University at Buffalo Neuroethics Advance of Medicine & Technology Discussion

Using the material from Gazzaniga and Shoemaker, offer an analysis of the earliest stage of development at which a biologically human organism plausibly has intrinsic moral value. If you argue that this earliest point is conception, explain two arguments for why that is a bad answer and offer replies to those arguments. If you argue for a point later than conception, explain one argument that supports an earlier stage and one argument that supports a later stage, and for each of these arguments, offer a reply.

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Florida State University Department of Philosophy
Embryos, Souls, and the Fourth Dimension
Author(s): David W. Shoemaker
Source: Social Theory and Practice, Vol. 31, No. 1 (January 2005), pp. 51-75
Published by: Florida State University Department of Philosophy
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Embryos, Souls, and the Fourth Dimension
Human embryos are not mere biological tissues or clusters of cells; they are the tiniest of
human beings. Thus, we have a moral responsibility not to deliberately harm them
Why would someone believe that an embryo is a human being, albeit an
exceedingly tiny one? It is merely a cluster of cells, after all, and it in no
way resembles ordinary human beings like you and me, entities with the
functional abilities to think, feel, locomote, laugh, love, and actually be
seen by the naked eye. Furthermore, even if embryos were human be
ings, why would that fact alone generate a moral obligation on our part to
refrain from harming them? In other words, what precisely is it about
human beings that warrants their moral protection?
These sorts of questions have played a major role in the longstanding
abortion debate, of course, which nevertheless generally focuses not on
the embryo but on the fetus. Specifically, abortion theorists typically
want to figure out (a) what the ontological status of the fetus is, that is,
into what category of the world it fits, and (b) what its ontological status
implies, if anything, about its moral status, that is, how entities catego
rized-like-that ought to be treated.2 Fetuses, though, especially late-stage
‘Statement (1999) from Do No Harm: The Coalition of Americans for Research Eth
ics (Washington, D.C.), quoted in Ted Peters, “Embryonic Stem Cells and the Theology
of Dignity,” in Suzanne Holland, Karen Lebacqz, and Laurie Zoloth (eds.), The Human
Embryonic Stem Cell Debate: Science, Ethics, and Public Policy (Cambridge, Mass.: The
MIT Press, 2001), pp. 127-39, at p. 129.
2There may be some concern that my talk of ontological categories in this respect
(according to which one such category might be that of “human beings”) is misleading,
given that ontological categories are actually much more general in nature (e.g., catego
ries of fact, property, particular, substance, and so on). On this more general terminology,
“human being” would not constitute an ontological category; rather, it might be some
thing that belongs to a particular ontological category. This is indeed true. What we are
concerned with here is the “what is it?” question, the answer to which will place the par
ticular under a substance category. So “human being” is, we shall assume, one type of
substance category, with built-in specifications both for what that thing is and what its
persistence conditions are across time, and our question will be whether or not fetuses or
embryos fall under that subcategory. See, for example, Eric T. Olson, The Human Ani
mal: Personal Identity Without Psychology (Oxford: Oxford University Press, 1997),
) Copyright 2005 by Social Theory and Practice, Vol. 31, No. 1 (January 2005)
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52 David W. Shoemaker
fetuses, at least resemble clear-cut hum
rather closely, and so granting them th
ings is a rather easy pill for many to s
comes in establishing a coherent and/or
about the fetus’s moral status from there.3
However, the debate over stem cell re
therapeutic cloning, and other forms of
lar in this formal respect to the abortio
ferent regarding the subject of the bro
embryo from which the enormously sig
for example, and it is (for now, anyway
rich potential. Once an embryo has dev
ing potential is lost. So there are differe
the various procedures: abortion is typi
expected utility for the mother/parent
the like are typically desired on the bas
the grandest of schemes, humanity in
offered against both procedures typicall
fact: both abortion and the harvesting
tion of a living human organism. And i
actually a human being, and it is (for w
human beings, then it would be wrong
tion. Now, as I have already noted, lateclear-cut human beings (of the infant v
their status as human beings, which wou
first of our two general questions. But to r
why should we think an embryo is a hum
pp. 28-29. Nevertheless, both for the sake of brev
terminological tradition in the literature on ab
“ontological status” as a gloss on this form of cat
3See, e.g., Don Marquis, “Why Abortion is Im
(1989): 183-202, reprinted in Julie McDonald
Diverse Society (Belmont, Cal.: Wadsworth Pub
lish, “Abortion and the Concept of a Person,” C
233-43; and Judith Jarvis Thomson, “A Defense
fairs 1 (1971): 47-66.
