## 1. Metaphysical explanation as a form of non-causal explanation



To help us focus in on the topic at hand, contrast examples
(1)-(4) above with familiar examples of *causal*
explanation--for instance, the disappearance of a puddle through
evaporation because of the warmth of the surrounding air. What makes
this an instance of explanation is a matter for debate, although a
good enough approximation for our purposes is that it turns on how (in
this case causal) explanation works. As Lange puts it: a causal
explanation



> 
> 
> derives its explanatory power by virtue of supplying relevant
> information about the explanandum's causes or, more broadly,
> about the world's network of causal relations. (Lange 2016:
> 18)
> 
> 
> 



A puddle's disappearance does not merely *coincide* with
the warmth of the surrounding air, but rather occurs *because*
of it, at least in part thanks to causal interactions between the two
systems over time.



In contrast, metaphysical explanations at least appear to work in a
rather different manner. (1) seems to work at least in part due to
some relationship between Socrates and the bust of him on the one
hand, and a fact about those two plus a further entity, a property, on
the other. Whatever that relationship is, it seems radically different
from ordinary causal ones, for instance in being synchronic rather
than diachronic. The same can be said about (2), which invokes a
synchronic relationship between a determinable property and its
determinates. Similarly, (3) seems to work at least in part due to how
the essential nature of a thing non-causally constrains what features
it can have, while (4) seems to work at least in part due to there
being no difference between being just and having a well-ordered soul,
which would appear to preclude any causal relationships between
them.



It is in the minimal sense above that all should agree with the claim
that metaphysical explanation is a form of non-causal explanation (see
Schaffer 2017: 303). Nonetheless, one must take care here in at least
three ways. First, metaphysical explanation should not be
*identified* with non-causal explanation. After all, there are
arguably many other forms of explanation besides metaphysical
explanation that are non-causal; we mentioned mathematical explanation
above. But this is not to say that metaphysical explanation has
*no* role to play in how to understand these other types of
non-metaphysical non-causal explanations. Take, for example,
Steiner's pioneering work on mathematical explanation, which
starts with the thought that "to explain the behavior of an
entity, one deduces the behavior from the essence or nature of the
entity" (Steiner 1978: 143). To the extent this works in the way
(3) above works, by invoking the notion of essence, to that extent
mathematical explanation involves a form of metaphysical
explanation.



Second, to say that metaphysical explanation is a form of non-causal
explanation does not mean that it is disconnected from the causal
realm altogether. Consider another example:



(5)
Socrates is in pain because the functional role of pain is
realized by the C-fibers firing in his brain.


A functionalist about the mind might offer (5) as a part of a more
comprehensive metaphysical explanation of the nature of pain and its
instances. And yet, (5) invokes causation in at least two places. For
one thing, the *explanans* of (5)--i.e., the fact which
does the explaining--invokes a type of causal process. In
addition, the *explanandum* of a metaphysical
explanation--i.e., the fact to be explained--can invoke
causation, as for instance would be the case were one to offer up a
metaphysical explanation of causation itself. Thus what makes a
metaphysical explanation non-causal is not that the explanans or
explanandum are *themselves* non-causal, but rather that the
relationship *between them* is. For another thing, (5) works at
least in part due to the relationship between the functional role of a
mental state and its realizer. So if this relationship itself consists
in some relationship between the causal powers of a mental state and
its realizer (perhaps the former must be a proper subset of the
latter; see J. Wilson 1999, Shoemaker 2001), then to that extent, (5)
derives its explanatory power from causal facts. But (5) does not
derive it *solely* from these, for presumably the relationship
between the causal powers of a mental state and its realizer is not
itself a causal one (in the case of Wilson and Shoemaker, it is the
*is a proper subset of* relation).



Third, although a useful starting point, it is not entirely
*uncontroversial* to say that every form of metaphysical
explanation is a form of non-causal explanation. Take (2), which many
take to be a case of
 metaphysical grounding,
 the relationship by which more fundamental facts somehow "give
rise to" less fundamental ones. Although most theorists classify
grounding as non-causal, A. Wilson (2018) argues that grounding is
literally a form of "metaphysical causation", from which
it would seem to follow that (2) is a form of causal explanation (see
 SS6.1
 below). Or take Bennett (2017: 61-62), who claims that
causation is an instance of what she calls "metaphysical
building", every instance of which is an instance of
metaphysical explanation (at least if understood as a wholly objective
phenomenon, rather than one requiring that certain epistemic
conditions hold; see
 SS5
 for more on realist vs. antirealist conceptions of metaphysical
explanation). Nor is our starting point, useful as it is, entirely
*unproblematic*. Consider another example:



(6)
The natural world began to exist because of the causal activity of
a supernatural being.


Does (6) count as a metaphysical explanation? It might seem to, given
a traditional conception of metaphysics as studying the "first
causes of things" (see the entry on
 metaphysics).
 And yet, it appears to work solely thanks to certain causal facts.
Both points can be reconciled with our framing so far. Whatever
"metaphysical causation" might be, surely it is not
causation *of the ordinary sort* that links sunlight to puddle
evaporation over time, which is all that we meant to emphasize by
characterizing metaphysical explanation as non-causal. And moreover,
whether to classify all explanations offered in metaphysics as
metaphysical explanations, rather than more narrowly as just those
that derive their explanatory power partly from non-causal factors, is
a matter of terminological decision not worth engaging with at length.
Clearly there is *some* important difference between
(1)-(5) as opposed to (6) in how they work, and that difference
seems to have something to do with the non-causal ways in which they
work. *That* is a topic worth investigating, not whether to use
"metaphysical" in the broader way or the narrower one.


## 2. Some putative varieties of metaphysical explanation



A classic argument for the existence of
*properties*--mind-independent abstract entities, such as
those invoked in (1), that can be shared by multiple
particulars--is that they are needed in order to metaphysically
explain the objective resemblances we find in the world (see the entry
on
 properties, especially SSSS3-4).
 Both Socrates the philosopher and the bust of him in our seminar room
are snub-nosed. However (so the argument goes), it cannot be a brute
fact that this is so; there must be something in virtue of which both
of these things, separated by space and time, are snub-nosed.
Specifically, (so the argument concludes), the fact that these two
entities share the same property metaphysically explains why they
resemble each other in this respect. Yet even if objective
resemblances *are*, in fact, metaphysically explained by the
sharing of properties by things that resemble--a big
"if", although let us suppose so for illustrative
purposes--it remains to be said what *kind* of
metaphysical explanation is to be envisaged here. Reflecting on
(2)-(4) reveals at least three varieties of metaphysical
explanation that have been the focus of recent work on the topic and
in terms of which (1) could be understood.



