Affect theory offers a new means of understanding nature poetry, particularly in the romantic vein.  Here, of course, the term romantic does not pertain to love poetry, but to poetry of the early nineteenth century, which was romantic in the broader sense that it viewed experience itself as potentially passionate.  Specifically, in this context, passion does not refer so much to powerful emotions, or to powerful feelings of desire, as to a material flow of sensation related to the etymological root, pati, suffer.   What I am calling passion or suffering here, Whitehead called “feeling,” which he explained in terms of a process of “prehension” by which all apparent “particulars” emerged out of a process of mutual registering. Deleuze preferred the word affect to passion, precisely because affect is more clearly prepersonal.  This notion of passion or affect of course comes right up against the deep bias of orthodox western epistemology.
Although western philosophers in the “counter-philosophical” tradition (Spinoza, Bergson, Whitehead, Deleuze) have challenged this bias, we may need further cross-cultural dialogue with eastern thought (particularly Indo-Tibetan buddhist philosophy) to get the to the heart of this issue.  One thing eastern philosophy might remind us, with keen precision, is that it is only through a conceptual lens that we “reify” phenomena, or ‘know’ them in terms of solitary objects.  Whitehead famously called this the “fallacy of misplaced concreteness.” Until recently, with the work of various philosophers inspired by Deleuze’s “counter-philosophy” and Whithead’s “process philosophy” (Massumi, Shaviro, Bennett, Braidotti, Stengers), we were not much in the habit of thinking about the relationship of mind and matter in this way.  What is radical about this new current in philosophy is the understanding of matter, which perhaps could not be better expressed than by Whitehead, who argued that the problem in western philosophy had been its notion of the particular:
All modern philosophy hinges around the difficulty of describing the world in terms of subject and predicate, substance and quality, particular and universal… We find ourselves in a buzzing world, amid a democracy of fellow creatures; whereas, under some disguise or other, orthodox philosophy can only introduce us to solitary substances, each enjoying an illusory experience: “O Bottom, thou art changed! what do I see on thee?
The true point of divergence is the false notion suggested by the contrast between the natural meanings of the words ‘particular’ and ‘universal’.  The ‘particular’ is thus conceived as being just its individual self with no necessary relevance to any other particular…. The principle of universal relativity directly traverses Aristotle’s dictum, ‘A substance is not present in a subject’.  On the contrary, according to this principle an actual entity is present in other actual entities.  In fact if we allow for degrees of relevance, and for negligible relevance, we must say that every actual entity is present in every other actual entity.  The philosophy of organism is mainly devoted to the task of making clear the notion of ‘being present in another entity’.
(Process and Reality, 50, emphasis added)
Although Whitehead held Spinoza to be something of a monist, and personally tried to avoid the monist position (and its attendant danger of what Bruno Latour has described as “panpsychism”) by giving a special place to “eternal objects” or to mental realities that cannot be collapsed into material processes, there seems to be a remarkable similarity between Whitehead’s account of prehension and Spinoza’s account of affect.  This similarity is most evident in Deleuze’s explication of Spinoza’s notion of imagination.  Deleuze attacked the problem of traditional epistemology: the assumption that the “image of thought” is unproblematic and nonviolent.  He called instead for thought without an image, or for imagination as it was understood by Spinoza and by the British Romantics.  Spinoza’s ethics, though it speaks of power and action, actually involves a kind of negative, virtual, counterepistemological aesthetics. What could be more foreign, heretical, or humiliating to the human than Spinoza’s account of imagination as the awareness of “external bodies as present in us” (The Deleuze Connections 23) or his notion  that to imagine is to be subject to the “immanence of other powers in the compositions of ourselves” (The Deleuze Connections 28)?
Spinoza’s radical challenge to Descartes was based on a similar objection to the Cartesian emphasis on the circumscribed knower as a category distinct from material process.  When Whitehead pinpoints the notion of the particular as the key problem in western philosophy, he is likewise articulating a driving insight into reification or “the fallacy of misplaced concreteness.”  The problem that arises with Descartes is what Whitehead diagnoses (in reference to orthodox western philosophy) as the “presupposition of the mind with its private ideas” (76).  Against this representational model of cognition, and its attendant epistemological problem of the “gap between idea representing and ‘actual entity represented'” (76), Whitehead asserts the existence of an “extensive continuum” as a plenum of mutual interrelations:
But if we take the doctrine of objectification seriously, the extensive continuum at once becomes the primary factor in objectification.  It provides the general scheme of extensive perspective which is exhibited in all the mutual objectifications by which actual entities prehend each other.   Thus in itself, the extensive continuum is a scheme of real potentiality which must find exemplification in the mutual prehension of all actual entities.
