# An ontological analysis of risk in Basic Formal Ontology

Adrien Barton, Federico Donato

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Adrien Barton, Federico Donato. An ontological analysis of risk in Basic Formal Ontology. Semantic Technology for Intelligence, Defense, and Security (STIDS 2024), Oct 2024, Woodbridge, United States. hal-05528820

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# An ontological analysis of risk in Basic Formal Ontology

Federico Donato

Department of Philosophy SUNY at Buffalo
NCOR

Buffalo, USA

fdonato@buffalo.edu

Adrien Barton

IRIT, CNRS

Université de Toulouse
Toulouse, France

adrien.barton@irit.fr

***Abstract***—The paper explores the nature of risk, providing a characterization using the categories of the Basic Formal Ontology (BFO). It argues that the category Risk is a subclass of BFO:Role, contrasting it with a similar view classifying Risk as a subclass of BFO:Disposition. This modeling choice is applied on one example of risk, which represents objects, processes (both physical and mental) and their interrelations, then generalizing from the instances in the example to obtain an overall analysis of risk, making explicit what are the sufficient conditions for being a risk. Plausible necessary conditions are also mentioned for future work.

***Index Terms***—ontology, risk, BFO, role, disposition

## I. RISK DATABASES AND ONTOLOGIES

### A. *The need for a risk ontology*

Risks are ubiquitous. Your likelihood of receiving a loan and the interest rates associated with the loan are directly correlated to the risk the bank sees in losing its money if you fail to repay it. Companies in the stock market are evaluated by brokers and investors based on their risk profile. Policymakers ponder whether a hydrogeological plant will put the environment at risk and how this will negatively affect their net political campaign. Physicians recommend cost-benefit analyses to their patients for surgical operations that could potentially extend their lives, but also pose risks. Risks can be severe or minor and present in the population according to various statistical distributions. Risky situations, such as in a terrorist emergency, can arguably exist even if the terrorist attack is just suspected but never occurs.

These plausible natural language descriptions of events related to risk can be found in terminologies, contracts, and many other documents. Moreover, in today's information-driven society, risks are stored and analyzed using databases and risk analysis equations. The databases focusing on this specific domain are called risk registers, and they can track all kinds of risks, connecting them to people, processes, economical assets, medical status, locations and times [1]. However, the conceptual foundations of risk lack clarity and there are ongoing discussions in both the natural language and database communities regarding risk [2]. Despite the prevalence of risk discussions, there is no universally accepted definition among all scholars or institutions, which hinders effective action to prevent or mitigate risk. The confusion is

exacerbated by the numerous complex vocabulary terms and database fields that seem to be linked to or depend on risk, such as “risk propagation”, “risk prevention”, “risk aggregation”, “vulnerability” and “cybersecurity”, among many others [3] [4]. In fact, precise knowledge of what is at risk, what causes risk, and how many risks there are is essential for an intervention that is timely and proportional to the prospected damage.

Questions that still pertain to the contemporary theory of risk include: What is the nature of risks (material entities, beliefs, special kinds of probabilities)? Is the risk of losing the reputation of my company identical to the opportunity of a rival company to gain reputation? Does a risk that never realizes actually exist? Is risk objective or subjective, absolute or relative? As a preliminary to address these questions, we will propose an explicit and logically-based definition or risk based on top-level ontology categories.

## II. DEFINITIONS OF RISK AND THEIR ELEMENTS

Ontologies are information artifacts that specify meanings of terms and capture our knowledge of the world, categorize the relevant entities of a domain in hierarchies, leverage logical deduction, and enable interoperability between diverse databases [5]. We align our framework with the Basic Formal Ontology [6], a widely used top-level ontology that provides common ground for building domain ontologies and establishing a common semantics across diverse databases [7]. To our knowledge, only two other risk ontologies have been aligned with top-level ones, indicating that the research field is still relatively underdeveloped [8] [9]. This paper will argue step by step for the following sufficient condition on being a risk:

*If:* (i) *r* is a role &

(ii) *r* is externally grounded in an aversion that an agent or group of agents have towards the possible realizations of the role,

then *r* is a risk.