One option is to offer (1) as a *grounding* explanation. There
is considerable controversy over what grounding is, and (as we shall
see) how grounding and explanations are related and how grounding
explanations work. We can stay somewhat neutral in saying that they
typically work by citing more fundamental facts--in the case of
(1), a fact about property sharing--that in some sense
non-causally "gives rise to", "produces", or
"generates" less fundamental facts--in this case, a
fact of resemblance among particulars. We say "typically",
since one may count as grounding explanations those that merely
*provide information* about the grounds of a given fact
(presumably of some contextually relevant type; see SS5.4), rather
than by citing its ground directly, as in (1\*):



(1\*)
Socrates the philosopher, and this bust of him in our seminar
room, are both snub-nosed because they share some property or
other.


At any rate, to treat (1) and (1\*) as grounding explanations would be
to group them with (2), given a standardly held view, namely that
instances of the determinable-determinate relation are paradigmatic
instances of grounding.



Although recent interest in metaphysical explanation arose from a
renewed interest in grounding over the mid to late twentieth century,
grounding explanation is arguably not the only form that metaphysical
explanation can take. This point was recognized as far back as
Aristotle, who in the *Organon* and *Metaphysics*
discusses metaphysical explanations that work by citing facts about
"the what it was to be" of some target phenomenon (see,
e.g., *Posterior Analytics* 83a7; *Topics* 141b35; and
*Metaphysics* 1003b24, 1006a32, 1006b13), or what we would now
call its *essence*. Like grounding, there is controversy over
what essence is; unlike grounding, much less has been said about how
essence and explanation are related and how what might be called
*essentialist* explanations work. We can again stay somewhat
neutral in saying that they typically work by citing (or perhaps just
providing contextually relevant information about) part of what it is
to be some phenomenon, in terms of some other phenomenon (e.g., Fine
2015 and Koslicki 2012).



Offering (1) as an essentialist explanation would be to group it with
(3), which might suggest rather different truth conditions for (1)
than if it were offered as a grounding explanation. *Prima
facie* at least, (3) does not explicitly require that
Socrates's having a certain man as a father be a more
fundamental fact than him being the very individual he is. Moreover,
it is widely held that the grounds of a fact are modally sufficient
for it to obtain, but need not be modally necessary for it, while the
opposite is true for essence, which would place rather different
conditions on whether a claim like (2) is true as opposed to a claim
like (3). Although a number of recent accounts of grounding analyze it
in terms of essence (e.g., Correia 2013, Zylstra 2018), or vice versa
(e.g., deRosset 2013, Gorman 2014), others do neither (e.g., Fine
2012, 2015). As a provisional matter, we shall treat grounding
explanations as distinct from (yet perhaps related to) essentialist
explanations and leave open for now whether instances of the one imply
instances of the other.



A third option is to instead offer (1) as what we will call a
*reductive* explanation, which would be to group (1) with (4)
(see the entry on
 scientific reduction).
 Like grounding and essence, there is some controversy over what
reduction is, although somewhat more has been said about how reduction
and explanation are related and how reductive explanations work than
in the case of essence. We can again stay somewhat neutral in saying
that reductive explanations typically work by "analyzing"
or "breaking down" some phenomenon as "nothing more
than" another phenomenon. Although a number of recent accounts
of reduction analyze the notion in terms of grounding, or essence, or
both (e.g., Correia 2017; Fine 2001, 2015; Rosen 2015), others do not
(e.g., Dorr 2016, King 1998). So here too, as a provisional matter we
shall treat reductive explanation as distinct from (yet perhaps
related to) both grounding and essentialist explanation and leave open
whether instances of the one imply instances of the other.



We are not suggesting that this list of varieties of metaphysical
explanation is comprehensive. For instance, consider:



(7)
Socrates has Sophroniscus as a father because he essentially has
Sophroniscus as a father.


Although Glazier (2017) calls (7) an instance of essentialist
explanation, (7) appears to us to work in a different way than (3).
Unlike (3), (7) does not attempt to explain *what it is* for
Socrates to be the individual he is, or even *what it is* for
Socrates to have Sophroniscus as a father. Rather, (7) concerns
*why* Socrates has Sophroniscus as a father, and works by
citing a certain fact about the *status* of this
relationship--namely, that it is essential to
Socrates--which would presumably help to explain why Socrates
must be so. Glazier argues that explanations like (7) do not imply
corresponding grounding explanations, and thus explanations like (7)
are not grounding explanations. Yet there is a more general pattern
here. Even if one is skeptical of the notion of essence, one might
attempt to metaphysically explain why Socrates has Sophroniscus as a
father in terms of some other status of this fact; for instance, one
might appeal to the fact that it falls under a more general "law
of metaphysics", or one might simply appeal to the necessity of
this fact alone (see Kappes forthcoming).



We are also not suggesting that one must treat all of these (or other)
forms of metaphysical explanation as genuine. Nonetheless, they are
prevalent enough in both classic and contemporary metaphysics that an
account of metaphysical explanation that aims to be comprehensive
ought to either accommodate all of them or explain why they are not
genuine forms of metaphysical explanation despite initial
appearances.


## 3. Separatism vs. unionism about metaphysical explanation



Before, we said that metaphysical explanations "derive their
explanatory power" somehow from non-causal relationships. More
specific proposals about the nature and varieties of metaphysical
explanation diverge over which relationships those are, and how that
work is carried out. Any proposal, though, must confront perhaps the
most striking feature of *any* form of explanation, one that
seems even more surprising in the case of metaphysical explanation.
Metaphysical explanations seem to have one foot *in the
world*--something to do with the way it is (causally or
non-causally) structured seems to play a role. Metaphysical
explanations are *metaphysical*, after all (or so one might
think). Yet they seem to have another foot in our *thought and
communication about* the world--our desire for explanation
(even if not a natural one, as Aristotle claims) is at least in part a
desire to *understand*, to make the world *intelligible*
to ourselves and others, to *learn* the why and how of things
and what to *expect*, to satisfy our *curiosity*.
Metaphysical explanations are *explanations*, after all (or so
one might think). Yet how could metaphysical explanation be at once
metaphysical, but also a form of explanation?



