Moss: The Inassimilable


Michael Marder


In July 2018, desperate to escape from unbearable summer heat, I went with my then two-year-old son on an impromptu week-long vacation in the region of Sintra, just outside of Lisbon, Portugal. Sintra is a lush mountainous area, very close to the westernmost point of continental Europe, an area boasting its own humid and cool microclimate. During the long walks along winding forest paths and small mountain roads, my son immediately learned a new word he would often repeat throughout our stay in Sintra and thereafter: moss. Indeed, moss was everywhere, covering with a thick carpet roadside stone fences, tree trunks and boulders scattered on the forest floor. Touching its humid green softness with an open palm of his hand, my son would savor as much the experience as the word, repeating the gesture and uttering it over and over. I am convinced that, in his mind, the entire place was linked to the ubiquitous tiny plant he had encountered for the first time there.

Such fascination is foreign to philosophers who, habitually neglecting plants, pay no attention whatsoever to the smallest among them. Plant nature in general and mosses in particular are beneath them, those lofty thinkers refusing to bend, to stoop, physically or spiritually, as low as that. One salient exception is Jean-Jacques Rousseau, quipping in his Reveries of a Solitary Walker: “They say a German once wrote a book about a lemon-skin. I could have written one about every grass in the meadows, every moss in the woods, every lichen covering the rocks—and I didn’t want to leave even one blade of grass or atom of vegetation without a full and detailed description.”[i] Behind the most careful naturalistic observations and reflections, we do not find the ideal of scholarly detachment, but passionate commitment, a child’s wonder and curiosity preserved throughout one’s life and triggered, precisely, by “every grass in the meadows, every moss in the woods, every lichen covering the rocks.” It is an excess of enthusiasm that borders on the impossible: to describe the tiniest bit, every “atom of vegetation,” incorporating it into an overarching project of writing, or rewriting, the world.

The father of modern scientific method aspiring to smash the so-called idols of the mind, Francis Bacon did study mosses, which, together with mushrooms, he considered to be “imperfect plants.”[ii] If his studies are interesting, they are so not for what they reveal about moss, but, on the contrary, for what they say by omission and despite themselves, as though unconsciously. For example, Bacon insists that the “moss of trees is a kind of hair; for it is the juice of the tree that is excerned, and doth not assimilate.”[iii] Obviously, he forgets that moss can grow on trees as well as on rocks, where the theory that it consists of the exuded and unassimilated “juice” of a host plant makes no sense whatsoever. Still, in this glaring oversight, there is a glimmer of insight, an inadvertent admission that moss, as this unique plant and as a condensation of the flora in the miniature, is inassimilable for metaphysical thought. It is this relation of the inassimilable that I want to explore with you in today’s remarks.

According to Bacon’s theory of juicy exudence, older plants grow more moss because their vigor is diminished, their sap unable to permeate the entire tree: “Old trees are more mossy far than young; for that the sap is not so frank as to rise all to the boughs, but tireth by the way and put out moss.”[iv] The emergence of moss is linked to stagnation, the diminished quality of plant metabolism that results in the exteriorization of the inassimilable portion of tree sap.

Bacon is, in fact, not alone in thinking that moss is a sign of decline in vegetal vigor. St. Hildegard of Bingen writes in her Physica: “When trees grow old, they begin to lose their inner greenness (viriditas), and if they are not young, they send the greenness and health, which they ought to have inside, to the exterior bark. Thus, moss grows on the bark because these trees do not have inner greenness.”[v] Moss prompts a spatial confusion between what is (or should be) inside and what is (or should be) outside: it literally turns vigor inside out, implanted on the bark instead of circulating in the tree. While consisting of “greenness and health,” it expresses their weakening in the host. More than that, neither Bacon nor Hildegard before him acknowledge the host as host, since they do not see in moss a parasitic plant living on a plant of another species. The view of moss as inassimilable hides the gap between the same and the other, actually assimilating the symbiont to the host.

Colloquially speaking, “gathering moss” is growing old. As an old Latin proverb goes, “A rolling stone gathers no moss [Saxum volutum non obducitur musco].” While, in its initial sense, the dictum criticized those who, rootless and roaming the earth, assumed no responsibilities, according to a modern interpretation (picked up by Bob Dylan and the British rock bank “The Rolling Stones”), it meant that, being in constant motion, one escaped the states of stagnation and senescence. The historical shift in the interpretation of the proverb is telling. For the ancients, the contrast is not between rest and motion, but between kinds of movement: the purely mechanical, relatively fast displacement of a stone, on the one hand, and the self-directed, relatively slow movement of vegetal growth, on the other. And this is not to mention that, with varying degrees of approval, the proverb describes a situation, where strict dividing lines are maintained between the inorganic realm and the organicity of moss. A rolling stone refuses the community—indeed, an entire world—moss could have created on its surface. Still, moss remains inassimilable to a narrow vision of movement and within an order built on the need to compartmentalize various kinds of being, if not segregate them from one another.   