In order to understand risk, we need to define the terms that are involved in the condition, namely something that is risky or the source of risk, something that is put at stake
or at risk, something that is valuable or desirable, and some
process that might involve uncertainty, as risk is commonly
understood [10]. The implication of values, interests or desires
in the definition of risk might raise questions on the subjective
or objective nature of risks [11] [12]. We will consider the
interplay between subjectivity and objectivity, especially with
the relation of external grounding.

To develop a comprehensive understanding of risk, we aim
to create an Aristotelian definition, that categorizes the entity
within a genus, namely a superclass, and using a differentia,
which explains how it differs from other entities within the
same genus, and clarifies its ontological relations with other
entities [13]. Structuring a definition in an Aristotelian way
helps translating it in a logical form, enabling automatic
reasoning.

This short paper proposes an exploration in a new direction
that the ontology literature has not considered so far. The
paper is structured as follows: the third section contrasts two
conceptions of risks as BFO:Disposition and BFO:Role; the
fourth section considers the subjective side of risk, involving
a mental attitude of an agent and the target of this mental
attitude; the conclusion provides a way of categorizing risk
with sufficient conditions, also listing further works to expand
the ontology and limitations of the present ontological model.

### III. RISKS AS REALIZABLE ENTITIES

Having introduced a general picture of what risk plausibly
is and some open questions about it, we now turn to a
unified definition of risk. In this section, we propose a view
of risk as a realizable and externally grounded property. In
this formulation, externality is understood as involving two
or more mereologically distinct entities [14], while grounding
is a relation between entities in which one exists because of
the other [6, p. 100] [15]. We will examine two views that
meet those requirements: risk as a disposition and risk as a
role, ultimately favoring the latter. Both views on risk are
developed in the BFO framework, which is briefly explained
in the following.

BFO is a top-level ontology [6] that identifies two
very general classes of entities, continuants and occurrents.
Continuants can endure in time, existing at different times and
changing through them, whereas occurrents are temporally
extended and have temporal parts, but cannot change in time.
Examples of continuants include an orange and its mass
of 200g, both of which exist for a certain period of time.
In contrast, occurrents include the ripening process of the
orange and the time span during which it occurs. Continuants
encompass various entities, including material entities and
properties, named "specifically dependent continuants" (SDC)
in BFO. SDCs include qualities, such as the orange's mass,
as well as latent properties that can be realized in a process.
Those latent properties, called "realizable entities", include
dispositions, that depend solely on the physical make-up
of the entity. For instance, an orange has the disposition to
dry out under the hot sun, even when it is fully hydrated
and no drying process is occurring. This disposition exists

independently of the orange's current state. They also include
properties that do not depend only on the physical make-up
of the entity, like the role of this orange of being the winner
in a fruit competition, after being chosen by a jury. More
specifically, BFO defines dispositions and roles as follows
[15]:

d is a disposition $=def$ (i) d is a realizable entity & (ii)
d's bearer is some material entity & (iii) d is such that, if it
ceases to exist, then its bearer is physically changed & (iv)
d's realization occurs because this bearer is in some special
physical circumstances & (v) this realization occurs in virtue
of the bearer's physical make-up.

r is a role $=def$ (i) r is a realizable entity & (ii) r exists
because there is some single bearer that is in some special
physical, social, or institutional set of circumstances in which
this bearer does not have to be & (iii) r is not such that, if
it ceases to exist, then the physical make-up of the bearer is
thereby changed.

To illustrate the analysis of risks within the BFO framework,
consider the following scenario: Paul is walking under a
ceiling (named ceiling₀) that is unstable and might fall over
him. Paul is a BFO:Object and ceiling₀ a BFO:Material entity,
which bears a disposition instability₀ that might be realized
in a process of collapsing (in which case it will be called
collapsing₀), which has as participant ceiling₀. If it is unde-
sirable for Paul that ceiling₀ would collapse on him, then a
corresponding risk arises when he is in the room. This scenario
raises a fundamental question: to which ontological category
do individual risks belong? We will examine two competing
views: the first [17] posits that risks are dispositions, while this
paper will propose an alternative view according to which they
are roles. We will present both views in order to compare their
strengths and weaknesses.