I should make it clear that I am not “fudging
status, nor do I want to attribute such an equivoc
Mary Anne Warren, “On the Moral and Legal St
Joel Feinberg (eds.), The Problem of Abortio
1997), pp. 59-74], at pp. 65-66, for a succinct ar
There are two distinct topics of potential explora
a human being, a member of a particular categor
(b) what is it about members of that category, if
certain moral protections (moral status)? I am e
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Embryos, Souls, and the Fourth Dimension 53
The stem cell issue is primarily a public policy issue, but despite the
fact that this debate is taking place within secular democracies like the
U.S. and the U.K., religious arguments against such research are regu
larly heard and taken into consideration by various public advisory
committees, leaving many secular liberals with their collective jaws
agape.5 But while there are very good reasons why such religion-based
arguments should be rendered weightless as justifications for public pol
icy, I propose instead for now to take them quite seriously, for two rea
sons. First, a large number of citizens accept these religion-based argu
ments about human beings, and their beliefs about the limits of public
funding for certain scientific pursuits flow directly from such arguments.
Failing at least to address these arguments, then, leaves the impression
that the government is silencing a significant portion of its citizenry, and
the undercurrent of resentment produced by such a perceived silencing
may express itself in less peaceful ways in the future (think here of abor
tion clinic bombings). Second, even if the religion-based view is dis
counted at the political level, it still represents a moral stance, one pro
ducing various publicly expressed (if not politically legitimate) judg
ments about Tightness and wrongness that may ultimately be influential
in generating enough public pressure to stop certain scientific pursuits
altogether, despite the absence of any legal constraints.
My aim in this paper, then, is to deal with these arguments head-on.
More specifically, I hope to show that the best developed and most popu
larly cited religion-based argument(s) about the ontological status of em
bryos/fetuses, focusing on the nature of human beings and the beginning
of life, yields, upon close inspection, an overwhelming number of prob
lematic theological and metaphysical implications, many of which have
not been discussed before. But because this is an issue in which the bio
logical details are crucially significant, we must start there.
Biological Basics
We begin, as I suppose we should, at conception. When an ovum is fer
tilized, it is a zygote. Fertilization takes place in the oviduct, and in the
days following fertilization, a number of divisions take place, as what is
now a very early-stage embryo travels down the oviduct into the uterus.
For the first five days of development, the cells (called “blastomeres”)
question in this paper. I certainly recognize that the two questions are often conflated, but
I believe that we can, and that it is important to, deal with them separately here. See also
n. 10 below.
5See, for example, Erik Parens, “On the Ethics and Politics of Embryonic Stem Cell
Research,” in Holland et al. (eds.), The Human Embryonic Stem Cell Debate, pp. 37-50.
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54 David W. Shoemaker
are entirely undifferentiated; that is, at this
act like any particular specialized cells of
them is yet committed to any particular dir
could potentially form any such cell, or eve
fledged infant (a capacity known as “totipo
after fertilization, a significant developmen
at the outer layer separate off from the in
trophectoderm, a kind of protective circle
enables implantation of the embryo into the
ally form part of the placenta. This stage of
ICM and surrounding trophectoderm) is cal
blastocyst is implanted, mediated by the tr
soon differentiate, becoming other cell typ
tential is now much more restricted.6
Stem cells are derived from a pre-implanta
collections, the ICM is separated from the t
are already differentiated), those ICM cells
cells ultimately derived from those ICM cel
which can “proliferate and replace themselv
the developmental potential to form any cell
By now the possible benefits of stem cell
several months of culture, they have the cap
cell of the human body, from blood to nerv
us to have unlimited supplies of specific, tra
treatment of anything from leukemia to Par
establishing stem cell lines requires separat
phectoderm, a procedure that, of course, dis
both are by now constituent parts. Therefor
implantation embryo is already a human be
for culture (which effectively deprives it of
fetus and beyond) kills a human being. Thus
There is one last significant biological con
incredible plasticity of the pre-implantatio
capable of both fission and fusion. If, for e
cells are divided, each half (once implanted)
into its own normal individual fetus. This i
formed. On the other hand, though, if two
6I have borrowed much of this exposition from J
Embryonic Stem Cells,” in ibid., pp. 15-17.
7Ibid., p. 17. This exposition should make clear, the
the cells of the embryo itself; they are rather cells ult
ICM) of a pre-implantation embryo.
8Ibid„ p. 15.
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Embryos, Souls, and the Fourth Dimension 55
embryos are pushed back together (or fuse naturally), they can intermin
gle to form a single embryo that may be brought to term as a single, indi
vidual infant. In addition, it is theoretically possible to fuse together two
early-stage embryos, each composed of cells of different genotypes, to
produce a single infant with four parents.9 This remarkable possibility
will be important for the arguments to come.
We may now turn to the more philosophical issues at stake. Specifi
cally, we have before us the crucial question of ontology: is the pre
implantation blastocyst-stage embryo a human being? I begin with an
exposition of a very familiar reply.