Following Raven (2015), who applies the terminology to grounding and
grounding explanations in particular, approaches to this fundamental
question might be classified with regard to whether they take a
"unionist" or "separatist" line. Standardly,
*unionism about grounding and grounding explanation* is the
thesis that they are one: to be grounded just *is* to be
metaphysically explained in a distinctive way (e.g., Dasgupta 2014;
Jenkins 2013; Litland 2013, 2017; Raven 2012; Rosen 2010; Thompson
2016). (A unionist might also subscribe to the stronger thesis that
the expressions "grounded" and "explained in
such-and-such distinctive way" are, or at least ought to be,
used as synonyms, but that is not essential to how we understand the
view here.) Unionists thus owe some account of how the metaphysical
and explanatory elements of metaphysical explanation can be held
together in a coherent package, or else jettison one element or the
other. *Separatism about grounding and grounding explanation*
is the thesis that they are separate, yet grounding explanations
nonetheless "track", or are "backed" or
"underwritten" by, instances of grounding (e.g., Audi
2012, Schaffer 2016, Trogdon 2013). Separatists thus owe some account
of how that link keeps the metaphysical and explanatory elements of
metaphysical explanation from flying off in opposite directions. One
might think that the separatist about grounding explanation here
incurs no new debt, since separatists about *causal*
explanation must meet an analogous challenge. However, note that the
quasi-causal model of metaphysical explanation at play here is far
from the only way in which we might model metaphysical explanation
(see
 SS6),
 and also that to distinguish causation from causal explanation is
itself a substantive commitment.



In order to extend the unionist-separatist classification to
metaphysical explanation *in general*, though, some care must
be taken. First (and most obviously), those who believe that there are
two or more forms of metaphysical explanation need not be unionists or
separatists across the board. The extent to which one is a unionist or
a separatist should depend on what non-causal relations one takes
statements like (1)-(4) to derive their explanatory power from,
as well as on background assumptions about what kind of thing an
explanation is and what kinds of things it relates, or even whether
these statements ascribe relations at all on the final analysis. For
instance, we have spoken loosely of metaphysical explanations as
*truths* of a certain kind that can be discovered and argued
over; one might take this view, and add to it the claim that they are
truths involving a relation between facts. Such a view might preclude
one from being a unionist about, say, essentialist explanations like
(3), if one holds that they concern relationships that may involve
things that are not facts (e.g., Socrates and his father).



Second, a further complication is that there is an open question
whether the various non-causal relations by which metaphysical
explanations work must *themselves* "track" still
further relations. For instance, one might maintain that instances of
grounding must somehow track the relations of whole to parts,
determinable to determinate, role to realizer, set to members, or
others. Those with unionist sympathies must therefore be clear about
whether grounding explanations are to be identified with grounding or
with some non-causal relation that *grounding* tracks, while
separatists must be clear about whether grounding explanations work by
tracking grounding, or by tracking some non-causal relation(s) that
*grounding* tracks. Similar points hold for essentialist and
reductive explanations, if one holds the view that there are relations
that essence-accident and analysans-analysandum must
"track".



Finally, there are viable approaches to metaphysical explanation that
do not fit neatly in either the unionist or separatist camp as it is
standardly understood. For instance, Maurin (2019) notes a distinction
between those who believe that grounding is "by its
nature" explanatory, as opposed to those who maintain that (at
best) grounding has certain other features that make it apt to back
grounding explanations. Interestingly, the former view (which counts
as unionist on Maurin's classification) does not automatically
imply that grounding *be* grounding explanation (which is
required to count as unionist on Raven's classification). After
all, knowledge is by its nature true, but it does not follow that
knowledge is truth. Setting aside the less interesting question of how
one ought to use the term of art "unionism",
Maurin's proposal--when broadened to metaphysical
explanation in general; see Thompson (2019)--shows that there is
conceptual space to distinguish the metaphysical and explanatory
elements of metaphysical explanation yet without explicitly linking
them by appeal to a relation of backing.


## 4. Monism vs pluralism about metaphysical explanation



In
 SS2,
 we canvassed some *putatively* different forms of metaphysical
explanation. But how many are there *in fact*? Monists about
metaphysical explanation think that there is just one, whereas
pluralists think that there are many. There are various different
respects in which one might be a monist or a pluralist. For example,
one might think that metaphysical explanations derive their
explanatory power from any of a number of non-causal dependence
relations (e.g., Thompson 2019), but that all metaphysical
explanations derive their explanatory power in the same way. This
would be a pluralism in one sense, because various kinds of relations
produce metaphysical explanations, but a monism in another because all
metaphysical explanations have the same form. A more monistic spin on
such an account would hold that grounding relations produce
metaphysical explanations, but that there are various grounding
mechanisms (e.g., Trogdon 2018). If the source of some metaphysical
explanations is relational but the source of others is to be found in
the essences of things, this is another version of this type of
"lightweight" pluralism.



According to a more thoroughgoing pluralism, there are a number of
fundamentally different kinds of metaphysical explanation. Such a view
can be motivated in a number of ways that do not at first glance
presuppose particular views about whether relations of non-causal
dependence like grounding, essence, and reduction reduce to one
another. Litland (2013) and Richardson (2020), for instance,
distinguish between *how-explanation*, which tells us
*how* or *the specific way in which* something is the
case and *why-explanation*, which tells us *why* it is
the case at all. Bertrand (2019) further recognizes a class of
metaphysical explanations *by constraint*:
"top-down" metaphysical explanations which show how
particular instances fit into a general scheme. These different kinds
of explanation are plausibly elicited by the asking of different
questions.



In reply, the monist might deny that the asking of different kinds of
questions to elicit metaphysical explanations implies that we should
be pluralists. They might simply be different ways of asking for the
same kind of explanation, for example. Moreover, why-questions are
generally taken to elicit causal explanations but can sometimes also
be used to elicit metaphysical explanations. One might then insist
that whilst differentiating kinds of explanation requests by the
question asked can be a useful heuristic, it is not a perfectly
reliable method for distinguishing different kinds of explanation.


## 5. Realism vs antirealism about metaphysical explanation



In
 SS3,
 we raised a surprising tension in theorizing about metaphysical
explanation: at least initially, it appears at once to be about
*the world* (qua metaphysical) and about *how we think and
communicate about the world* (qua explanation). *Realists*
and *antirealists* about metaphysical explanation disagree
about how to resolve this tension. For realists, metaphysical
explanation is primarily (or even entirely) objective and
mind-independent. That is, there is some mind-independent fact of the
matter about what metaphysically explains what; what metaphysically
explains what depends on what the world is like, and not (or at least
not primarily) on how we think or talk about it. Those who deny this,
and think of metaphysical explanation as inescapably linked to how we
think and communicate, are antirealists.



