Capabilities: An Ontology

The above characterizations suggest the following hallmarks of capabilities, namely that:

We believe that an accurate ontological characterization of capabilities should reflect these hallmarks. In what follows, we will propose such a characterization, taking inspiration from the inclusive philosophical characterization of capabilities in terms of what is good for a bearer or its community [2], but adding precision, and pointing to applications which reveal the need to broaden the account beyond the focus of what is good for the bearer.

Terms in BFO and in BFO-conformant ontologies represent classes of instances that share important features. The highest division in BFO's class taxonomy is that between occurrent and continuant. Occurrents are either (i) extended in time in such a way as to have temporal parts (phases, stages, ...) which are extended over time; these are either processes or the temporal regions in which processes occur, or (ii) they are the boundaries, for example beginnings and endings, of such processes or of the associated temporal intervals, or (iii) they are spatiotemporal regions linking temporal regions to space on the continuant side of BFO.

Continuants, on the other hand, (i) lack temporal parts, (ii) endure self-identically through time, and (iii) are typically able to change their qualities and to gain and lose parts in the course of their existence. Continuants and occurents are tied together by the fact that the former participate in processes as when your mother participates in an instance of jaywalking. The continuant class has three subclasses, as illustrated in Figure 1. First, an independent continuant is a continuant that does not depend on anything for its existence [25].⁵ A baseball is an independent continuant. The mass and shape of the baseball are specifically dependent continuants. Each instance of the latter depends for its existence on some specific instance of the former.

Independent continuant has two BFO sub-classes, namely material entity and immaterial entity, which consist, respectively, of entities having and entities lacking matter as parts.⁶ Subclasses of material entity include objects, such as Mick Jagger, and object aggregates, such as the Rolling Stones.⁷ Subclasses of immaterial entity include spatial regions and sites (for example: the Rafah Crossing, the Mariana Trench), as well as various continuant boundary entities (for example, the Equator).

Certain instances of specifically dependent continuant are fully manifested whenever they manifest at all, such as color, shape, or mass; these are instances of the class quality. Realizable entities, in contrast are those specifically dependent continuants which are marked by the fact that they need not manifest when they exist. If an apple can float in water, it possesses this ability even when it is not in water. Realizable entities, in sum, must be realizable, but they are not in every case realized. Two major subclasses of realizable entity recognized by BFO are dispositions and roles. Dispositions are realizable entities that are internally grounded. This means that, for a disposition to begin or cease to exist, its bearer must undergo a physical change.⁸ For example, a portion of salt may lose its

solubility, but only if it undergoes some physical change to its lattice structure [29]. Roles, in contrast, must be externally grounded. This means that the gain or loss of a role – for example your promotion to a new rank – does not imply change in your physical makeup.

The class disposition has a single subclass recognized in BFO, namely function, which is (roughly) a disposition that reflects the reason for the existence of its bearer.⁹ Functions fall into two main types. On the one hand are functions of artifacts, which are entities designed and intentionally created to realize some function. On the other hand are functions of biological entities. A human heart bears a function to pump blood. The heart evolved in virtue of the fact that an organ fulfilling such a purpose was instrumental in keeping our ancestors alive.

A generically dependent continuant is (roughly) a copyable pattern. A pattern of this sort exists only if it is concretized in some continuant bearer; but it is not dependent on any specific bearer, because it may be copied (for example through being transmitted) from one bearer to another. Here, again, there are two major subclasses. On the one hand are information artifacts, such as digital blueprints or embroidery patterns. On the other hand are biological examples, such as nucleotide sequences. Table 1 provides the definitions or (in the case of primitives) elucidations of terms in the BFO hierarchy.¹⁰

Capabilities are in every case dispositions whose realizations are associated with some goal or, more generally with some interest, which an organism or group of organisms has. If you have an interest in a thing in the sense at issue here, this implies that whatever affects the thing directly can have a direct or indirect effect on you. To have an interest in something is to not be a disinterested party. You have an interest in keeping your neighborhood clean. You do not have an interest in keeping clean the surfaces of passing asteroids. In the relevant sense here, therefore, the meaning of 'interest in' is skew to what we might call the curiosity sense of 'interest' (with negative form uninterested in) that is manifested, for example, in scientific research.

Having an interest in the realization of a capability is a relation which holds between organisms or groups of organisms and processes that are realizations of dispositions in some material entity. The reference to groups turns on the essentially collective nature of many capabilities. One person alone does not have the capability to dance the foxtrot, for example. It has been argued that language, too, is an essentially collective capability [34].