#### A. First Alternative: Risks as Dispositions

Grenier and Barton [17] argue that risks are dispositions
whose realizations are undesirable for certain agents. For
every agent $x_i$, they introduce the class of dispositions whose
possible realizations are undesirable for $x_i$, named here Risk<sup>d</sup>-
*for-x<sub>i</sub>*. Then, they introduce a class (written here Risk<sup>d</sup>) which
is the union class of the classes Risk<sup>d</sup>-*for-x<sub>i</sub>* for all i (thus,
Risk<sup>d</sup>-*for-x<sub>i</sub>* is a subclass of Risk<sup>d</sup> which is a subclass of
BFO:Disposition; note that since Risk<sup>d</sup>-*for-x<sub>i</sub>* explicitly men-
tions an individual $x_i$, it is arguably not a bona fide universal
but a defined class or collection of particulars, as introduced
by Smith and Ceusters [18]).

According to this view, a disposition $d_0$ can be an instance
of Risk<sup>d</sup>-*for-x<sub>i</sub>* at one time but not at another, depending on
the agent $x_i$'s attitude towards the possible realizations of
$d_0$ at those times: more precisely, depending on whether $x_i$
finds $d_0$'s possible realization undesirable or not. In the above
mentioned example, when Paul leaves the room and becomes
indifferent to the possible collapse of ceiling₀, instability₀ is
no longer an instance of Risk<sup>d</sup>-for-Paul, although it continues
to exist and is still a disposition. This conception attempts to
capture the dual nature of risk: the dispositional nature of an
instance of Risk<sup>d</sup> captures the objective side of risk, whereas
the fact that this disposition instantiates Risk<sup>d</sup>-for-Paul is based
on Paul's desires and reflects the subjective nature of risk, thus
resolving one of the questions we posed in the introduction.

Let's revisit two features of risks that must be taken into
account: realizability and external grounding. In this view, risk
is a disposition, and thus a realizable entity. A disposition is
a risk (or not) based on external entities, namely the desires
of some agent; thus, although its existence does not depend
on such external entities (instability₀ exists independently of
the mental attitudes of Paul), its risk status (the fact that
it instantiates Risk<sup>d</sup>) does. To summarize, in this view, a
disposition that is a risk is internally grounded in the sense
that it exists independently of the external world (see [19] for
more considerations on grounding); but its risk status (that
is, the fact that it instantiates the class Risk<sup>d</sup>) is externally
grounded, as it is contingent upon external factors. To illustrate
this distinction, consider a similar example. The rectangular
shape of this table (a quality) is not externally grounded, but it
could instantiate the class *Shape-seen-by-Paul* (which is, again,
a defined class and not a *bona fide* universal) based on external
features (namely Paul seeing this shape). Therefore, in this
view, a disposition is not a risk essentially but accidentally: a
disposition can become a risk, and a risk can lose its risk status
and become a mere disposition, based on the desires of agents.
Note also that in the dispositional approach, collapsing₀ is
an instance of a more specific subclass than BFO:Process, in
this case an instance of the defined class *Process-undesirable-
for-Paul*. This instantiation is accidental, similarly to the
accidental character of the instantiation of Risk<sup>d</sup>-for-Paul by
instability₀. Fig. 1 summarizes this approach:

<figure><img src="image_2.png" /><figcaption>Fig. 1. *Risk<sup>d</sup> as a BFO:Disposition*</figcaption></figure>

B. *Second Alternative: Risks as roles*

Let us now contrast this dispositional approach with a
new approach according to which risks are another kind of
realizable entity, namely roles. To contrast the two views, a
risk according to the dispositional approach will be called a
“dispositional risk”, and a risk according to the role approach
will be called a “risk role”.

To put it informally, roles are SDCs that existentially depend
on the context in which they are present. Instead of having a
disposition that starts and stops instantiating Risk<sup>d</sup>-for-Paul at
different times, we can think of an instance of a class named
Risk<sup>r</sup>, itself a subclass of BFO:Role, which remains a risk
throughout its existence. As in the dispositional approach, the
role approach considers a risk as a BFO:Realizable Entity,
since it can be activated and realized. It also agrees with the
dispositional approach in considering the source of risk as
ceiling<sub>0</sub>, a material entity bearing properties relevant for the
risky situation. In the ceiling example, we will say that ceiling<sub>0</sub>
bears a risk role hazard<sub>0</sub> when Paul is located under it and
wants to preserve his health.