Religion and Public Justifications
The most popular contemporary immaterialist answer to this question,
based on the stated view of the Roman Catholic Church, is as follows:
the embryo is indeed a human being, and what makes it so is that it has
an immortal soul, a soul implanted by God into the physical organism
from the moment of conception. In doing this, God not only renders the
developing life form a human being, but also simultaneously renders it
deserving of moral protection. In ensouling the conceptus, God not only
makes it a creature with a certain ontological status (human being), but
also instantly establishes its moral status, as a being with dignity, etc.10
The following passage from the Instruction on Respect for Human Life in
its Origin and on the Dignity of Procreation: Replies to Certain Ques
tions of the Day, authored by the Congregation for the Doctrine of the
Faith in 1987, makes this view explicit:
From the moment of conception, the life of every human being is to be respected in an
absolute way because man is the only creature on earth that God has “wished for himself’
and the spiritual soul of each man is “immediately created” by God; his whole being
bears the image of the Creator. Human life is sacred because from its beginning it in
volves “the creative action of God” and it remains forever in a special relationship with
9Ibid., p. 16.
10Once again, this distinction is important. The soul, according to most theological
views, serves two functions. First, because it is thought to be immortal, it serves to mark
a fundamental ontological distinction between human beings and non-human creatures:
only humans are immortal, and the soul is the vehicle for preserving identity between
flesh-and-blood humans and their heavenly (or hellishly!) successors. In virtue of this
function, it confers a special ontological status. But the soul also serves to confer moral
status: it constitutes the source of dignity in a human being. So while one allegedly gets
both ontological and moral status simultaneously, neither status is received in virtue of
the other, i.e., one does not get moral status because one has a certain ontological status,
or vice versa. In either case, one gets the particular status one has in virtue of one’s soul.
In what follows, however, I will focus solely on the function of conferring ontological
status served by the soul.
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56 David W. Shoemaker
the Creator, who is its sole end. God alone is the
end: no one can, in any circumstance, claim for
innocent human being.”
What, though, is meant by “soul”? One
what Descartes meant, viz., a thinking
view that embryos have souls also holds
to have a soul, on this view, requires no
ties. Nevertheless, given the host of r
must eventually have both to God and
and given the (dogma-based) need to d
non-human animals via reference to sou
rationality must somehow play a role in
And so it does. Current Catholic theolo
dividual substance of a rational nature.”1
There are four aspects worth noting in
part first, souls have a rational nature, so w
think, that aspect may not be active, or ye
of their existence. To take a rough anal
clock to tell time—clocks have a time-te
installed in it, say, that part of the clo
Similarly, it is a functioning brain that
pacities on earth; nevertheless, even w
tional nature. Second, the soul is a subs
it is an enduring entity, a continuant t
and change. Third, the soul is an immat
thing. It is thus something for which t
pirical evidence. Fourth, the soul is an in
one thing. Given that it is unextended,
stance, then,14 having neither extension
supports the theological view that the
ruptible.15 It is the possession of this i
“introduction, Section 5, published by the Cat
on the web at
ment of The Third Plenary Assembly of the Pon
City, 14-16 February 1997, at http://www.vatica
l2Michael J. Coughlan, The Vatican, the Law
University of Iowa Press, 1990), p. 59.
13Thomas Shannon and Allan B. Woltor, “Reflec
Embryo,” Theological Studies 51 (1990): 603-26,
14See, e.g., Roderick M. Chisholm, “On the Si
Perspectives, vol. 5, Philosophy of Religion (199
l5Coughlan, The Vatican, the Law and the Huma
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Embryos, Souls, and the Fourth Dimension 57
physical) thing, therefore, that renders an organism a human being, and if
God creates it immediately to be possessed by a newly created concep
tas, then that developing organism is a human being at every stage from
there on out.
There are many questions we might ask here. For instance, how could
we possibly know if an embryo were to have a soul? If souls were truly
immaterial, then determining this would be impossible. Given this prob
lem, what possible non-arbitrary reason could there be for marking con
ception as the spot where ensoulment occurs, as opposed to any other
stage of the developmental timetable? Indeed, throughout history various
theologians and religious philosophers have pointed to different stages as
the points of ensoulment. Aquinas, for instance, following Aristotle,
claimed that male fetuses received souls about forty days after concep
tion, while female fetuses received souls about eighty days after concep
tion, presumably because these were the days when fetal movement was
typically first detected (although one might harbor some suspicions about
the statistical methodology at work here). And other candidates for the
stage of ensoulment have included viability, brain activity, and the point
at which the primitive streak has developed.16 But each chosen stage is
just as suitable a candidate as all the others, insofar as we could have no
evidence whatsoever to believe that one is more likely than the others.
Because of our complete lack of evidence in these matters, it might be
thought, we have no reason to accept the claim that embryos have souls.
This is an epistemological argument, however, that may simply have
no bearing on the actual metaphysical facts of the matter. For it still
seems logically possible, at any rate, that embryos do have souls, regard
less of the fact that we could never know that. If so, then if the having of
a soul renders its bearer a human being, embryos might, for all we know,
be human beings, in which case a “better safe than sorry” argument
could be offered to extend some moral protection to them.