(Process and Reality 76)
Like Kant, Whitehead views matter as a plenum, but Kant promptly isolates cognition from this plenum, placing the subject at the center of the experience of the world, whereas Whitehead understands this plenum interrelationally, as the field or nexus of mutual prehensions out of which subjects emerge.  In Whitehead, subjects emerge out of the world, the world does not emerge out of the subject. In other words, Whitehead’s model of experience is thoroughly embodied and participatory.  His principle is interconnectedness, which thoroughly undermines any notion of the “mind with its private ideas” or of abstract, disembodied, private experience. In brief, in challenging the western account of particulars (as “solitary substances”), Whitehead challenges a western “orthodoxy” that precludes our recognition that nothing exists independently, or that everything exists interrelationally or interdependently.  As he observes: “…under some disguise or other, orthodox philosophy can only introduce us to solitary substances” (50).
     With affect theory, we begin to think through, in a serious manner, the implications of matter that is not atomistic.  We begin to consider what it means if the things we designate as concrete particulars are in fact interfused or interrelated with an infinite nexus of things. On this basis, Whitehead relabeled persons as “actual entities,” to place persons within the same category as all existing things, or everything that becomes concretized in the creative process of mutual prehensions.  Affect theory, particularly as Deleuze articulated it, and as Massumi has further explicated, speaks of affects or passions as prepersonal intensities or flows of experience that precede the selective and eliminative action of consciousness.  In regard to terminology, Deleuze preferred the word “affects” to “passions” precisely because the latter term carries connotations of personal emotion, or feeling tied to personal experience.  Affect theory, in this light, explains persons as the foreclosure of affects (I prefer to say, of passions).  That is, passions precede persons.  Hypothetically, then, there should be the possibility of a lessening of the person at the threshold of vibrant matter or unqualified affect.  Studies of Emily Dickinson, such as Anne Lise Francois’s Open Secrets and Katie Peterson’s Supposed Person: Emily Dickinson and the Selflessness of Poetry have emphasized exactly this “lessening” or attenuation of the bounded self or discrete knower.  Implied in these studies is a sense of participation in the material universe that literary criticism has difficulty registering.  After all, it describes the romantic attitude par excellence.
To suggest that experience is passionate was, for the romantics, to suggest that somehow when one allows oneself to experience some aspect of the world, one actually participates in its reality.  This can either be taken as an expression of delusional grandiosity or as an expression of humility.  One can read it as an inflated claim to special knowledge through some “more than ordinary organic sensibility” or as a report of what happens when one reduces one’s claims to knowledge.  For example, for the poet watching the wind move through the trees or the clouds sweep across the sky, the act of attention is not simply a visual or optical experience, in which one ‘knows’ the world through an optical image, but is also a haptic experience, pervaded with touch or contact.  Attention, then, is not simply mental (in the more proscriptive sense of the word) but is also embodied.  Wordsworth, as I will explore further, called this the “excursive” quality of the mind, and described the highest potential of this kind of attention as “interfusion.”
[NOTE: Arguably, when Wordsworth attributes this power to the mind,one can take him for an idealist.  As Karl Kroeber argues in one of the earliest works of ecological literary criticism (aptly titled Ecological Literary Criticism: Romantic Imagining and the Biology of Mind), both the Yale School critics and the New Historicists did exactly that: they read Wordsworth as a poet of the mind in transcendence of mundane nature.  And while, admittedly, the Wordsworth of the immortality ode is different in significant ways from the Wordsworth of the 1805 Prelude, to the extent that Wordsworth does write of interfusion, some sort of embodied experience seems deeply implied.  That is, if the mind goes ‘out’ into an experience of natura naturans or naturing nature, then the mind is coming into contact with some sort of active process of reality. From a twenty-first century perspective, it seems reasonable to think about “naturing nature” in terms of the active interrelationality of material processes.  This brings us right up against the crucial terms: matter and mind.  How can the mind go out and meet matter? If we take these two as fundamentally independent of one another to begin with, there is a real problem.  However, what happens when we rethink matter less in terms of concrete and discrete units of existence and more in terms of fluid interrelations?  In Wordsworth, the mind is profoundly affected by these living interrelations, which impress it with ‘sympathies’. Over and over, his salient theme is that mind steeped in these experiences of interrelation will suffer less from a sense of isolated existence.  Such a mind will be infused with the primordial principle of relationship, and hence less selfish].
From a common sense point of view, most of us will agree that experience does seem to be embodied.  When we walk through a woods, we receive impressions that seem to act upon our sympathies.  We feel that we participate in the reality of those woods, and the more romantic among us may feel that we actually receive a quality of peace or harmony from those woods.  However, we may be reluctant to describe our experience as interfusion, if only because it involved a general sense of participation, but nothing so intense as interfusion.