As in the first alternative, what makes ceiling₀ risky for Paul is external to ceiling₀. Additionally, ceiling₀ does not bear the risk role hazard₀ by necessity: it does so because of the context, which consists of Paul being in the vicinity of the ceiling, desiring not to be hurt, and of ceiling₀ being unstable. Expanding the scenario, if Vladimir, an enemy of Paul, wanted him crushed, then the instability of ceiling₀ would not be a risk for Vladimir, but an opportunity for him. So, ceiling₀ does not bear a risk on its own, independently of the rest of the world, but due to the mental attitudes of some agents. Similarly, in the dispositional approach, instability₀ is an instance of Risk<sup>d</sup> based on external features, namely in virtue of the desires of Paul.

The dispositional approach and the role approach have sim-
ilarities and differences in how they deal with this externally-
grounded character of risk. In both approaches, as we saw,
a material entity bears a dispositional risk or a risk role on
the basis of external features. According to the dispositional
approach, as explained earlier, a disposition can become or
stop being a risk - similarly to a human who can continue to
exist as he grows up even if he is not a child anymore. For
example, instability₀ continues to exist even if it is not a risk
anymore for anyone. According to the role approach, on the
other hand, the risk cannot stop being a risk: if a situation is
not risky anymore, the corresponding risk role disappears<fnref n="1" />. For
example, if Paul's desires change and he doesn't care anymore
about being hurt, then the role hazard₀ disappears: it cannot
exist without being a risk.

C. *The realizations of the risk-related realizable entities*

Note that the role approach does not deny the existence
of dispositions such as instability₀: it just denies that this
disposition is a risk and construes instead the risk as a role.
Thus, the debate between both approaches can be seen as a
question whether to map the natural language term “risk” with
Risk<sup>d</sup> or Risk<sup>r</sup>.

In this approach, the material object ceiling₀ bears two
different realizable entities, the disposition instability₀ and
the role hazard₀. Their realizations are related but different.
If realized, instability₀ would bring about a BFO:Process

<footnote n="1">¹Thus, one might say that an instance of Risk<sup>r</sup> is necessarily so, whereas an instance of Risk<sup>d</sup> is accidentally so.</footnote>
of collapse in which the materials composing ceiling₀ loose
cohesion and fall down under the action of gravity. In our
scenario, this physical process is collapsing₀, which would
happen independently of whether Paul is at risk or not. On
the other hand, considering that the integrity of Paul, a normal
human being, can be negatively impacted by the falling debris,
and that he does not want such an outcome to happen, we
identify the realization of hazard₀ (the risk) as a process of
causing damage to Paul. This is a BFO:Process named here
damaging₀ in which Paul's health is negatively affected. Note
that collapsing₀ and damaging₀ happen approximately at the
same time. If we just focus, to make things simple, on the
c ceiling debris that hit Paul and not those ten meters from him,
the falling, physical impact, and biological damage all happen
in the same approximate place and time, and with overlapping
participants. This does not imply that those processes are
identical though.

Fundamentally, collapsing₀ and damaging₀ can be analyzed
as sums of spatial changes (change in spatial position of a
material entity) and SDC changes respectively, where a SDC
change is a BFO:Process that consist in a change of one
or several SDCs (following Guarino, Baratella and Guizzardi
[20], adapted to BFO by Toyoshima and Barton [21]). One can
define collapsing₀ as the sum of processes of SDC changes
(e.g. the structural cohesion of the ceiling that decreases) and
processes of spatial changes (the spatial location of the ceiling
debris which move down). damaging₀, on the other hand,
might be defined as a change of SDCs characterizing Paul's
health (without taking any specific position on the ontology
of health here), which declines while he is hit by those bricks
falling down<fnref n="2" />. So, those two groups of quality changes co-
occur in spatio-temporal regions that are close from each other
but different. Therefore, the role approach admits an addi-
tional realizable entity compared to the dispositional approach,
namely hazard₀; and hazard₀ and instability₀ are realized in
different processes. This is another point of difference with
the dispositional approach, which involved only one process,
closing, and its classification in a specific subclass.