There is an important special class of interests which arise through the presence of goals. Goals are phenomena of a type characteristic of human organisms in that they go beyond mere survival and reproduction. When someone has a goal, then they have at least a minimal plan to achieve that goal, and at least some disposition, however weak or incipient, to realize the plan. If, for example, your goal is to own a Ferrari, then you must have at least a minimal plan to raise the needed funds, and you will then, given your goal,

have an interest in processes of the type prescribed by that plan. In many such cases, realizing the plan will involve the creation of new capabilities. Complex plans, such as launching a space station into orbit, will involve the specification of huge numbers of processes chained together at many levels. Many of these processes will require the creation of specific capabilities on the side of both humans and machines. Many of the latter will be functions of the relevant artifacts, namely in those cases where artifacts are brought into being because of a plan to create an entity that can realize processes of a certain sort.

Plans and goals aside, there are endlessly many cases where non-human organisms have an interest, though we cannot properly speak of their 'having goals'. There is some residual sense in talking of survival and reproduction as goals of, for example, a nematode worm. But then the features that we associate with having goals on the part of humans¹² are absent. Our proposal thus covers cases where interest is and is not related to goals.

We take 'has an interest in' as a primitive relational expression, which means that we cannot provide a non-circular definition [35]. We can however assert necessary conditions for the relation to obtain:

o has an interest in p only if

These conditions allow that one need not be aware that one has interest in realizations of some process in order to have a corresponding interest, as is the case when a nematode has an interest in survival, or your grandfather has an interest acetylcholine uptake in his synapses.¹³

There are similarities between capabilities and functions. First, any instance of function exists in virtue of its bearer's physical makeup, which is a feature shared with capabilities. Each instance of function is further such that its realizations can be evaluated according to some standard [31]. The realizations of capabilities, too, can be evaluated in this way. Your car's capability to transmit in stereo may be realized with a signal of greater or lesser clarity.

But there are also differences. Human beings (in our view) do not have functions, but they do have capabilities, because they have parts with functions whose realization contributes to their survival. My digestive system, for instance has the function to digest food, and therefore I have the capability to digest food. Similarly, our flathead screwdriver bears a function to drive screws using torque, but it may also, as we saw, bear the disposition to open paint cans. And if people have an interest in using a screwdriver in this way, then its disposition to open paint cans acquires the status of a capability.

Additionally, each instance of function is such that we can advert to this function in explaining how its bearer came into existence. The presence of a capability, in contrast, need have no etiological consequences of this sort.

We can now offer the following definition of capability:

$x$ is a capability just in case $x$ is a disposition in whose realization some organism or group of organisms has or had¹⁴ an interest.

The above observations motivate our conclusion that not all capabilities are functions. Nevertheless, all functions are capabilities. A function in BFO is borne either:

In either case there is some organism or group of organisms which has an interest in the realization of a function, and since the function is a disposition, they have an interest also in the realization of a disposition. If $x$ is a disposition in whose realizations an organism has an interest, then $x$ is a capability. It follows that all functions are capabilities.

Our account helps to disambiguate certain natural language uses of ‘function’ and ‘role’. The term ‘functional role’, for example, is often used to describe some key individual within an organization who must perform certain activities to ensure that the organization operates properly. In BFO, such activities would involve individuals bearing roles of the mentioned sort. But the bearer of such a role, for example the mayor of a city, must in addition have the capabilities needed to perform the required operations, such as speaking the relevant language. In short, the mayor’s ‘functional role’ is indeed simply a role, but one whose realization depends on various capabilities, whether pre-existing or acquired on the job.

Consider, similarly, that part of the literature on functions which distinguishes between ‘primary’ and ‘secondary’ functions [37]. The primary function of a car engine is to enable motion of the car. This it achieves through the realization of secondary functions borne, for example, by piston parts, functions which they realize by combusting gasoline. Here both primary and secondary functions satisfy our definition of function simpliciter. A secondary function is a function whose realization enables an object to perform its primary function. The significance of this idea turns on the fact that one might design engines that accomplish the same primary function by realizing different secondary functions, for example by means of an engine whose parts are designed to combust diesel fuel or methane.

In this way, distinguishing between primary and secondary functions can become part of a strategy to achieve cost-effective artifact design. For example, a car with an internal combustion engine emits considerable heat following combustion. The internal combustion

engine bears neither a primary nor a secondary function to produce excess heat. However, because the heat produced is sufficient to warm a car cabin at no additional energy cost, the combustion engine bears a capability to produce excess heat. It is recognition of such a capability during design of a car heating system that is leveraged to reduce costs by having excess heat diverted into the car cabin. In other words, the primary function of a car heating system is partially enabled by the capability of the engine to produce excess heat.

When does a capability cease to exist? Here we defend an account that is modelled on the account we provide of the end-of-life for functions. According to BFO, a function exists if and to the extent that there is a real possibility for it to be realized [30]. Whether the relevant possibility exists turns on the intrinsic physical structure of the bearer of the function. If the old heater in my attic is undamaged then it continues to have the function of a heater, and this would be so, providing its mechanism survives intact, even if the heater were to be encased in concrete. If, on the other hand, the heater is broken beyond repair, then it thereby loses its function. Functions may on this view become obsolete, but they still survive as functions providing that the bearer has suffered no physical changes of a sort that would preclude realization.