One can be realists about metaphysical explanation to varying degrees.
An extreme realist view conjoins a realism about metaphysical
dependence relations (they are themselves completely objective and
mind-independent) with the view that metaphysical explanations
*just are* the relevant kinds of dependence relations. Most
philosophers do not think metaphysical explanation is quite like this.
An attractive, widely held view is that metaphysical explanations have
both a representational component and a worldly component, as is
commonly the case when people adopt a version of the separatist view
discussed above
 (SS3).
 So long as the worldly component of metaphysical explanation
(generally taken to be a non-causal dependence relation of some sort)
is itself objective and mind-independent, the relevant account of
metaphysical explanation is generally considered realist.



However, there is room to adopt a view of metaphysical explanation
according to which constraints on how this worldly dependence relation
and the relata it holds between are represented factor into whether or
not something counts as an explanation. For example, one might think
that an extremely complicated description of the relation between
particles could fail as a metaphysical explanation of the existence of
a table, because when related to subjects with our level of cognitive
sophistication, it is impossible for us to understand or to expect the
existence of the table on the basis of the relevant description. This
would seem a less than fully realist account of metaphysical
explanation, because whilst the explanation includes a worldly
component, its counting as a metaphysical explanation or otherwise
depends on psychological factors such as the cognitive sophistication
of its likely recipients.



There are various ways to resist the above account without giving up
on the idea that acts of metaphysical explanation might sometimes fail
on the basis of psychological factors. One might insist that a
metaphysical explanation is to be distinguished from an *act*
of metaphysical explanation, and that all that is required for the
latter is a true representation of worldly non-causal dependence.
Metaphysical explanations abound to various degrees of complexity
(etc.) and their existing and counting as metaphysical explanations is
not something constrained by pragmatic, epistemic, or psychological
factors. How well they fare in acts of explaining is another matter,
one that falls under the question of whether or not they are
*successful* explanations. A different way to resist is to
insist that all that is required for realism is that one component of
the explanation be objective and mind-independent, because whilst the
term "metaphysical explanation" refers to a representation
of a worldly relation, whether something counts as a metaphysical
explanation or not fully depends on the worldly component. (One might
motivate this sort of view by claiming that, e.g., grounding is the
essential component of any metaphysical explanation, but explanations
are representational entities and so strictly speaking it is a mistake
to describe the relation as an explanation, even though it alone does
all the explanatory work, so to speak.)



In contrast, antirealists about metaphysical explanation at the most
extreme end of the spectrum do not see any role for worldly dependence
relations (see, e.g., Dasgupta 2017 and Taylor forthcoming for
discussion). They might adopt the two-component view discussed above
and maintain that both the relation involved in metaphysical
explanation and how it is represented are conceptual matters (e.g.,
because they are antirealists about the relevant non-casual dependence
relations), or they might think that metaphysical explanation has only
one component. That component might be a conceptual relation or a
non-causal dependence relation understood in an antirealist way, or it
might be something more representational. For example, one might
follow Shaheen (2017) in taking the use of causal metaphors to be a
component of our talk about metaphysical explanation, while going
further than he does by denying that the metaphorical cause-like sense
of "because" used in metaphysics has objective,
mind-independent truth conditions. Or one might follow Thompson
(2019), who thinks of metaphysical explanations as answers to certain
kinds of questions. Both views are consistent with thinking that
non-causal dependence relations play a role in metaphysical
explanation (by being what certain kinds of because-claims are about,
or helping to make it the case that a particular answer to a question
is correct) but the relations are not themselves a component of the
explanation.



Norton and Miller (2019) present what they describe as a
psychologistic theory of metaphysical explanation; metaphysical
explanations have truth conditions that appeal to the dispositions of
agents evaluating the explanation, as well as necessitation relations
between the explanans and explanandum. Since these necessitation
relations are objective this is not an entirely antirealist account of
metaphysical explanation, but from the way in which mental states vary
between individuals it follows that metaphysical explanations are only
true or false relative to a particular context of assessment. It is
thus to be considered a broadly antirealist account.


## 6. Models of metaphysical explanation



A common strategy when trying to get to a grip of some phenomenon is
to model our understanding of its nature on some pre-existing and
well-established understanding of the nature of a (supposedly
relevantly similar) phenomenon. In this section we survey some
instances of this strategy by investigating attempts to model
metaphysical explanation as a kind of *causal*
 (SS6.1),
 *nomological*
 (SS6.2),
 *unificationist*
 (SS6.3),
 or *pragmatist* explanation
 (SS6.4).


### 6.1 Metaphysical explanation as quasi-causal explanation



That metaphysical explanation is *like* causal explanation is a
view with quite a few proponents today (though see Taylor 2018 for
some problem cases for this view). Mostly those who think it is, also
think that all or most metaphysical explanations track or are
grounding relations (see
 SS3
 above). According to these philosophers, more precisely, metaphysical
explanation is like causal explanation because grounding is like
causation (Fine 2012; Schaffer 2016, 2017; A. Wilson 2018). In what
sense grounding is like causation varies among proponents of this
view. According to Schaffer, grounding and causation, although similar
(because both species of the kind *directed determination
relation*), are distinct. According to Wilson, grounding and what
he calls "nomic causation" are both kinds of causation
(although of a rather different sort than ordinary causation; see
 SS2).
 On both accounts, metaphysical and causal explanation are alike
because grounding and causation resemble each other. One might however
think that metaphysical explanation is like causal explanation simply
because the relations those explanations track *play the same
role* vis-a-vis explanation. Fine (2012: 40) may be said to give
expression to something like this view when he states that:
"Ground, if you like, stands to philosophy as cause stands to
science". Holding this view is compatible with the relations
those explanations pick out being in all other respects different from
one another.