To avoid this line of attack, therefore, many people in favor of stem
cell research have offered a general and purely political argument against
16There have also been divisions into types of souls received at various stages. Aqui
nas, for instance, following Aristotle, distinguished between vegetative, animal, and ra
tional souls, and this division also represented the ordered sequence in which these souls
were “received” by developing humans. For a fascinating brief history of the Catholic
Church’s evolving position on embryos, fetuses, and souls, see H. Tristram Engelhardt,
Jr., “The Ontology of Abortion,” Ethics 84 (1974): 217-34, esp. pp. 226-27.
l?From the Los Angeles Times, 24 March 2002, a letter to the editor (by James Bjor
seth): “Even the wisest among us must acknowledge that they are not qualified to answer
the question of when life begins … If we can’t be sure then we must err on the side of
caution and not terminate any existence.” I have no doubts whatsoever that this writer
means to include only human life under this principle, though. Cockroaches should still
beware. See also Coughlan, The Vatican, the Law and the Human Embryo, chap. 6.
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58 David W. Shoemaker
the use of the soul argument in matters of public policy. It is a familiar
one, and it goes as follows. If one’s support for the claim that embryos
are human beings is that they have souls, then this sort of argument is
simply illegitimate in a secular democracy, even if it turns out ultimately
to be true. When offering a public justification for some policy or other,
one’s arguments must appeal to reasons that respect the equality of all
citizens. Arguments having their sole source in a specific and quite con
troversial religious view fail to do so, however, insofar as they appeal to
premises utterly unacceptable to citizens of other religions, or to citizens
who reject religion altogether. A public policy adopted on the basis of
such religious justifications, then, would involve state promotion of one
religious view over other religious and non-religious views, rendering the
citizens who advocate these alternatives without a voice, unequal with
respect to this policy. This is not to say that a viable public justification
for religious folks who want to protect embryos cannot be found; it is
rather to say that any premises on which they build such a public argu
ment would have to be ones that respect the equality of all citizens. What
would need to be found, then, is some basis for the conclusion that is
shared by all reasonable citizens.19
While I believe this to be a knockdown argument against the religion
based justification with respect to public policy, it will be, as already
noted, terribly unsatisfactory for practical reasons to an advocate of the
view, and it also does nothing to undermine the moral argument itself.
The soul argument is repeatedly and cursorily dismissed in the philoso
phical literature,20 but I nevertheless believe it to be worthwhile to take
the argument quite seriously, in part for the practical and moral reasons
already cited, but also because of its extremely interesting implications
for other important issues in the philosophy of religion and metaphysics
18See, for one example, Parens, “On the Ethics and Politics of Embryonic Stem Cell
Research,” pp. 40-41. For an alternative perspective, see Françoise Baylis, “Human Em
bryonic Stem Cell Research: Comments on the NBAC Report,” in Holland et al. (eds.),
The Human Embryonic Stem Cell Debate, pp. 51-60.
I9I am obviously drawing here from the sorts of arguments with respect to the
grounds of public reason in a liberal democracy put forward by John Rawls, in Political
Liberalism (New York: Columbia University Press, 1993), esp. Lecture VI: “The Idea of
Public Reason.”
20See, e.g., Engelhardt, “The Ontology of Abortion,” p. 227; Lawrence C. Becker,
“Human Being: The Boundaries of the Concept,” Philosophy & Public Affairs 4 (1975):
334-59, p. 340 fn. 2; and Paul Bassen, “Present Sakes and Future Prospects: The Status of
Early Abortion,” Philosophy & Public Affairs 11 (1982): 314-37, pp. 326-27. Two excep
tions, however, are Coughlan, The Vatican, the Law and the Human Embryo, chap. 5, and
Ronald M. Green, The Human Embryo Research Debates: Bioethics in the Vortex of
Controversy (Oxford: Oxford University Press, 2001), pp. 31-32. While my approach in
the early stages of my argument will be similar to these two, I eventually go far beyond
them to discuss a number of other troublesome implications for the theological view.
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Embryos, Souls, and the Fourth Dimension 59
generally. I believe we will find that the view ultimately is either absurd
or commits its advocates to some very troubling implications.21
Was I an Embryo?