A similar argument, now, can be applied to capabilities, resulting in the following constraint:

If $x$ has an interest in the realization of disposition $y$ at time $t$, then $y$ is a capability at $t$ and at all subsequent times during which $y$ exists.

A Betamax player, still today, bears a function to play Betamax tapes, and this is so even if no one is left who has an interest in realizing this function. Since every function is a capability, it follows trivially that the Betamax player bears a capability to play Betamax tapes independently of any surviving interest. As a perhaps more extreme example, consider the discovery of an ancient artifact – a stick, of a type used in certain now forgotten rituals of human sacrifice. No one today has an interest in realizations of the specific dispositions borne by this specific stick. But the sacrificial high priest had such an interest. Since, in the intervening centuries, the stick is (by assumption) not physically changed, it follows that it still has the corresponding capabilities. This is a desirable consequence: among the reasons archeologists have sought intact exemplars of a stick of this type was precisely because of the desire to test their conjectures concerning their capabilities.

Capabilities begin to exist either when a disposition begins to exist in response to the interests of some organism, or when an already existing disposition becomes a capability because an organism acquires an interest in its realization. That many capabilities are being created ab ovo is revealed by annual patent statistics. Pre-existing capabilities may be discovered independently, for example by different groups of researchers. Much as the physical basis of a disposition underwrites its existence independent of any awareness, so interest in the realizations of a disposition underwrites its existence as a capability independent of any awareness of this interest. There are many dispositions, for example dispositions of many of the cells in our bodies, of which we are not aware. And thus, given that we have an interest in the functioning of these cells, there are many capabilities of which we are not aware. Sam's pancreas bears a function to produce insulin. Sam has an interest in this function being realized. But Sam need not have any accompanying knowledge associated with producing insulin.

That dispositions are capabilities may be discovered. In 1971 an organization called 'Federal Express' was created, with the function to deliver parcels. In the year 2000 there was founded a new organization in the Fedex family, organization that has since 2009 been titled 'Fedex Logistics'. FedEx, it transpired, had been providing logistics services for many years, but did not at first realize that it was in possession of a separable logistics capability from the exercise of which it could make money [38].

One criticism of our proposal is that it would seem to depart from the scientific orientation of BFO because it is not morally neutral. It seems, in some way, to make 'being a capability' rest on a distinction among dispositions between the good and the bad. To see that this is not so, consider the case of a human being who is a functional sociopath. He lacks a conscience and is willing and able to kill with impunity. This lack of a conscience is not, from your and our perspective, a capability. But from the perspective of a drug cartel mercenary army the underlying dispositions are most surely capabilities. Whether a disposition is or is not a capability may in this way depend on the interests of the parties involved.

We note that a parallel concern arises also in the case of roles. Many roles are by their nature social constructions; they depend on institutions and groups, and new roles – the role of picciotti d'onore of the 'Ndrangheta, for example – may be created and assigned in morally neutral or morally loaded ways.¹⁵ Both role and capability capture complex phenomena limited only by the creativity of human beings. These facts are not in conflict with the scientific basis of BFO. Even so, one may still object that, according to our proposal, capabilities may be created too easily, almost effortlessly, simply by someone's having an interest in realizations of a certain type. In response, note that there are, importantly, constraints on the sorts of dispositions in which we can have an interest. First, having an interest implies something like having a stake in some object's future destiny – your daughter, for example, but not the twin Earth counterpart of your daughter. Second, interest in is always de re, and not merely de dicto. If I have an interest in eliminating a squeak in a door hinge and some substance exists in the world with lubricating dispositions, it does not follow that those dispositions are now capabilities. My interest is in processes realizing the elimination of the squeak in this door hinge that are within the realm of what I can bring about causally. Thus, while interest in is the ultimate arbiter of whether a disposition is a capability, the specificity of interest is a delimiting factor.

One may object that it is unreasonable to accept that any disposition, without undergoing any change, can suddenly transform into a capability. A change does occur,

however; for as a result of this transformation the disposition gains a relation to the salient organism or group of organisms that it did not have before. It should, moreover, be no surprise that the class of capabilities represents an easily expandable terrain. Our interests are vast and varied. If my enemies have an interest in my death and I have a cancerous tumor in my brain, then the tumor bears dispositions that my enemies have an interest in seeing realized. Under these circumstances my tumor bears capabilities. This is as it should be. On the other hand, I have numerous dispositions in whose realization no one has an interest, my enemies included, and so these are not capabilities. This, too, is as it should be.