If grounding is, or is like, causation, what follows concerning our
understanding of the nature of metaphysical *explanation*? That
depends. One suggestion is that, if grounding is (like) causation, how
we understand the nature of causation (and grounding) somehow directly
translates into an account of the nature of causal (and metaphysical)
explanation. Some accounts of the nature of causation seem a better
fit than others for this type of "translation". If, for
instance, causation is understood along counterfactual or
interventionist lines, causation and causal explanation (and, is the
idea, by analogy, grounding and metaphysical explanation) seem
especially closely related (see the entry on
 causation: and manipulability
 and the entry on
 counterfactual theories of causation).
 On this type of account, a causal explanation amounts to laying bare
systematic patterns of counterfactual dependence. In interventionist
language:



> 
> 
> [T]he common element in many forms of explanation, both causal and
> non-causal, is that they must answer what-if-things-had-been-different
> questions. (Woodward 2003: 221)
> 
> 
> 



Schaffer (2016) proposes we model grounding "in the image of
causation" along counterfactual lines (see A. Wilson 2018, who
offers a similar model). More precisely, he suggests we understand
grounding via so-called *structural equation models*. These are
models which can be characterized using a structure (introduced by
Halpern 2000) featuring a set of exogenous (independent) variables, a
set of endogenous (dependent) variables, a set of (incompatible)
values representing contrasts (such that there is a function mapping
every variable to an at least two-membered set of values), a set of
structural equations (telling us how each endogenous variable is to be
evaluated on the basis of the values of other variables), and some
assignment of values to each exogenous variable. Schaffer thinks this
formalism is excellent for modeling directed dependency relations
generally, and so is equally fitting for modeling both causal and
metaphysical dependencies. All that needs adjusting when we move from
causation to grounding is some of our background understanding of
surrounding notions.



Schaffer is a separatist (see
 SS3).
 Causal and metaphysical explanation are in other words distinct from
the relations (causation and grounding, respectively) they track, and
it is important not to think that everything that is true about the
explanation side of things must be true of the relation side of things
(and *vice versa*). Schaffer *does* draw one rather
substantive conclusion from the analogy between causation and
grounding, however: that there is no *distinctive* notion of
*metaphysical* (as opposed to causal) explanation. There is
just explanation (simpliciter) and explanation can be backed by
causation, grounding or whatever other relations are apt to back
explanation (which, on his view, is the same as being apt to be
modeled using structural equations). Similarly, A. Wilson (2018)
thinks that a "major theoretical benefit" of regarding
grounding as metaphysical causation is that this accounts, in a
straightforward way, for the explanatory nature of grounding claims:
grounding explanations are a type of causal explanation, and they work
by identifying metaphysical causes. The result is a unified theory of
explanation, at least of explanations that work by tracking some
worldly relation (see
 SS4),
 according to which all explanation is causal explanation.



Against the account, a couple of things can and have been said. First,
just as there are important analogies between grounding and causation
(of the ordinary, run-of-the mill sort:
 SS1),
 there are *dis*analogies as well. This is accepted by both
friends and foes of the view. The question then is whether those
differences are serious enough to undermine the work the analogy does
in the account (proponents of the account, not surprisingly
don't think so; for some who do: see, e.g., Bernstein 2016,
Janssen 2018, and Roski 2021; see Ylikoski 2013 for a related view).
Another argument (due to Janssen 2018) against understanding
grounding, and hence metaphysical explanation, in terms of structural
equation models points to the representational status of models
generally. Deciding whether or not a causal model includes the right
variables (both in number and kind) to be able to represent the causal
structure of interest sometimes involves reference to what is
considered the theory that best captures the actual features of
particular (local) causal processes or mechanisms. These are typically
theories for which we have *a posteriori* evidence. Yet in the
case of grounding, these sorts of "evidence" for
model-aptness are not available. In fact, it is not even enough for
the grounding theorist to include all *possible* scenarios, it
seems the grounding theorist must countenance
*counterpossibles* as well. That this is so, is admitted and
defended in A. Wilson (2018). For those who think this is
unacceptable, however, this is a serious problem with the account.



Another way of exploiting the analogy between grounding and causation
is by modeling metaphysical explanation on so-called
causal-mechanistic explanation via modeling grounding on causation,
mechanistically understood (see the entry on
 mechanism in science).
 Something along these lines is suggested in Trogdon (2018). On this
view:



> 
> 
> some metaphysical explanations are representations of grounding
> relations as being instances of grounding mechanisms. (Trogdon 2018:
> 1296)
> 
> 
> 



The explanandum of a grounding-mechanical explanation is the obtaining
of a grounded fact, and just as we can causally explain a phenomenon
by providing a model of the inner workings of the mechanism that
produces it (see Machamer et al. 2000), we can metaphysically explain
why a grounded fact obtains by providing a model of how grounding
facts and facts they ground are connected. We explain *why* a
grounded fact obtains by revealing the metaphysical determination
relations--examples, provided by Trogdon, include set formation,
the determinate-determinable relation, functional realization,
constitution and mereological realization--that hold between the
constituents of the relevant facts. In other words: we explain
*why* a fact obtains via accounting for *how* it is
(mechanistically) grounded.



Can *all* metaphysical explanations be understood in
quasi-causal terms? Those who want to argue that they can have their
work cut out for them. They first need to explain how explanations
like our (3) and (4) can be modeled in this way. Perhaps more
surprisingly, some argue that this sort of account might not even work
as an account of all types of metaphysical explanation involving
grounding. It is generally thought that a conjunctive fact is grounded
in its conjuncts. Yet, unless we think of conjunction-introduction as
a (mechanistic) determination relation--something Trogdon
cautions strongly against (and others: see, e.g., Wilsch
2015)--this is grounding in the absence of a grounding
mechanism.



If it follows that conceptual or logical metaphysical explanations
work in a different way than other types of (grounding) metaphysical
explanation, then the unification gained by modeling metaphysical as
causal explanation is arguably contradicted by the
*dis*unification of metaphysical explanations of the
grounding-kind. If you think this is a problem, there are a couple of
different options available: you may, first, claim that, although
cases of "bare" grounding are bare in the sense that they
do not involve any *grounding*-mechanisms, they are not bare in
the sense that they involve *no* mechanism whatsoever. They do,
only the mechanisms they involve are not *grounding*
mechanisms, but rather *conceptual* or *logical*
mechanisms: mechanisms involving the conceptual and/or logical
analogue of the grounding determination relations. Another option is
to try to redraw the boundaries for what counts as a
*metaphysical* explanation and argue that cases of bare
grounding do not back *metaphysical* but rather other types
of--conceptual or logical--explanation (e.g., Kovacs 2017;
McSweeney 2020). This frees the proponent of the mechanistic view from
having to introduce different kinds of mechanisms but does not really
solve the problem of disunification. Alternatively, the proponent of
the mechanistic view could argue that, while there is metaphysical
explanation in cases of bare grounding, those are cases where
grounding doesn't play an essential role in the explanation
(grounding doesn't back metaphysical explanation). The result
would be an account of metaphysical explanation able to provide us
with a unified account only of such explanations which
*essentially* involve grounding. In view of the fact that many
believe that conceptual and logical explanation, for example, need to
be separately accounted for anyway, this should perhaps be
acceptable.



