Introduction
Within the philosophy of mind, there are
several nuanced views that can be held concerning anthropology and the
constitution of man. Even within views that allow for immaterial human souls,
there are widely varying positions held. Particularly contentious has been the
view of substance dualism (SD), also referred to as Cartesian dualism.[1] If
SD is true, then, obviously, physicalist theories of mind are false; with it,
likely, goes naturalism. Thus, SD can be a valuable tool in the arsenal of the
Christian philosopher. Second, traditional Christian doctrine has been such
that an immaterial soul is required for the intermediate state: SD can account for
this, and in a way that seems intuitive and natural for the believer. Finally,
we can have comfort in the death of loved ones knowing they are with the Lord.
But are there any good arguments for SD? J.P. Moreland has proposed a
particular version of a modal argument for SD for consideration. It is my
contention that Moreland’s modal argument for SD can be justifiably held in the
face of contemporary objections. First, I state the argument formally and
explain the support behind each of the premises. Then, I consider three major
objections to the argument and provide responses that, while not conclusive,
provide reasons to think SD might survive. Finally, I give applications that
may be applied for believers and the local church.
The
Argument Stated
In Moreland’s book The Soul, he offers several arguments for SD. The modal argument is
a particularly interesting example in that it seems to establish strongly the
conclusion of SD. This is notable since, typically, arguments that purport to
establish SD in reality do little more than show that physicalism is false.
While doing so is surely valuable, and leaves the door open for SD, it is also
consistent with types of holistic dualism (and Moreland generally wants to do
more than this). This modal argument is as follows:
1.
The
law of identity is true: If x is
identical to y, then whatever is true
of x is true of y and vice versa.
2.
I
can strongly conceive of myself as existing disembodied.
3.
If I
can strongly conceive of some state of affairs S that S possibly
obtains, then I have good grounds for believing that S is possible.
4.
Therefore,
I have good grounds for believing of myself that it is possible for me to exist
and be disembodied.
5.
If
some entity x is such that it is
possible for x to exist without y, then (i) x is not identical to y,
and (ii) y is not essential to x.
6.
My
body (or brain) is not such that it is possible to exist disembodied, i.e., my
body (or brain) is essentially physical.
7.
Therefore,
I have good grounds for believing of myself that I am not identical to my body
(or brain) and that my physical body is not essential to me.[2]
The initial premise, (1), is relatively
uncontroversial—if interpreted in a very specific way. (1) is often referred to
as Leibniz’ Law, named for Gottfried Leibniz. Much of the recent discussion has
centered around the fact that (1) seems to preclude any idea of contingent
identity.[3]
Contingent identity is the idea that there may be two objects, x and y, that
are identical objects despite the fact they have one or more differing
contingent properties. For an example, consider Socrates. In this actual world
(call it W), Socrates is, say,
five-foot-four in height. However, consider a nearby world, W’, where Socrates is five-foot-five. We
say that the Socrates in W is the
same as (or identical to) the Socrates in W’.
Yet, strictly speaking, on (1) above, this is false. This is because
Socrates-in-W has a property that
Socrates-in-W’ does not, namely being
five-foot-four, and hence they are not identical.
There are two proposed solutions to this
problem—one of which will require a slight adjustment to the wording of the
premise, and the other an understanding of an underlying metaphysical concept.
The first solution is to adjust the Law by accounting for worlds and times.
This approach is taken by Thomas McCall. He lists his principle as follows: “For any objects x and y, if x and y
are identical, then for any property P, any world W, and any
time t, x has P in W at t if and only if y
has P in W at t.”[4]
This
solution is helpful for our Socrates problem, since the property of being
five-foot-four at t in W would be had by both Socrates’, and
the same thing goes for the property of being five-foot-five at t
in W’. Another way to view the issue would be counterfactually: If it
were the case that W were the actual world, then it would be the case
that Socrates is five-foot-four.
The
second solution, I think, spells out the underlying metaphysical reasoning
behind the first solution. It relies on Alvin Plantinga’s theory of creaturely
essences. For every concrete particular agent, such as human persons, there is
an abstraction called a “creaturely essence” that contains all and only the
essential properties of that essence. The creaturely essence is a set of
essential properties that, for Plantinga, is itself a singular property (for
Socrates, he calls it Socraeity).[5]
This property has what he calls “world-indexed properties,” where such a
property P is world-indexed just in case “an object x has the
property having P in W in a world W* if and only if x
exists in W* and W includes x’s having P.”[6]
Essentially, world-indexed properties for creaturely essences accomplish the
same thing as McCall’s solution, even while preserving the initial formulation
of (1). This is because the properties discussed have their contingencies in
the worlds in which they appear and all belong to the same creaturely essence.
Either way, a relevant version of the law of identity stands, and this is
crucial to Moreland’s argument.
Even
more than (1), (2) will be the primary point of controversy in this modal
argument for SD. For a reminder, (2) is: “I
can strongly conceive of myself as existing disembodied.” This “strong”
conception is needed, and not what Stewart Goetz would call “weak” conception.
To weakly conceive of something is, as Goetz states, a “failure to be aware.”[7]
Thus, if (2) were to be weak conceivability, it would express no more than that
one does not see any reason to think he is identical to his body, or that there
is nothing in his awareness such that disembodiment is impossible. Such weak
conceivability will not yield the conclusion Moreland draws; hence, he employs
a strong conceivability. This strong conceivability is a positive; it is the
ability to be aware that one can exist disembodied.