D. *Merely possible processes*

A central tenet of all discourses about risk is possibility.
We have identified three processes so far: Paul actively enter-
taining a desiring process of not being hurt, collapsing, and
damaging. However, even if none of these three processes
would happen - in particular, if instability and hazard would
have no realization, the whole situation is a risky one. How can
we then express this unrealized possibility in the ontology?

A first solution, following [22] would be to state that, if
realized, instability is realized in an instance of the class
ceiling_closing (which is, here too, a defined class and
not a universal). This can be formalized with the axiom (O1):

(O1) instability₀ realized_in only ceiling₀_closing

However, a challenge with (O1) is that according to BFO,
only classes that have an instance existing in our world (be it
in the past, present, and/or future) can be introduced.

This means that the class *ceiling₀_closing* might not
exist, as there might be no collapse of ceiling₀ in the history
of our world, and thus should not be introduced.

A possible way to deal with this problem is to formalize
an axiom (O2) slightly differently by introducing instead the
universal *Collapsing*<fnref n="3" />.

(O2) instability₀ realized_in only (*Collapsing* and
*has_participant* value ceiling₀)

For sure, some material entities have collapsed in the history
of our world; therefore, the universal *Collapsing* exists accord-
ing to BFO. Thus, the axiom O2 and the entities mentioned
there can fit into BFO’s metaphysical framework. This strategy
can be straightforwardly adapted to the processes of Paul being
damaged or Paul actively desiring not to be hurt.

IV. CONATIVE THEORIES OR RISK

A. *A knowledge agnostic approach*

According to both the dispositional and the role approach,
risks come into existence because some unwanted outcomes
that would negatively impact an agent might occur. So far,
we have modeled this condition with a process of desiring
entertained by an agent, in our case Paul, or some other
conative mental state. Paul might walk under the ceiling with
or without knowledge of its instability, holding a desire of
self-preservation in both cases. Many publications on risk
analysis focus on what an agent knows or forecasts about
possible situations and which actions he takes or avoids given
their beliefs [23]. Some other studies consider whether some
of these actions are rational or ethical [24]. Here, we only
focus on the metaphysics of risk, and we argue that the
knowledge of Paul is not relevant for determining what is
a risk for him: when ceiling₀ is unstable and Paul stands
below, the risk is there, independently of his knowledge of
the situation. Similarly, the appropriate ethical response to a
risk has no bearing on the metaphysics of risk. Therefore,
epistemological or ethical features are largely irrelevant to
our current investigation. Invoking desires allows us to have a
belief-agnostic approach in modeling risk, which means in our
scenario that the beliefs and knowledge of Paul are irrelevant
to determine what is risky. Paul’s beliefs and course of actions
could determine whether he is a good risk assessor and his
degree of risk aversion, but this is a matter for decision theory
or psychology of decision making. Additionally, as already
hinted in the section on merely possible processes, Paul could
be ignorant about his own desires, by having a dispositional
desire that remains unrealized in explicit mental processes.
In this we follow a tradition analyzing many mental entities

<footnote n="2">²Thus, collapsing₀ and damaging₀ could be related to process profiles,
which formed a subclass of BFO:Process until BFO2.0.</footnote>

<footnote n="3">³The authors thank Barry Smith for suggesting this idea in a private discussion. Note that ‘has_participant value ceiling₀’ refers, in OWL Manchester syntax, to the class of entities that have as participant ceiling₀</footnote>
as dispositions, including beliefs, desires, and intentions [25]. The desire disposition can remain latent for some time and can be realized in mental desiring processes, typically conscious, but that might be unconscious [26]. If Paul is sleeping or comatose under ceiling₀, there is still a risk that it would collapse on him, even without a conscious process of desiring safety, and independently of his (dispositional) beliefs.

## B. Desires and aversions

We consider here desires as mental dispositions directed towards some objects. Moreover, given that risks concern scenarios in which some damage or problem might occur, it seems the desires relevant for risk scenarios are connected to something that might not happen. What seems easy from a linguistic point of view is more difficult from an ontological point of view. It is classically problematic for ontology to deal with negation or inexistence [27].