Thus, even if there is this interesting sense in which we can unify
quasi-casual metaphysical explanations and causal scientific
explanations, it is not clear whether all metaphysical explanation are
of this form, since at least on first glance there seem to be
exceptions--sometimes major exceptions--that fail to be
covered by this model. Whether this is considered a problem or not
will depend on whether or not one thinks there is a special value in
monism with respect to one's account of metaphysical
explanation, and to what extent one takes putative examples that do
not fit the mold are genuine.


### 6.2 Metaphysical Explanation as nomological explanation



Some have argued that metaphysical explanation ought to be understood
as a species of the kind deductive-nomological explanation. On this
view (see Hempel & Oppenheim 1948 and Hempel 1965) (scientific)
explanations are sound deductive arguments, featuring the following
ingredients (see
 scientific explanation, SS2):


1. *An initial condition*: An event of type *F*
obtains.
2. *A law statement*: For all events, if an event of type
*F* obtains, then an event of type *G* obtains.
3. *A conclusion*: An event of type *G* obtains.



This way of understanding the nature of (scientific) explanation does
not mention causation and is compatible with a Humean understanding of
laws of nature, for example one that takes laws of nature to be truths
that belong to any deductive system that best balances simplicity and
fit with the facts. In this sense, understanding explanation in
deductive-nomological terms can easily be combined with an antirealism
about such explanations, if the notions of best balance, simplicity,
and/or fit with the facts are understood partly in terms of how we
think or communicate (see
 SS5).
 Or the account can be understood as realist in nature, if, for
example, one's preferred account of the nature of laws of nature
is in turn realist (those proposed by Armstrong 1983, Dretske 1977,
and Tooley 1977 being one example).



Most of those who have argued that metaphysical explanation is
deductive-nomological have tended to defend a comparatively
"heavyweight" account of the (metaphysical) laws that
metaphysical explanations involve, and so have opted for a realist
separatist version of the account. Laws, on this view, are understood
as something more or other than the Humean regularities they entail,
and in at least some cases involve or reduce to facts about an
underlying "construction" relation or essence (e.g.,
Glazier 2016; Kment 2014; Wilsch 2015). For more on the nature of
"laws of metaphysics", see, e.g., Sider (2011: sect. 12.4)
and Rosen (2006; 2017). For a comparatively speaking less heavyweight
account of the nature of the laws that feature in metaphysical
explanation--one according to which such laws are nothing but
"counterfactual-supporting general principles" and
therefore "inclusive" in the sense of being neither
necessarily fundamental nor necessarily exceptionless--see
Schaffer (2017). See also Woodward and Hitchcock (2003).



Adopting a more heavyweight account of the nature of metaphysical
laws, and hence of metaphysical explanation, may come with a
metaphysical cost--for instance, if one takes them to be
ontologically basic entities, or if one takes the distinction between
laws and non-laws to be a primitive one. According to proponents of
such an account, this is a price worth paying. One important reason
why the traditional deductive-nomological account of (scientific)
explanation has few proponents today was that the symmetry of
deductive entailment in certain cases seemed to interfere with our
intuitions about the asymmetry of explanation (e.g., Lehrer 1974, who
gets the example from Bromberger's (1966) famous flagpole/shadow
example, see also the entry
 scientific explanation SS2.5).
 If the laws that explanation invokes involve or even reduce to
something which has direction (from more to less fundamental) already
built in, this problem is entirely avoided. Of course, if the account
is to be able to also cover metaphysical explanation in the sense of
essentialist explanation (see
 SS2
 above), the fact that the laws have direction already built in could
be considered a flaw rather than an advantage.



Finally, if metaphysical explanation is deductive-nomological (or
"covering law"), it seems that there is no room for
explanations of rare or one-off phenomena in terms of the mechanisms
that ground (or cause) them, even in cases where, had a similar
mechanism occurred, it need not have given rise to a similar
phenomenon (e.g., Taylor 2016). According to Trogdon (2018; see also
Anscombe 1971), it seems likely that some explanations *are*
one-off in this sense, from which it would seem to follow that, even
if some or most metaphysical explanations turn out to be deductive
nomological, this cannot be true of all of them. For an argument
against this conclusion--on the grounds that laws of metaphysics
can be indeterministic and that (like indeterministic laws of nature)
they can hence help explain rare events--see Wasserman
(2017).


### 6.3 Metaphysical explanation as explanation by unification



Unificationism is a view of scientific explanation that, although it
builds on some of the insights of the classic DN-model, extends and
refines that model by focusing, not on individual arguments, but on
those argument patterns which best unify the relevant phenomena. Its
core idea is that to explain is to derive as many conclusions as
possible from as few premises as possible, using as few and as
stringent argument patterns as possible. The fewer patterns used, the
higher the stringency. The greater the range of conclusions derived,
the greater the unification. The account (inspired by Friedman 1974)
was first developed by Kitcher (1981, 1989). For a good overview, see
the entry on
 scientific explanation (SS5).



In metaphysics, an account of explanation along something like these
lines can (as noted by Roski 2019) be found already in the work of
Bolzano. Recent attempts to adapt Kitcher's model to suit
metaphysical and not just scientific explanation include Kovacs (2020)
and Baron & Norton (2021) (see Bertrand 2019 for an account that,
although not couched in terms of unification, has a lot in common with
their views).



A unificationist account of metaphysical explanation is an account
according to which such explanations aim to unify the beliefs
implicated in metaphysical theorizing. On this view, roughly speaking,
a particular derivation is a metaphysical explanation just in case it
is an instance of an argument pattern that unifies metaphysical
beliefs. Several things can be said in favor of this view. If you are
no fan of grounding, the fact that it takes metaphysical explanation
to be something completely independent of whatever determinative
(grounding) relations there happen to be (or not), will count as a big
point in its favor. Another positive is the fact that it is an account
of metaphysical explanation that makes unusually good sense of the
link between explanation and understanding. Unificationism corresponds
to an intuitive way of thinking about understanding: we understand
better when we can derive large amounts of information from a fairly
small number of premises and a small number of argument patterns. This
is because the ability to do so suggests an ability to identify
connections between things; to fit things together. Yet the resulting
account is not (just) psychological. As Friedman points out,
explanatoriness remains in an important sense objective if "what
is scientifically comprehensible is constant for a relatively large
class of people" (1974: 7-8).