What reasons does Moreland provide for
thinking (2) really is true? First, he draws relevant analogies. We strongly
conceive of ourselves in particular ways that present themselves to our
reasoning all the time. For example, we know that we are not the type of thing
that can be subject to gradation (we are a unified individual, and not
something that can become two-thirds of a person). Similarly, I can persist through change and time,
and I am not merely the collection of disparate temporal or property-divided
parts.[8] If
this is so, then while we do not have a knock-down argument supporting (2), we
do have reason to think that we could justifiably hold (2), or that we really
can conceive of how we are with respect to identity or constitution, through
relevant modal intuitions.
Second, Moreland argues directly from
these modal intuitions. He and William Lane Craig write, “We are aware of our
own self as being distinct from our bodies and from any particular mental
experience we have. We simply have a basic, direct awareness of the fact that
we are not identical to our bodies . . . rather, we are the selves that have a body and a conscious mental
life.”[9]
This direct modal acquaintance will provide the one who has such an awareness
(that he can be distinct from his body) with prima facie justification for (2).
What about (3)? For a reminder, (3) is:
“If I can strongly conceive of some state of affairs S that S possibly
obtains, then I have good grounds for believing that S is possible.” This seems innocuous enough. This kind of move is
made all the time in discussions on possible worlds or other imaginative
alternate scenarios. Although he offers it in defense of (2), Moreland makes
two points that apply to (3). First, he discusses near-death experiences.[10]
While often dismissed without a second thought, Moreland’s point is that if
people’s experiences are even possibly true, then a disembodied existence is
possible (which is enough to establish his point). Second, Moreland uses other
modal conceptual scenarios to support (3), including that alien life on other
planets is at least possible (because he can conceive of it).[11]
(4) is an entailed conclusion, following from
(2-3). (4) is stated as follows: “I have good grounds for believing of myself
that it is possible for me to exist and be disembodied.” This seems fair
enough, given Moreland’s argumentation so far.
(5) is stated as a nearly self-evident
truth: “If some entity x is such that
it is possible for x to exist without
y, then (i) x is not identical to y,
and (ii) y is not essential to x.” Conclusion (i) follows from the law
of identity as stated in (1), and conclusion (ii) comes from an analysis of
what it means to be essential. If y
is essential to x, then in no
possible state of affairs does x
exist without y (since that is what
it means to be essential).
(6) is just a definitional premise, and
should not be questioned on physicalist grounds: “My body (or brain) is not
such that it is possible to exist disembodied, i.e., my body (or brain) is
essentially physical.”[12]
Of course, because of everything that has
come before, (7) is the final conclusion of the argument for SD: “I have good
grounds for believing of myself that I am not identical to my body (or brain)
and that my physical body is not essential to me.” Notice Moreland needs both
sides of (7) in order to establish the truth of SD. The first part of the
conjunction establishes the falsehood of physicalism, while the second does
away with views that require the body as essential to the person. Can
Moreland’s argument survive various objections that can be lodged against it?
In the next section, I explain and examine three major objections to this modal
argument.
[1] While it is true that
any form of dualism that espouses more than one substance can on this basis
qualify as a type of substance dualism, this paper will refer to Cartesian
dualism as SD, and other forms of substance dualism (such as Thomistic
hylomorphic dualism) as “holistic dualism” or some other nuanced term.
[2] J. P. Moreland, The Soul: How We Know It’s Real and Why It
Matters (Chicago: Moody Publishers, 2014), 125-26.
[3] Pablo Cobreros, Paul
Egre, David Ripley, et al., “Identity, Leibniz’s Law and Non-Transitive
Reasoning,” Metaphysica, Vol. 14, No.
2 (October 2013:), 253-64.
[4] Thomas H. McCall, “‘I am my Body?,’” Philosophia Christi, Vol. 17, No. 1 (November 2015:), 208.
[5] Alvin Plantinga, The Nature of Necessity (New York:
Clarendon Press, 1974), 71-72.
[6] Ibid., 63.
[7] Stewart Goetz,
“Substance Dualism,” In Search of the
Soul, Joel B. Green and Stuart L. Palmer, eds. (Downers Grove, IL: IVP
Academic, 2005), 44.
[8] Moreland, 127.
[9] J.P. Moreland and
William Lane Craig, Philosophical
Foundations for a Christian Worldview (Downers Grove, IL: IVP Academic,
2003), 238. Of course, here it can be wondered why, then, there is any argument
to be made at all. Perhaps one could respond that the modal intuition that
leads to (2) entails we are souls, and the argument may be needed to expose
this entailment in particular cases. As such, the argument is really meant to
reveal implications of already-held beliefs or modal intuitions, and so falls
in-between a knowing and showing style of argumentation.
[10] Moreland, The Soul, 127.
[11] Ibid., 125.
[12] It is true the monist
who is an idealist could object to this, but a number of underlying assumptions
made in this dialectic is that either some kind of physicalism is true, or some
kind of dualism (holistic, SD, or otherwise). Thus, while interesting and
worthy of attention, this paper will not deal with idealism.
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