First of all, it is relevant to distinguish between desiring not-x and not desiring x. The first case concerns an active process of the mind wishing that a certain state of affairs would not obtain. In the second case, a mental process is lacking: even stones can be said to not desire something, whereas they certainly cannot desire not-x.

When risk roles are realized in processes, those processes are contrary to an agent's desires. But realist ontologies do not accept things such as negative processes or negative objects - or more generally negative entities (see also [28] and [29]). The negation is rather embedded in a peculiar mental entity opposite to desiring. As in the mental realm love is the opposite of hate and hope is the opposite of despair, we can consider the mental attitude of aversion, which is the opposite of desiring, and might satisfy statements such as: "if an agent desires x, then he does not avert x". Similarly to desires, aversions are dispositions that can be realized in mental processes - in this case, processes of averting. This therefore dispenses us from introducing problematic entities as negations in our model, and only connects existing entities together. To be more precise, mental attitudes like aversions and desires are connected to what they represent by what is usually called a relation of "intentionality" or "aboutness" [30], which we will call here "is_directed_towards".

## C. Intentionality towards Risk Realizations

Having tackled the negativity of certain mental conative entities like aversion doesn't settle the issue of which real-world entity does Paul avert - that is, towards which entity is the mental attitude of aversion directed. Entities that Paul might avert include ceiling₀, its disposition instability₀, the process collapsing₀ or the process damaging₀. What Paul fundamentally averts is to be bodily hurt, so he would avert the process damaging₀, which would realize the risk hazard₀. However, his mental attitude of aversion would exist even if hazard₀ was not realized in the process damaging₀. Exploiting a similar solution to (O2) that we have seen with merely possible processes, we can say that aversion₀ can only have an intentionality relation with something that is a

damaging process, if any, and that this process has Paul as its passive participant, since he would take the damage<fnref n="4" />. In OWL:

(O3) aversion₀ is_directed_towards only (Damaging and has_participant value Paul)

In this way, the sentence (O3) can be added in an ontology and be true even if there were no specific instances of *Damaging* involving Paul at the time the mental attitude of aversion was held by Paul.

Given this mental aversion for a generic damaging process, we can actually model another situation, in which ceiling₀ has been heavily painted with a poisonous paint which could impact Paul's health if he passed close to it, given the paint can release volatile particles in the air. The same object, ceiling₀, and the same latent disposition of aversion, can explain several risks in this way. In the scenario in which the ceiling is both unstable and poisonous, aversion₀ can be intentionally directed to both harmful realizations of damaging by collapse and damaging by poisoning, since averting bodily damage is generic enough to comprise them both. For sure, we could model another agent, more selective than Paul, who only averts being damaged by the collapse of something from above, a very specific process, and so the poisonous ceiling would not lead to a risk for this selective agent, since they would not care. The lesson to be learned is that the intentional direction of aversion determines what is a risk or not.

Instead of averting the realization of a risk role, consider if we had said that Paul averted a process of collapsing of ceiling₀ which is the realization of a disposition, not of a risk role: such a process could happen even when Paul was miles away from ceiling₀, with no possibility of being hurt by it. He might actually feel some schadenfreude and rejoice at the sight of a collapsing building, for all we know. Maybe Paul likes watching videos of collapsing buildings, so this kind of process is not averted in itself, but only because it brings about a process of damaging Paul's health. This is an important distinction between the realizations of instances of *Risk*⁵ and *Risk*⁶, as well as a virtue of modeling risk as the latter, as it grasps what is really at the core of the conative states of an agent.

Risk roles are externally grounded properties in the sense that they exist in virtue of something else than the entity they inhere in. The risk hazard₀ is not there just because of ceiling₀, but because of some complex situation of an agent desiring something, which ontologically grounds it. With this in mind and having found all the suitable entities to express a situation of risk, we can finally clarify the “context” that we introduced earlier and understand better the entities and the connections present there. The objective side of risk that we have modeled first, with physical interactions between the parties involved, has now been articulated with the subjective side foreshadowed at the beginning. Paul’s mental disposition aversion₀, which is

<footnote n="4">⁴The authors thank John Beverley for this suggestion about intentional objects in OWL following BFO.</footnote>
intentionally directed towards a class of damaging processes,
grounds the existence of the risk role $hazard_0$ in ceiling$_0$.

