essences of sets are grounded in a similar way. In turn, the generalization that all sets
essentially have their members is fully grounded in the conjunction of the particular
essential claims. Like thefirst alternative, the second alternative appeals to modes of
being to ground facts about essences, but in other respects the grounding structure
is inverted.
9.7 Is It Always Part of the Modal Essence of
Things That They Have Their Mode of Being
(or Modes of Being)?Suppose the strict essence of a thing is always a proper subset of the modal essence of
a thing. If there are some entities that either could have had a different mode of being
or could have existed in a different way, then these entities have neither their mode of
being nor their degree of being as a matter of strict essence. And perhaps it is never
the case that the mode or degree of being of a thing is encapsulated in its strict
essence even if it is modally essential to that thing. For these reasons, I will focus here
on the question of whether all entities are such that it is modally essential to them
that they have either the mode of being or degree of being that they have.
It is impossible to satisfactorily answer this question without having settled some
first-order ontological questions and questions in the metaphysics of modality.
But it’s probably fair to say that our initial inclination is to answer negatively. How
could something change its mode of being, which is tantamount to changing
ontological category?
One of the most fascinating metaphysical doctrines discussed in Robert Pasnau’s
recent book,Metaphysical Themes, is the doctrine that God has the power to change
the mode of being of a mere“inhering accident”—something that in its current
manner of being can exist only in something else—to a mode of being such that this
very same entity can then exist as a free-standing being existing in its own right.^98
Pasnaufinds the idea that objects could undergo a change of their manner of existing
to be incredible, and suggests that there is no good precedent or analogy for this view.
Briefly, the main motivation for this view is the problem of the Eucharist—and you
might think that if we need to appeal to a miracle to justify something incredible, so
much the worse for the alleged possibility.^99
However, there are less divinely motivated metaphysical schemes on which change
of mode of being is more plausible. Consider a version ofpossibilismaccording to
which the difference between the actual and the possible is a difference in mode of
(^98) See Pasnau (2011: 188–90). See also Pini (2005: 70–1).
(^99) Jeff Brower has suggested another interpretation of how the medievals understood the Eucharist:
rather than attributing to them the view that an entity enjoys a change of mode of being, it attributes to
them the view that accidents never hadbeing-into begin with, but instead were merely disposed to be
instantiated by substances.