I doubt I will cause any theological controversy by suggesting first that
souls are intended to provide fairly significant unity relations. Specifi
cally, an ensouled entity is unified both synchronically and diachroni
cally by its soul. At any given time, for instance, what unifies the various
physical parts of a material ensouled entity is its immaterial soul. What
makes its collection of parts one unified thing is that there is an indivisi
ble individual soul attached to it. In addition, this single soul is what pro
vides unity across time (given its status as a substance). Insofar as it
would be the essence of a human being, X at time tl would be identical
to Y at time t2 (assuming X and Y were both ensouled human beings) if,
and only if, Y’s soul were numerically identical to X’s soul. This latter
feature is crucial to the eschatological requirements of the theological
view: the unity of my soul across time enables me to survive the death of
my body in heaven (or hell). Someone in heaven will be me just in case
that person is—or has—the same soul I was—or had—on earth.22
On this overall view, then, a human being is an entity deeply unified
both at a time and over time by his or her soul. So if a pre-implantation
embryo were a human being in virtue of having a soul, this fact would
have two implications. First, the various cells of the embryo would be
21I should point out before beginning that some of the arguments I will advance are
formally similar to those from familiar philosophical literature on abortion and embry
onic research. Helga Kuhse and Peter Singer, for example, have offered arguments for the
absurdity of claiming that a conceptus is a human being by drawing on the identity con
siderations involved in fission that I marshal below (see, e.g., ‘The Moral Status of the
Embryo,” and “Individuals, Humans, and Persons: The Issue of Moral Status,” in Peter
Singer, Unsanctifying Human Life, ed. Helga Kuhse (Oxford: Blackwell Publishers,
2002), chaps. 12 and 13). Nevertheless, Kuhse and Singer (and others) typically start with
materialist assumptions, and so their arguments are easily sidestepped by someone start
ing with immaterialist assumptions about souls, so I will be adapting the argumentative
methodology they have employed specifically to this religion-based position, which will
require several additional sorts of arguments from those seen before (with some excep
tions; see n. 20). In addition, the conclusions I will draw are very different from those
Kuhse and Singer draw.
22It remains a wide-open question, though, just how these unity relations are pro
vided, i.e., how an immaterial substance could possibly unify a material particular. I can
not begin to articulate a theological response to this version of the mind/body problem, so
let us simply allow that it somehow does so and, to paraphrase Samuel Johnson, “there’s
an end on’t” (James Boswell, The Life of Samuel Johnson (1791), quoted in Gary Wat
son, “Introduction,” in Gary Watson (ed.), Free Will (Oxford: Oxford University Press,
2003), p. 1).
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60 David W. Shoemaker
unified as one individual entity—a human
that synchronically unified individual ent
tical to all the later stages of the fully dev
ther standard assumption that a spatio-
houses the same soul throughout its lifetim
souls do not “jump” from one body to anot
fore, I now am identical to—I am the same
ized egg from which I developed many yea
same essential substance underlies and unif
seems, an embryo.24
To evaluate this view, we may begin w
identity. Ordinarily, when applied to talk
question of synchronic identity is about th
ous mental states; that is, what unifies var
perceptions at time t as being those of one
embryo has no mental states. The issue of
only be a question, then, about its various
cate of the soul view answers that some co
human being at t in virtue of its having a s
the matter implies that there is another (an
play here, however. After all, to identify
cannot point to a soul; instead, we must po
cal cells that together are inferred to consti
then what is it about those cells that privi
part of the unified, ensouled entity? The an
what makes them a distinct ontological obj
souled. Instead, they must already constitut
or becomes ensouled. What the soul alleged
cells into one human being, but the cells tog
a distinct ontological object in order then
distinct ontological object in virtue of thei
were not the case, we would have no means
ject under discussion. Thus, the relevant, id
the cells constitute is that of a human embr
according to the theological advocate, that i
not just an embryo but also a human being.
23I will distinguish and discuss two importantly dif
the nature of this relationship below.
24And of course that embryo would also have confe
ensoulment the appropriate moral status.
25At the end of the paper I will actually entertain
human beings (independent from their collection of m
save the soul view, but I will nevertheless reject that v
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Embryos, Souls, and the Fourth Dimension 61
But if this is the case, then what precisely is the metaphysical relation
between embryos and human beings? More specifically, with respect to
the question of synchronic identity, what is the relation between what
unifies the cells at t qua embryo and what unifies them at t qua human
being? Consider, for example, what happens at around five days after
fertilization, when certain cells separate off from the ICM to form the
trophectoderm. The entire collection, including the outer layer, still falls
under the rubric of “embryo” (or, more precisely, the stage of the embryo
called a blastocyst). But it is only the cells of the ICM whose descen
dants will form a fetus and then an infant. Are the cells of the trophecto
derm, which are synchronically unified with the cells of the ICM at this
time as an embryo, also unified as part of a single human being via the
soul? If so, then the shedding of the placenta as afterbirth (and its even
tual casual destraction) would seem to have heretofore unrecognized
moral implications, insofar as it would involve the destruction of at least
part of a human being. Surely this cannot be right, though, and as far as I
know, no one holds that the placenta is part of a human being. If not,
then the ontological object to be ensouled is not the embryo but the ICM.