Which intentional objects are targeted by the mental attitude
determines which and how many risks there are, so outside of
our example, if Paul also cared for its clothes and not just his
health, which could be ruined by the falling debris of ceiling$_0$,
a second risk, let's say $hazard_1$, would pop out into existence.
Such risk would be grounded in a new mental attitude such as
aversion$_1$, that would be intentionally directed towards a class
of processes of clothes being ruined.

V. TOWARDS A DEFINITION OF RISK

So far, we have illustrated our framework with some specific
instances in a very particular situation that enabled us to
illustrate the agent-relativity of risk. We can now present the
framework of risk as a role in Fig. 2. Note that we depicted
the case in which $ceiling_0$ actually falls during the collapsing$_0$
process and $hazard_0$ is realized in damaging$_0$, but such pro-
cesses might never occur. Moreover, to improve readability,
the relations participates_in and is_directed_towards have been
omitted.

<figure><img src="image_3.png" /><figcaption>Fig. 2. *Risk* as a BFO:Role</figcaption></figure>

Now, we abstract away from this particular scenario and its
instances to address risk more generally. The bearer of a risk
might be a BFO:Object (think about a knife), or other kinds of
BFO:Material entity, such as a body of water (e.g. in a flood)
or instances of more specific BFO categories (consider the risk
that a flock of birds, which is a BFO:Object aggregate, would
attack a human). It is also important to consider that bearers
of risk must be causally effective in producing the unwanted
consequence an agent would avert, which supports the choice
of a BFO:Material entity as the bearer of a risk, and that
such bearer must also have some specific BFO:Disposition.
Finally, the entity that averts the realization of the risk could
be an agent, like in our example, or a group of agents, like in
the case of an entire population threatened by war (we do not
discuss here whether such a group of agents would form an
agent at another level).

Now, are these entities and relations enough to define risk?
Arguably, some elements in our definition of risk might be too
specific and unnecessary. Indeed, some risks might relate to
teleological aspects that are more general than agents aversion
- consider e.g. the risk for a plant to die when set aflame:
burning would be the physical process involved, which is bad

only within the perspective of the goal of the plant to stay
alive. But it is debatable whether plants can desire or avert
anything. Therefore, the conative approach might have to be
generalized to also comprise this plant example.

Another element hinting towards a more general definition
of risk, that we cannot elaborate here, is the possibility for
non-material entities to bear risks. It is still to be determined if
plausible risky situations like a financial loss or a cyber-attack
only involve material entities, or if the source of damage could
have a different nature.

Given these considerations, we propose the following
sufficient (but not necessary) conditions for risk:

If: (i) r is a role &

(ii) r is externally grounded in an aversion that an agent or
group of agents have towards the possible realizations of the
role,

then r is a risk.

In case risk will be discovered to be only agenteive and the
risk bearer always material, then the condition above would
actually be necessary and sufficient and constitute a definition.
This shall be investigated in future work.

VI. CONCLUSION AND FUTURE WORK

To conclude, we have explored a novel way of under-
standing risk as a BFO:Role, after considering a similar
approach which categorized it as a BFO:Disposition. In order
to complete our modeling, we made use of realizable entities
in BFO, opening the way for a future ontology of risks as
roles. We proposed a sufficient condition for risks: future
work should inquire whether this is also a necessary condition,
or how it could be refined into a necessary and sufficient
condition. A limitation of this exploratory investigation was its
general character, and the lack of competency questions from
domain experts to evaluate the model. Future work should
also clarify the nature of a damaging process, what entities
can be damaged and what is the output of damaging, since
it might involve more considerations on negations, absences
and realizable entities. Our risk ontology will need to be
connected with risk probabilities (as started in [9] and [31])
and other relevant quantities: we merely covered qualitative
possibilities so far, but the quantification of risks often involves
probability measures and severity degrees. The ontology of
risk propagation should also be investigated, where material
entities can acquire and lose risk roles in a chain of causal
processes. Furthermore, it will be important to evaluate this
ontology of risk with real data and show how it can structure
the information present in risk registers for better clarity and
interoperability.

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