A Picture of Mind
How in the most general terms should we characterize the mind, animal or human? If the body has a respiratory system, a digestive system, and a reproductive system, what systems does the mind have? How does it divide up? What is its fundamental structure? I suggest the following tripartite picture: intelligence, desire, and will. These are the basic compartments of the mind: cognition, conation, and volition. Cognition includes the senses and what is traditionally called Reason; conation includes need, appetite, and wish; volition includes action, decision, and intention. I would say, further, that intelligence is manifested in the form of knowledge, desire is manifested in the form of emotion, and will is manifested in the form of action. What knowledge is to intelligence emotion is to desire and action is to will. We know, feel, and act, and these are expressions of our intelligence, desire, and will. We have desires and we act on them in the light of what we know. The mind is designed to produce action based on knowledge in the satisfaction of desire. No doubt evolution produced this three-component structure as the best solution to survival requirements. The components must of course be coordinated, so they interact in various ways; but they are separate regions of what we indiscriminately call the mind. Also, they have many sub-components: many types of knowledge, from linguistic to ethical, physical to psychological; many types of desire, from sexual to food-directed, ethical to prudential; and many types of action, from mental to bodily, reflexive to considered, novel to routine. So there are modules within modules, faculties within faculties; in fact, the basic compartments are more like repositories of faculties and modules than faculties and modules. If we picture each compartment as a tree, each faculty within it is a branch of the tree–the sum total of trunk and branch (and leaves) being the tree. The many modules of mind can be viewed as clustering into three large groups, which I am calling intelligence, desire, and will. There is much heterogeneity within each group, as well as across groups, but we can still recognize the larger grouping—a fundamental similarity of mental faculties (compare the components of the respiratory and digestive systems of the body). If I were to draw a diagram, it would contain three large boxes with arrows connecting them and many dots within each box.
This picture is not like certain traditional pictures that seek to impose uniformity on the mind. The behaviorist views the mind as a single block of dispositions to behavior, triggered by external stimuli, as in the standard S-R model; if there is a black box mediating stimulus and response, it is a matter of conditioned connections. The empiricist picture views the mind as an array of sensations (ideas, impressions, sense-data) corresponding to perception and “inner sense”, with desires also giving rise to internal impressions. The cognitive scientist is apt to view the mind as a uniform set of computations or mental programs with no fundamental distinction drawn between the cognitive and the affective. But the tripartite picture insists that we are dealing with three very different sorts of mental reality—knowing, feeling, and doing. None of these is a special case of the other; each must be treated separately. Nor are we saying that the mind is an unruly collection of various elements with no overarching general categories, a mere set of family resemblances, an irreducible plurality. There is a strict and principled distinction between the three compartments, despite their obvious interactions. Knowledge is not emotion and emotion is not action. We really do contain three distinct types of mental entity; in the Table of Elements for the mind there are three columns. When people say things like, “In the beginning was the deed” they risk overlooking distinctions—as do rampant empiricists or gushing sentimentalists (in the philosophical sense). Knowledge and perception are not paradigms, but neither are desire and emotion or will and action. Nor is the mind a dualism of reason and emotion, or action and contemplation, or desire and reflective thought; it is a trinity of intelligence (knowledge), desire (emotion), and will (action). Any adequate psychology must begin from this recognition, as must any adequate philosophy of mind. That includes recognizing that will is not to be assimilated to desire: to desire or need something is not to will it or act so as to obtain it. The will is the servant of desire and need, but it is not a type of desire or need. The will must respect the promptings of intelligence as it goes about its practical business, since it must accept the reality of the objective world, whereas desire knows no such realism. Traditional thinkers were quite right to distinguish volition from appetite and ponder the freedom of the will (desire is not subject to free choice any more than knowledge is). Psychology thus consists of three parts: cognitive psychology, affective psychology, and volitive psychology (to revive an old-fashioned term). Where psychologists speak of the “motor system” and seek to elucidate its workings, we do better to recognize the whole volitional system of which mere bodily movement is a part—practical reasoning, decision-making, intention, and action. This is far from the behaviorist’s preferred ontology.
