricism and logic furnished one of the pillars of Western philosophy, fomenting our disquieting sense that however eagerly we may press our minds against physical reality, however eagerly we may lance our fingertips on its blade, we live mostly in a consensual imagined reality of abstractions. A year after the garden experiment, Leibniz himself affirmed this insight in an essay he titled “Primary Truths”:
Never do we find two eggs or two leaves or two blades of grass in a garden that are perfectly similar. And thus, perfect similarity is found only in incomplete and abstract notions.
A decade after philosophers Lorraine Daston and Gregg Mitman’s excellent inquiry into how we think with animals and a generation after John Berger’s landmark meditation on how looking at animals clarifies us to ourselves, philosopher Michael Marder explores how we clarify our own minds by looking at and thinking with plants in The Philosopher’s Plant: An Intellectual Herbarium (public library). Reaching into the grass to wrest from it Leibniz’s broader “protest against the pretentious universal perspective without perspective that goes under the name of objectivity,” he examines the most elemental questions of individuality, incompleteness, diversity, and difference that color every aspect of our lives:
Only mathematical or geometrical notions differ in magnitude and in no other respect; matter, on the other hand, presupposes a predifferentiation and non-numeric determination well in advance of its concretization in things. At the threshold of the modern era, the garden is converted into the arena of valiant philosophical resistance to the mathematization of the world, where everything can be assigned its corresponding quantitative value on a uniform spatiotemporal grid of coordinates. And plants, despite being historically understood as incomplete or deficient things, are at the forefront of this struggle against the incompleteness of philosophical and mathematical abstractions.
Because Leibniz honored the absolute individuality of each blade of grass, and because he recognized that what makes it distinct from every other blade of grass is the particular location and confluence of conditions in which it grew, at the root of his principle is a bold defiance of John Locke’s model of the soul as a blank slate. Marder writes:
Acceptance of the conclusion that “no two individual things could be perfectly alike,” he argues, “puts an end to the blank tablets of the soul, a soul without thought, a substance without action, empty space, atoms, and even to portions of matter which are not actually divided,” among other things. The Leibnizian universe, much like his writing, resembles a Baroque garden or a Baroque painting, wherein space is saturated to the maximum, in an intricate imitation of vegetal excess. Emptiness and nondifferentiation — the mind as a blank slate — have no place there; their true home is the sterile sphere of mathematics and of modernity’s desire to force reality into quantitative molds.
Marder considers the blade of grass as the particular fulcrum for Leibniz’s ideas, its particularity itself significant, and proposes a branch of phenomenology specifically derived from the contemplation of vegetable life: phytophenomenology. In a passage evocative of the late, great physicist Freeman Dyson’s insistence that diversity is the ruling law of the universe, Marder explains:
Phytophenomenology may be encapsulated in the thesis that plants have their own take on life and on the world, their growth and reproduction being the lived and enacted processes of interpretation… Each species has its unique perspective, as does each individual specimen comprising the species and each part of any given plant. The difference between two blades of grass boils down to a divergence, however negligible, between embodied orientations to and lived interpretations of the environment. The world, moreover, is nothing outside of a nonmathematical sum, or a confluence of these differences. Assuming that two blades of grass were completely identical, they would have represented one perspective, one life, one piece of being, one blade of grass… In that case, the world would be poorer — or, better yet, it would not be — since it flourishes only in and as the variance among the beings that comprise it. Difference is at the origin of the world: it “worlds.”
Even two nearly identical (though not quite!) blades of grass present two faces of the world; they are the actual variations on the theme of a possible blade of grass, which, in and of itself, is abstract and incomplete, lacking in realization. The backbone of Leibniz’s monadology is this wedge of difference, responsible for the separation among perspectives on the world… Each blade of grass has its sufficient reason, elucidating the necessity of its existence just the way it is, despite the inexhaustible array of possibilities for it being otherwise.
Complement The Philosopher’s Plant: An Intellectual Herbarium, an intellectually coruscating and thoroughly original read in its entirety, with The Moral of Flowers — 19th-century poet and painter Rebecca Hey’s illustrated encyclopedia of poetic philosophies from the garden — then revisit the astonishing contemporary science of what trees feel and how they communicate.
Published June 18, 2020