Perhaps the most remarkable piece of evidence for how inassimilable moss is to metaphysical thought is its unique temporality. Just as it confounds the distinction between the inside and the outside with regard to vitality, so it muddles the difference between youth and old age, the before and the after of vegetal life. With moss, the bookends of plant history close into a circle: “the most primitive of land plants,”[vi] one of the vegetal pioneers preparing the ground for future growth,[vii] it thrives on nearly lifeless or entirely dead trees. Softening not only the sharp outlines of rocks and leafless branches but also the edges of time—those abruptly dropping cliffs of the beginning and the end—, moss escapes the power of linear chronologies and hierarchies. Anarchic, it performs the work of time, grinding down the rocks, speeding up the decay of fallen tree trunks, metabolizing mineral and vegetal matter. As Robin Wall Kimmerer puts it: “The rocks are beyond slow, beyond strong, and yet yielding to a soft green breath as powerful as a glacier, the mosses wearing away their surfaces, grain by grain bringing them slowly back to sand. There is an ancient conversation going on between mosses and rocks, poetry to be sure.”[viii] I would add that the conversation, too, is beyond ancient: it is that of time itself.

Why is our conceptualization of time, drawing on metaphysical order and stability, ineffectual when it comes to the time of moss? First, as we have seen, the relative terms “young” and “old,” “before” and “after,” are inapplicable there where a linear chronology breaks down. Second, the paradigm of energy gradually dissipating in the measure of distancing from an energetically rich beginning no longer works: diminished vitality coincides with the exuberance of mossy vegetal life, one that infinitely mirrors and is mirrored in “the architecture of the surrounding forest.”[ix] Third, though “primitive,” moss encompasses at least 14,000 species and includes virtually all methods of plant reproduction (be they sexual or asexual) and growth, reliant on mutual interactions with the boundary layer. Hence, already in the nineteenth-century a relevant entry in The Edinburgh Encyclopedia stated: “He who could examine the nutrition, the growth, the regular confirmation, the provision made for the continuation of the species…of even the minutes Phascum [mosses], without perceiving in them proofs of intelligence, power, and goodness, would probably receive no more conviction from the sublimest truths that astronomy can unfold.”[x] Finally, moss grinds rocks to sand and builds up the soil for future plant growth; it performs simultaneously the tasks of analysis and synthesis, complicating the image of time as a universal destroyer, the merciless devourer of all without exception.

As for the philosophers’ relation to moss, it would be fair to conclude that, even in the best of cases, this plant remains inassimilable to their thought, which it nonetheless stimulates and props up from the outside. Let’s refer to Rousseau once again and pair him with Nietzsche’s Zarathustra. The Genevan philosopher recalls reaching a patch of wilderness in the mountains of the Môtiers region, which left him speechless. “Gradually succumbing to the powerful impression of my surroundings,” he relates, “I forgot about botany and plants, sat down on pillows of lycopodium and mosses, and began dreaming to my heart’s content, imagining that I was in a sanctuary unknown to the whole universe.”[xi]

Besides furnishing a pillow that supports Rousseau’s body, mosses are the strange plants that make him “forget about botany and plants.” What sort of oblivion is that? I think that the pairing of the forgotten plants with botany is revealing: Rousseau cleanses from his mind plants as objects of botanical study, arranged in systems of strict classification. The “sanctuary unknown” he imagines himself in is another relation to vegetal life not mediated by such scientific constructs. The dreamy state Rousseau immerses himself in—the state that marks his reveries—is that of a forgetting that ultimately recalls something else outside the sphere of conscious representation, namely a togetherness with plants. Plunging into the deep reserves of the unconscious, he reconnects with the sources, whence his philosophy springs. And all that is occasioned by moss that, despite not having roots (it only has rhizoids), despite not burrowing deep into the dark of the earth, which could epitomize the unconscious, induces rapture and claims for itself the philosopher, body and soul—the body seated on its soft pillows and the soul enduring under the sway of its powerful impressions.