Are there any features common to the three psychological domains? Indeed there are: it is clear that a combinatorial logic applies to each of them, and that the conscious and the unconscious play their part in each. Language is obviously combinatorial, but so is thought, which means that knowledge is too. The rules of combination need not be the same, but each faculty consists of a finite set of primitive elements and a finite list of rules for conjoining them—whether perceptual primitives, or linguistic, or conceptual. Intelligence in general relies upon the creativity permitted by quasi-grammatical combination—the formation of complex entities from simpler ones according to rules. But this basic property applies also to desire and action: desires have logical and constituent structure, which enables them to proliferate indefinitely (the desires of man have no end); and so do actions because of means-end reasoning and action-plan embedding (consider building a house). Our possible actions are endless, though finitely based, just as our desires are unlimited despite our finiteness. Thus we might say that creativity is a general property of mind, applicable in all its operations. Psychology will seek to articulate the creativity in question, attempting to identify primitives and the rules that apply to them. Affective psychology is no exception: emotions too are complex inner occurrences with constituent structure (think of a feeling of wistful ennui on a fine summer’s day). Similarly, each compartment of the mind divides into a conscious part and an unconscious part—the part we see and the part that eludes us. There is conscious knowledge and conscious emotion and conscious willing—none of these faculties is wholly unconscious—but side by side with consciousness we have the unconscious processes that underlie consciousness. I won’t defend this position here but merely point out that the same basic division exists across the mind’s principal components. So we have two psychological universals despite the deep differences in the psychological realities to which they apply: the presence of combinatorial structure, and the division into conscious and unconscious. Perhaps too we can add the presence of a self that has these aspects: I think and I feel and I act. Of course, the question of the nature of the self is much debated, especially its psychological robustness, but it seems true to say that the mind contains some sort of capacity to think I-thoughts with respect to each compartment that composes it. Not that this in any way compromises the heterogeneity of the components, any more than the previous two points do, but it does indicate a principle of integration or coordination that we should acknowledge. I am a knower, a feeler, and an actor—I subsume these three categories without being one rather than another. The I is not exclusively one of them but the totality of them (so it is not, for instance, the agent of Reason alone). This allows us to speak of unification with respect to the aspects of mind. Thus generative capacity, a conscious/unconscious divide, and selfhood all work to confer an overarching unity on the mind conceived as a collection of separate sui generis systems. The trinity is not absolute, nor unbridgeable; there are common features (the body is not dissimilar). If we think of the mind as made up of distinct buildings, the buildings are unique to themselves, but bricks and mortar are used to construct each of them. The process of evolution has employed generative mechanisms in the design of each of the mind’s compartments, as well as a conscious/unconscious division of labor and an overarching agency we call the self, while ensuring that the architecture varies from one compartment to another—rather as a church is one thing, a home another, and a prison a third. Function and form vary from one compartment to another, though some common principles are applicable universally.
The fundamental problem in designing an organism is that an organism exists in a real and possibly threatening world in which it must act to preserve itself. The way to solve this problem is to install a faculty for being informed about the world, a set of motivating inner states that reflect the organism’s needs, and a capacity to act effectively in the world. Thus it is that organisms come to possess intelligence, desire, and will—the basic prerequisites for survival. The large-scale composition of the mind results from the existential predicament of an evolved organism. The study of mind should reflect this threefold structure. 
 Recent philosophy of action has tended to downplay the distinctness of desire and will, as in belief-desire psychology, but really we need to make a firm distinction between desire and decision. The concept of intention is not the concept of a certain type of desire, as it might be the strongest desire of the agent at the time in question. The faculty of will is not to be assimilated to mere desire: it involves a distinctive type of reasoning and must respect the facts, as they are known to the agent. Intention is no more desire (or emotion) than thought is perception.
 I have said little here about the general nature of the three sorts of capacity I have identified, presuming some prior understanding, but if I were to sum up what distinguishes the capacities I would say this: knowledge is a truth-oriented state, desire is a well-being oriented state, and will is a survival-oriented state. Knowledge seeks to get the world right (to fit it), desire reflects the inner needs of the organism (mental and physical), and will strives to make reality serve the organism’s urge to live. These are different jobs and the capacities involved operate accordingly. For example, one can choose to act but not to know (or believe), and one can desire the impossible but not intend the impossible. Knowledge, desire, and intention have different “logics”.