But the ICM does not come into existence until around five days post
conception, which might introduce a wedge against the soul theorist who
wants to maintain that human beings (via souls) come into existence at
conception. And this could be all the wedge the stem cell theorist needs:
if stem cells could be derived from the cell mass prior to the formation of
the trophectoderm, then no human beings would be destroyed in the
process, and thus there would be no such soul-based objections to doing
One response on the soul theorist’s behalf, though, might be that the
identity of the human being does not necessarily track any specific, uni
fied, material ontological objects across time. So while the ensouled ob
ject at any given time (synchronic identity) will correspond to some iden
tifiable material ontological object, the object to which it corresponds at
some other time may be different. Thus while the ensouled human being
is a zygote on the first day, it may be merely an ICM on the fifth day
(and not the entire embryo). Clearly the ICM is a direct descendant of the
zygote, though, and while our typical conceptual categorization includes
the trophectoderm as part of the embryo, it is only part of that embryo
that is significant for fixing the referent of “human beings.”26
This response shifts the focus from synchronic identity to diachronic
identity, rendering the former derivative from the latter, at least with re
spect to identification. In other words, identification of the relevant mate
26I will discuss a powerful objection to this move at the very end of the paper, but for
now I will allow it to explore its many important implications.
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62 David W. Shoemaker
rial ontological object at a time will dep
the relevant material ontological object
ings may not correspond precisely to em
we fix the appropriate unity relation acr
vant material ontological object being
able to fix what material ontological ob
particular time, for it will be whatever s
object that is appropriately related to its
Let us turn, then, to considerations o
first the familiar problem of twinning.
ICM cells are still undifferentiated, s
sionally does) divide into two or mor
then develops into its own individual fe
from the two-cell stage to approximatel
What is the status of the soul in this case?
The possibility of twinning has been much discussed in the literature
(albeit rarely with respect to souls), and it poses a genuine threat to the
coherence of the theological view on which we are focusing.27 The rea
son I am going to discuss it yet again is actually twofold. First, to be as
sympathetic to the soul view as possible, I need to spell out all the crucial
details of this objection to it so I can explore in equal detail possible re
buttals from the theological camp. There are a variety of ways the soul
theorist might handle this possibility, yet these ways are simply not dis
cussed by writers who advance the twinning scenario.28 Second, the
problem of twinning raises a very important issue regarding the general
ontological picture of the soul theorist. Specifically, I believe this theorist
(under one specific conception of souls) cannot maintain a coherent view
of the persistence conditions for his ensouled human beings—that is, to
the question, “Do human beings endure or perdure?” this theorist has no
coherent answer. Consequently, I beg indulgence from some readers for
whom this initial discussion may seem like a reheated rehashing. There
are larger issues afoot, but it will take a bit of time to set them up.
Onward to the possibility of twinning, then. If, as already noted, the
soul is a simple substance, then it cannot divide along with the dividing
27For just two examples in which souls and twinning have explicitly been discussed,
see Coughlan, The Vatican, the Law and the Human Embryo, pp. 71-74, and Green, The
Human Embryo Research Debates, pp. 31-32. For discussions of twinning used to un
dermine the materialist (non-soul-based) view that human beings come into existence at
conception, see Kuhse and Singer, “Individuals, Humans, and Persons,” esp. pp. 189-92.
28See, for example, Coughlan (The Vatican, the Law and the Human Embryo), whose
otherwise careful and balanced discussion of the Church and its position on the human
embryo is too abrupt and one-sided when it comes to his discussion of souls and em
bryos. On pp. 72-73, he asks a number of seemingly devastating questions to the soul
theorist that he makes no effort to answer on their behalf. I attempt to do so below.
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Embryos, Souls, and the Fourth Dimension 63
cells. If the pre-fission cells are ensouled, therefore, what happens to that
human being—call it Adam—during fission? There are four possibilities:
(1) Adam survives as both fission products—that is, Adam’s soul is em
bodied in both of the survivors; (2) Adam ceases to exist altogether (here
on earth, anyway), and the two fission products are two new human be
ings, each with their own new souls; (3) Adam survives as one of the
fission products, while the other at that point becomes a newly ensouled
human being; (4) Adam is actually two human beings, with two souls,
until fission, at which point one soul serves to unify one clump of cells,
and the other soul serves to unify the other clump of cells. Nevertheless,
there are problems with all four possibilities.
We can rule out (1) right away. If developed to term, the fission prod
ucts would eventuate in two spatio-temporally distinct entities, capable
of living on opposite sides of the earth, undergoing radically different
experiences, and perhaps even fighting each other. Nevertheless, on this
possibility, they would together still constitute only one human being
(because only one soul). But this would wreak havoc with our ordinary
conception of human beings. If one kills another, would it then be a sui
cide? If, through a bizarrely incestuous turn of events, they have sex with
one another, is it merely masturbation? And so on. Clearly, the two fis
sion products would eventually have to be two human beings, and thus, if
the formula is one soul per human being, two souls.