Sympathy, as I will discuss, is the key term.  To what extent do we believe that knowledge and experience involve sympathy?  Various philosophers of the long eighteenth century articulated models of experience that effectively foreclosed sympathy.  Locke’s empiricism, for instance, is based on an atomistic theory of sense experience that seems better attuned to a world of discrete objects than of relations, although Whitehead goes to lengths in Process and Reality to remind us that Locke was well aware that relations or ‘powers’ obviously do underlie the things we refer to as objects.  Kant’s transcendental idealism treats material reality as a plenum or as a bristling manifold, but promptly seals human cognition off from potential sympathies with “vibrant matter” (Bennett).  For example, Kant’s account of the aesthetic of the beautiful de-emphasizes the object of sense-experience and gives primacy to the “free play” of cognition.  That is, the object of aesthetic experience is only interesting to the extent that it escapes easy qualification by the faculty of understanding.  Thus, as the processes of mental representation fail to find a suitable image or concept for the object, the faculty of intuition (sense experience) and of understanding (representation) are set into a curiously irresolvable play or dialogue.  For Kant, the stimulating strangeness of an experience of beauty has less to do, then, with the qualities of the aesthetic object, than with the mind’s experience of its own cognitive processes. The same proves true in Kant’s account of the aesthetic of the sublime: in the failure of the mind’s processes of representation (due to the apparent lack of finite form in an object such as an immense mountain), the mind gains a glimpse of higher, more mathematical processes that nevertheless provide continuity to cognition.
Hence, while Kant describes material reality as active, vibrant, and indeterminate, his emphasis falls exclusively on a priori universal forms of cognition that convert ‘mere conditioning’ sense experience into human experience.  The primacy he gives to this form-giving capacity of the mind becomes most evident when he explains that moral choice is free precisely because it is not determined by ‘pathological’ or merely passive conditioning sensuous experience.
The questioned to be raised in affect theory is perhaps best introduced by Alfred North Whitehead’s proposition that “consciousness presupposes experience, and not experience consciousness.  It is a special element in the subjective forms of some feelings” (Process and Reality 53).  Whitehead offered particularly incisive critique of empiricism as it emerged from Locke, arguing that “Locke inherited the dualistic separation of mind from body.  If he had started with the one fundamental notion of an actual entity, the complex of ideas disclosed in consciousness would have at once turned into the complex constitution of the actual entity disclosed in its own consciousness, so far as it is conscious – fitfully, partially, or not at all” (53).  Indeed, Whitehead challenges the implicit empiricist tenet, most prominent in Adam Smith, that experience is private, because sense data impinge upon a particular mind.  Whitehead dismisses this private theater of atomistic experience as “sensationalist mythology” (141) arguing that feeling and sensation cannot be collapsed this way: “The confinement of our prehension of other actual entities to the mediation of private sensations is pure myth.  The converse doctrine is nearer the truth: the more primitive mode of objectification is via emotional tone, and only in exceptional organisms does objectification, via sensation, supervene with any effectiveness” (141).  As I read Whitehead, he is making a distinction between atomistic sensation and what elsewhere he calls “sensitive reactions” (16). Prehension (or the process of coming to know another entity – “objectification” – through sensitive feeling, mutual modification, or relational experience) thus does not involve “sensation” (the private registering of discrete sense-data) so much as feeling; only sensation in the sense of the highest form of sensitivity to detail and difference (one might think of Wordsworth) enhances feeling or the process of experience.
Ecophilosopher Adrian Ivakhiv offers a gloss that explains the primacy of “mental ecology” in Whitehead, or of the idea that the world is “perceptive and communicative in nature” and that the universe is “fundamentally active and communicative—experience all the way down,” thus tying Whitehead to other “counter-philosophers” (Bergson, Bates, Deleuze, Guattari):

When things encounter each other, there is an exchange between them, a response or ripple that is affective or “emotional” in nature (as Whitehead argued) and that has to do with a “taking account of,” a meaning- making and responding to what is encountered. Between the social and the material, then, is the intermediary register of the mental-perceptual. The idea of a mental ecology is intended to suggest that we humans are embodied agents and interpreters of a world that is not only there to be perceived, but also perceptive and communicative in its nature. Perception or mind, understood as the sense- and world-making capacity intrinsic to all experience, is the interactive dimension through which a world comes into being for world- bearing beings… An environment is itself comprised of perceptual and communicative relations; from this, it follows that perceptual ecologies constitute the interactive milieu within which the material or “objective” becomes the social and “subjective,” and vice versa. That milieu is where sensations and sensory organs, bodies and desires, social groups and mediating formations become connected in specific ways. Perceptual ecologies are the interrelations that arise in the zone between things, the space that Maurice Merleau-Ponty described as the fleshy, interpenetrating chiasmus of self and world. They are the spaces of “contagion, contamination and inspiration,” as Connolly and Bennett put it, where force and affect flow “across bodies” and are communicated “by looks, hits, caresses, gestures, the bunching of muscles in the neck and flushes of the skin.” If we follow the processual ontology suggested by Whitehead, Deleuze, Bergson, and others, and take the uni- verse to be fundamentally active and communicative—experience all the way down—then it is precisely this mental ecology that is central to things, and it is through perceptual experience that subjects and objects, and thus a subject- world and an object-world, are possible at all. 

(Ivakhiv, 34-6, emphasis added)