Nietzsche’s Zarathustra also dreams (and, indeed, sleeps) on moss. He lies down on a bed of moss under a tree in a period of transition, when he realizes that he needs living companions, not dead ones: “Zarathustra found himself in a deep forest, and he did not see a path anywhere. So he laid the dead man into a hollow tree—for he wanted to protect him from the wolves—and he himself lay down on the ground and the moss, his head under the tree. And soon he fell asleep, his body weary but his soul unmoved.”[xii] Rousseau sat on pillows of moss; for Zarathustra, mossy ground becomes the support for his prone body, his head slotted between plants: the moss below him and the tree above. Without a path in the dark of a forest, Zarathustra finds a way in his own unconscious, in sleep facilitated by moss. Waking up rejuvenated, he utters his famous speech, addressing the living and refusing to speak to and for the dead. From below, moss bolsters and refreshes his thought and his relation to life, producing an effect that is diametrically opposed to the loss of vigor, with which it had been associated. Inassimilable, mentioned but in passing in the narrative of Zarathustra’s sleep and awakening, moss secretly prepares the moment of high noon, of another enlightenment and the shortest shadows.

To return to Sintra and to my son’s first experience with moss, what was stunning (albeit in line with the way children tend to think) was that he applied this word he had just learned to the place where he first encountered it, to all tiny plants, to the trimmed grass of lawns, to lichens… And so, in his mind, moss became easily assimilated and extended to the category small growing things. We should note, however, that it was in this way assimilable to a world seen through a child’s eyes, which is, precisely, the world inassimilable to the proud and self-sufficient adult experience of those who, at Kant’s urging, should emerge from their “self-incurred immaturity.” The category small growing things is given a certain shape, figured as moss. Its concrete universality, to resort to Hegel’s terms, is highly significant, above all as an alternative manner of approaching plant life. (I must note that, although Hegel treats moss as universal vegetation in his Philosophy of Nature, he considers it to be an indeterminate universal.)

In their turn, Rousseau’s reveries and the enlightenment of Nietzsche’s Zarathustra try to recover a child’s wonder, the point of view that, in this case, identifies with and recognizes itself in small growing things. Instead of advocating on behalf of adult seriousness, one should appeal to that immaturity which is of a piece with the promise of life, with life’s own essential unripeness and playful puerility. Within that jovial scheme, calling all small growing things moss is not lumping them together into one and the same conceptual basket; rather, it is giving something like a proper name to a category, rendered singular thanks to this name. The apparent disorder among levels of generality that ensues is, actually, a different order, attentive to moss’s inassimilability, its irreducibility to the taxonomic division (or the phylum) Bryophyta within the kingdom Plantae.

We say that things gather moss when they grow old, unless they—like a rolling stone—maintain themselves in motion. But here it is moss that gathers beings regardless of their formal classifications and, overcoming the segregation ingrained right into our “mature” cognition, rejuvenates thinking. This is what I discovered in Sintra with my son’s help. This is what I rediscovered in Rousseau and Nietzsche. And this is what I keep finding out in my forays into the philosophy of vegetal life.



[i] Jean-Jacques Rousseau, Reveries of a Solitary Walker (London & New York: Penguin, 1979), p. 84.

[ii] Francis Bacon, Philosophical Works, edited by James Spedding et al. Volume IV (Boston: Brown & Taggard, 1862), p.  407.

[iii] Bacon, Philosophical Works, p. 406.

[iv] Bacon, Philosophical Works, p. 405.

[v] Hildegard von Bingen, Physica, translated by Priscilla Throop (Rochester, VT: Healing Arts Press, 1998), p. 133.

[vi] Robin Wall Kimmerer, Gathering Moss: A Natural and Cultural History of Mosses (Corvallis: Oregon State University Press, 2003), p. 13

[vii] Robert M. Stark, A Popular History of British Mosses (London: Lovell Reeve, 1852), p. 4.

[viii] Kimmerer, Gathering Moss, p. 5.

[ix] Kimmerer, Gathering Moss, p. 10.

[x] “Musci,” The Edinburgh Encyclopaedia, First American Edition, edited by David Brewster, Volume XIV (Philadelphia: Joseph & Edward Parker, 1832), p. 2.

[xi] Rousseau, Reveries, p. 118.

[xii] Friedrich Nietzsche, “Thus Spoke Zarathustra,” in Portable Nietzsche, edited by Walter Kaufmann (New York & London: Penguin Books, 1988), p. 135.

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