For those who think of metaphysical explanation as an entirely
objective and worldly affair the account will however remain highly
unattractive. Indeed, even those who think of metaphysical explanation
as partly representational--the so-called separatists--will
most likely not find it very appealing. Note, though, that some think
that metaphysical explanation can be *either* unificationist or
understood in terms of grounding (Bertrand 2019 is one example). If
so, although metaphysical explanation will become a less unified
phenomenon, the fact that it can make sense of both what Bertrand
(inspired by Salmon 2006) calls "top-down" and
"bottom-up" metaphysical explanation, should perhaps count
as a point in its favor.



Some further objections to the account--including, among other
things, the question of what should count as *the best*
systematization; if understanding metaphysical explanation in
unificationist terms means having to give up on the "impure
logic" of such explanations, and; if given unificationism,
logical truths will lack metaphysical explanation--are discussed
(and ultimately rejected) in Kovacs (2020). A classic objection to the
unificationist account of causal explanation, finally, is that it,
just like its close cousin the DN-account (see
 SS6.2),
 fails to make sense of the asymmetry of such explanations, at least
not without assuming causal realism. A similar objection may well be
available to those who combine unificationism and anti-realism about
metaphysical explanation. 


### 6.4 The pragmatics of metaphysical explanation



Pragmatic accounts of metaphysical explanation hold that whether
something counts as an explanation or not is context-dependent. This
goes deeper than thinking that explanatory *information* is
context-dependent; that there are pragmatic constraints on how much,
how little, or what kind of explanatory information to request or give
in a particular conversation is fairly widely accepted. It also goes
deeper than noting that which relation the term "explains"
picks out differs from context of utterance to context of utterance
(since, perhaps, one takes the term "understands" to be
context-sensitive in this way, and one takes the conferral of
understanding to be necessary to explanation). The thesis is rather
the far more controversial one that metaphysical explanation is
*itself* a context-sensitive phenomenon in the sense that the
factors relevant to evaluating the truth of a statement of
metaphysical explanation, once the context of utterance has settled
that statement's truth-conditions, involve facts about actual or
possible (types of) explanation givers or receivers, such as facts
about their interests, conceptual proficiencies, background knowledge,
and the like.



In the literature on causal explanation, the most famous proponent of
pragmatic explanation is van Fraassen (1980) who argues that
explanations are answers to why-questions. A fairly straightforward
analogue for metaphysical explanation would be to hold that
metaphysical explanations are answers to what-makes-it-the-case-that
questions. There are then various different ways in which aspects of
context become salient. First, the context might focus the question.
When we ask "What makes it the case that the ball is
red?", we will expect different answers depending on the
contrast class we had in mind (e.g., red rather than some other color,
or red rather than merely appearing to be red). Second, the context
also determines the kinds of answers that are acceptable, which might
differ based on (for example) the background knowledge of the
explanation-seeker and explanation-receiver. An artist will typically
have a far more finely-grained conception of what particular shade
makes a certain Rothko painting red than your average schoolchild
would, and so a particular answer might count as explanatory for the
artist but not for a child (who may not even possess the relevant
color concept).



There has, as of yet, been comparatively little discussion of
pragmatic accounts of metaphysical explanation in the literature. One
exception is Thompson (2019), who develops an account along the lines
described above, where metaphysical explanations are pairs of
context-sensitive questions and answers. Because the role of context
is ineliminable, there is no sense to be made of a notion of
metaphysical explanation free from pragmatic constraints. However,
Thompson accounts for the correctness of particular explanations (in
part) by appeal to worldly dependence relations, and so that
metaphysical explanation is pragmatic does not imply that it is wholly
unconstrained by worldly dependence. A different kind of pragmatic
theory of metaphysical explanation is defended by Miller and Norton
(2017). Their "psychologistic" account of metaphysical
explanation locates the truth conditions for metaphysically
explanatory claims in the psychological states of the agents
evaluating the relevant "because" claims, alongside
worldly necessitation relations. The relevant psychological states are
dispositions towards particular beliefs, which are expected to vary
between individuals. Claims about what metaphysically explains what
are thus only true relative to a specific (type of) context within
which the claim's truth is being assessed.


## 7. The scope of metaphysical explanation


### 7.1 Metaphysical explanation outside of metaphysics



Thus far, we have discussed the *nature* of metaphysical
explanation, but have kept silent on what its *extent* might
be. At first glance, facts of all sorts inside metaphysics and out
seem to at least in principle admit of metaphysical explanation. In
this section, we discuss recent applications in ethics, philosophy of
mind, and philosophy of social science respectively.



First, ethics. In Plato's *Euthyphro*, the eponymous
Euthyphro is asked by Socrates to consider the following question: Is
that which is pious loved by the gods because it is pious, or is it
pious because it is loved by the gods? (*Euthyphro* 10a). This
is a very early example of a request for a metaphysical explanation,
for the connection between piety and being loved by the gods imagined
in the second horn does not seem to be a causal connection, but a
constitutive one (although what Plato means by "because"
in the first horn, and the overall structure of Plato's
argument, remains controversial). Requests for explanation abound in
moral philosophy: one of the key aims of first-order moral philosophy
is to *explain why* the right actions are right and the wrong
ones are wrong (Fogal & Risberg 2020), and of metaethics is to
systematize those explanations. Fine (2012: 37) distinguishes between
three different explanatory relations: metaphysical, normative, and
natural, apparently suggesting that normative explanations and
metaphysical explanations are different kinds of explanation. However,
explanations in the moral realm (e.g., that an action is bad because
it causes pain, or that something has intrinsic value just in case it
is valuable in virtue of its intrinsic properties) are often
considered paradigm cases of metaphysical explanations. Berker (2018),
who is a unionist, argues at length that it is metaphysical grounding
(and thus metaphysical explanation) that is at issue in moral
philosophy.