What of (2)? On this possibility, Adam is destroyed (put out of com
mission on earth) by fission, making way for two new souls to pop into
existence, each corresponding to one fission product. At the very least,
this possibility raises a new angle on the problem of evil: since God
regularly allows such divisions to take place, he is regularly allowing the
pointless (earthly) deaths of numerous human beings. Indeed, this possi
bility raises an even worse scenario: not only is God allowing these
pointless deaths, but because he would be responsible for ensouling the
doomed-to-fission cells in the first place, he would also be responsible
for causing them to die as human beings. Surely, if he were omniscient,
he would have known that the cells would divide. Why ensoul them pre
fission, then, if failing to do so would prevent the needless deaths of such
human beings? Indeed, why should the creation of two new human be
ings come only at the expense of the life of one human being? On its
face, there seems to be no available theodicy that could plausibly account
for this possibility’s particular brand of senseless evil.
To avoid such worries altogether, though, it might be the case that
God waits to ensoul potential splitters until after fission occurs, given
that he would know when this would take place. But this alternative
would leave some embryos, namely those “predestined” for fission, soul
less, and thus not human beings, which once again would violate the
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64 David W. Shoemaker
theological assumption we are working w
beings begins at conception. If we allow
(qua human beings) would only begin pos
possibility would presumably make harv
for-fission embryos (assuming we could
destined) perfectly permissible, if the o
such procedures were the ontological sta
the embryo here would be more akin
Nevertheless, because the destruction of
lives of two human beings would be prev
as opposed to only one in the case of a n
cause many Catholic theologians also fin
precisely this sort of reason), there may
Nevertheless, because this possibility wou
position on the ontological status of the
man being, it should be set aside.
Next consider (3), according to whic
fission product, while a new soul pops in
the other fission product. Once again, th
not all human beings come into existen
human beings come into existence only
since the presumption is that one soul (h
moment of conception, we have a puzzle
be Adam, and which would have the new
no non-arbitrary reason God could have
given that each would be exactly similar
not too brittle a bullet for the theologian
able that God occasionally acts entirely o
coin-flip. More on this point in a moment
Finally, consider alternative (4), accor
souls present all along from conception,
soul now becomes attached to the separa
allows the theological advocate what he s
the lives of all human beings begin at con
cost. For one thing, it implies that tw
“body” (prior to the fission), but this po
one soul assumption. Perhaps, though, be
only be temporary (and God would know
would ensue.29 Not so fast, though, for
explored idea of fusion. As mentioned ea
could be pushed back together to form a
29I will explore precisely this issue in detail in th
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Embryos, Souls, and the Fourth Dimension 65
will, if implanted, develop normally into a single infant. What would
happen to the two fissioned souls if we were to do so in this case? If
souls are simple, individuated substances, then presumably they could
not fuse together to form a single individual. So the only possibilities are
that (a) both souls would remain housed in the fused embryo; (b) both
would be replaced in the fused embryo by a new soul; or (c) only one of
the two souls would live on in the fused embryo. Possibility (a) cannot be
true, for it would again imply that two (or more!) human beings could
exist simultaneously in one body, and the “temporariness” escape clause
above would no longer be met, given that the infant would continue to
develop its individual body into adulthood and beyond. A view implying
that one adult body contained two wholly distinct and individual human
beings would be absurd. Possibility (b) is problematic for two reasons.
First, it seems an incredible waste: why would God remove both souls
(allowing two human beings to die on earth) when one could (easily?) be
transferred to the fused embryo? Second, this possibility would again
mean that the new embryo would be a new human being, a human being
coming into existence sometime post-conception, an implication that vio
lates the general theological assumption under which we are working.30
So (c) would have to be the safest theological bet: one soul would be re
moved, while the other would remain and be attached to the new fused
But there are a few problems with this proposal as well, depending on
one’s conception of the soul. There are, in fact, two importantly different
conceptions of the soul that the Church has worked with over the years,
conceptions that remain (in some quarters) competitors to this day. On
the one hand, there is the Thomistic version of the soul, a conception de
rived in part from Aristotle. On the other hand, there is the Augustinian
version of the soul, a conception derived in part from Plato. According to
the Thomistic view, the soul is by nature embodied-, it is a formal design
that has no real existence unless it is instantiated in a particular body,
much like a coin, whose essence consists in both its formal design
(shared by all such coins) and its particular physical construction.” This
is a hylomorphic view of souls, and Aquinas argued that it is only this
conception of the soul that can make sense of the Christian doctrine of
the resurrection of the body in the afterlife, for without a body there
could be no particularized person.32 According to the Augustinian view,
which is a dualistic conception of the soul, the soul can exist independ
ently of the body, and it is only temporarily (on earth) housed—some
30Thcre is also a third problem, having to do with what kind of deaths would have
taken place here, a problem I discuss below.
31 See Coughlan, The Vatican, the Law and the Human Embryo, p. 18.
32Ibid„ p. 19.