Second, philosophy of mind. Although there has been limited systematic
discussion of metaphysical explanation in the area, considerations
about metaphysical explanation inform some of the most fundamental
questions in the discipline, such as how it could be the case that
consciousness exists. It is fairly common for the grounding literature
to mention by way of elucidation of the notion of grounding that we
might think of mental facts as grounded in the physical facts. This
example is supposed to be compelling because of the attractiveness of
the idea that physical facts determine and metaphysically explain the
mental facts, and grounding is a *prima facie* appealing notion
with which to characterize the relationship between the mental and the
physical precisely because of its explanatory nature. This idea is
made more precise in the development of *grounding physicalism*
(see, e.g., Ney 2016; O'Conaill 2018; Rabin forthcoming-a,
forthcoming-b; Schaffer 2021), though this new version of physicalism
has not been met with universal approval (see, e.g., Melnyk 2016; J.
Wilson 2018).



For physicalists in the philosophy of mind who maintain that the
mental is grounded in, supervenient on, or identical with the
physical, there is a pressing need to explain what makes it the case
that some particular phenomenal feel should be associated with a given
physical state (see, e.g., Chalmers 1996; Levine 2001). This
explanatory gap is an epistemic one, and so there are two ways we
might proceed. The first is to insist that unless the explanatory gap
has been closed, we do not have a metaphysical explanation of the
mental in terms of the physical. The second is to allow that we might
have a metaphysical explanation without a corresponding epistemic one.
Schaffer (2017) argues that grounding, and the metaphysical laws that
provide the framework for grounding, close the explanatory gap between
the mental and the physical (and many more besides). Rabin (2019)
disagrees, claiming that the gap between consciousness and physical
fundamentalia has a special status, persisting even if we grant that
the former is metaphysically explained by the latter.



Third, philosophy of social science. Theorizing about the nature of
social reality at least partly involves metaphysically explaining
social reality. Debates between (methodological) holists and
individualists, for example, concern whether social activities and
events are to be explained by appeal to macro-level (social)
phenomena, or by the thoughts and actions of the individuals that,
most agree, make up or ground those social phenomena (see, e.g.,
Popper 1945; Watkins 1952). The metaphysically explanatory nature of
social theorizing has not always been appreciated. This is brought out
in the distinction between explanatory and ontological individualism
(Lukes 1968). Explanatory individualism is the thesis that social
reality is best explained in terms of individuals, their thoughts and
interactions. Ontological individualism, on the other hand, holds that
social reality consists in or is exhaustively determined by
individuals, their thoughts and interactions. If, however, social
reality is or is grounded in individuals and their interactions,
social reality is metaphysically explained by those individuals and
their interactions (Epstein 2015). Both these theses are theses about
explanation.



Metaphysical explanation is also relevant when considering the
existence and nature of social kinds. According to Haslanger (2012),
for example, being a woman amounts to occupying a certain (subordinate
and hence oppressed) position in a social hierarchy. This type of view
gives rise to Euthyphro-like queries of the kind: is *x* a
woman because she occupies a certain position in an oppressive
structure, or does she occupy this position because she is a woman?
(see Asta 2010). According to some philosophers involved in
this debate, how you answer this question will decide if your account
is realist (Barnes 2017) or deflationist (Diaz-Leon
2018). Haslanger herself has argued that the account is best
understood as something in between. Against the
"deflationists", she is an extensionalist about meaning,
from which it follows that it would make no sense to say that we have
to sort out what the word means before determining its extension.
Against the realists, Haslanger sometimes talks as if she rejects the
idea that reality is hierarchically structured and holds instead that
the natural world is neither explanatorily prior to nor ontologically
more fundamental than the social world (pace, e.g., Schaffer
2017).


### 7.2 Do all facts admit of metaphysical explanation, or none?



Abstracting from specific putative applications of metaphysical
explanation outside of metaphysics proper, can one say in more general
terms what the extent of metaphysical explanation is? On one extreme,
proponents of the famous
 "principle of sufficient reason"
 contend that everything (or
everything of a certain sort, e.g., contingent facts) has an
explanation of some form or other, and Dasgupta (2016) has prominently
developed a version of the principle regarding *metaphysical*
explanation, specifically *grounding* explanation on his view.
Notably, Dasgupta distinguishes between two ways that metaphysical
explanation might be limited in extent. Call a *substantive*
fact one that is "apt for being grounded", in the sense
that



> 
> 
> the question of what grounds it can legitimately be raised and admits
> of a sensible answer (an answer that either states its ground or else
> states that it has none),
> 
> 
> 



and call a fact *autonomous* just in case it is not
substantive, and thus is one for which "the question of why it
obtains does not legitimately arise" (2016: 383).
Dasgupta's version of the PSR is then the claim that
"*every substantive fact has an autonomous ground*"
(2016: 84).



Broadening Dasgupta's distinction, there are two questions about
the scope of metaphysical explanation to consider. First, which (types
of) facts have metaphysical explanations--all, none, or something
in the middle? Second, of those that lack metaphysical explanations,
which (types of) facts are not apt to be metaphysically explained at
all? Dasgupta suggests that facts about essence are autonomous facts
(2016: 385). Other philosophers have challenged the idea that facts
about essences are ungrounded, and so have opened the door to facts
regarding essences having metaphysical explanations (see Tillman 2016,
Glazier 2017, Raven 2021).



On the other extreme, one might maintain that no fact is apt to be
metaphysically explained. One type of worry is that notions thought by
some to be constitutive of metaphysical explanation, such as grounding
and essence, are somehow defective (see the entry on
 metaphysical grounding SS8
 and the entry on
 essential vs. accidental properties SS5).
 Another type of worry is that metaphysical explanations would compete
with scientific, mathematical, and/or other forms of explanation in a
manner that render metaphysical explanations objectionably
superfluous. Jeff Engelhardt (2016) develops this line of thought and
argues that many philosophers are implicitly committed to an
objectionable sort of overdetermination involving metaphysical
explanation. The sort of overdetermination he has in mind regards
cases where something seems to have a sufficient causal explanation as
well as a sufficient metaphysical explanation. For example, for any
given house, that house exists both because it was caused to exist
(causal explanation), as well as because it is grounded in its parts
(metaphysical explanation). Perhaps the best solution to the problem
which we can come up with, Engelhardt suggests, is that in cases such
as this one the cause in question (*C*) causes the grounds of
the house to obtain, but *C* does not cause the house to exist.
In this case, while *C* does explain why the house exists, it
does not *causally* explain why the house exists. Rather,
*C* causally explains why the parts of the house are configured
in such-and-such a manner, and those parts being configured in that
manner in turn grounds the existence of the house.