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66 David W. Shoemaker
might say trapped—in a body. Salvati
the boundaries of the body, which prod
overcome.33 On this view, the immort
terial—exists without a body in the afte
The Thomistic view is presented as Ch
the Augustinian view remains popular
as much of the public (perhaps due to
cartes). Up to this point, it has not bee
but what I wish to argue now is that n
soul is maintained, there will be seri
metaphysical implications in light of th
Return, then, to possibilities (b) and (c
maintains the hylomorphic conception o
one’s theology belief in the resurrection
ensouled human beings that existed prio
disappears; in possibility (b), two disapp
human tissue died (or disappeared) at al
where are their bodies? This certainly
rection of the body, if there are no ex
The “life begins at conception” theolog
sion of the soul seems to be committed
sitions: (l)each “body” prior to fusio
fuse together; (3) there can only be a
bodies and souls; and (4) there is a re
person’s bodies) in the afterlife. But
tions in the fusion case, then this theo
contradiction: option (a) contradicts pr
(c) contradict proposition (4). Which
vates the claim that (a)-(c) are the only
theologian gives this up (which seems t
must also give up the claim that the lif
conception, however, and this would pr
theorist with a significant wedge agains
On the other hand, perhaps this th
Thomism altogether, specifically propo
the Augustinian conception of the soul
and (c) may not seem so problematic. A
of bodies, they can certainly survive wi
remove a soul from certain groupings o
that that soul (and any rational being it
“ibid., p. 17.
34Cf. ibid., p. 72.
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Embryos, Souls, and the Fourth Dimension 67
in the afterlife. Now again, option (b) seems quite strange (God would be
removing both souls when he could have just transferred one of them to
the fused embryo), and it again denies that the life of all human beings
begins at conception. So consider again the best option for the Augustin
ian, option (c), according to which God does indeed remove one soul and
transfer the other to the fused embryo.
The first question to ask is which would be which? Each of the origi
nal embryos would have the same full-fledged human status, and each
would seem an equally legitimate candidate for having its soul trans
ferred to the fused entity. Once more we have a situation similar to the
third alternative in the fission case: here too there simply would be no
non-arbitrary reason for saying the survivor is identical to one of the pre
fusion humans rather than the other. Keep in mind that the thing God
would have “attached” to it—the soul—would at this point itself have to
be utterly featureless. No one who holds that embryos are ensouled hu
man beings maintains that there is any thinking going on at that early
stage; the rational capacities of the soul would not yet have been acti
vated. But if the soul is immaterial, and it does not yet have a psychol
ogy, then there would seem to be nothing in virtue of which it would—at
this point, anyway—be distinguishable from other such souls. It would
be a completely featureless “nugget,” somehow constituting the essence
of particular human beings, without itself yet being particularized in any
way. Thus, there could in principle be no reason for God to assign the
fused organism one soul over the other, based on their present properties.
They would at this point be entirely interchangeable, entirely indistin
guishable, and so there could be no basis at all on which to assign one of
the pre-fusion souls into the fused organism. Indeed, this is precisely
why Aristotle (and Aquinas) objected to the Platonic conception of souls
in the first place.35
There are two seriously problematic implications of the view, then.
For one thing, if embryonic souls are featureless nuggets, then it is ex
tremely difficult to believe that they could have any moral status whatso
ever. What possible reason could there be to assign moral protection to
an entity devoid at that time of any particularized features, with neither
individuated material form nor any psychological characteristics? The
350ne might maintain, however, that, perhaps in virtue of having been attached to an
embryo with a particular complement of DNA for a bit, these souls might not be entirely
indistinguishable after all. (I am grateful to an anonymous reviewer for providing this
possibility.) What matters for my purposes, however, are the intrinsic properties of the
souls in question, and while the history of the soul’s attachments may constitute certain
distinguishing extrinsic properties, there remains nothing about the souls in and of them
selves at this stage that could render them distinguishable from one another. Furthermore,
purely extrinsic properties like these could not possibly help establish the kind of moral
status that I go on to discuss next.
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68 David W. Shoemaker
least problematic alternatives in the fis
God assigning souls to various collection
whim, but this would actually be comple
determining moral status. An updated v
should incline us towards accepting in
because they already have moral status
bryos have moral status because God en
case, then we would need to look som
provides embryos with that independent
Second, we should also not forget t
bryos—numbering millions (or even bil
taneously aborted post-implantation, of
aware of her pregnancy. On the version
sion, we would have to maintain that
mostly undetected and/or ignored, const
tion of human beings of massive propor
“tiniest of human beings” were immorta
exactly would be the point? They again
tinguishable, neither missed nor mourne
them simply “floating” around, capab
tantly, entirely without a personal ident
too pointlessly crowded to contemplate.3
The soul theorist should thus abandon
puzzles of fission and fusion by allowin
stall souls in an arbitrary way. If the em
are thus two options: either there we
along, or there were none until the twinni
can be no objection to stem cell (and o
based on the objection that it destroys
tion is the otily way to go. I have discus
but now it is time to explore it in depth
ing ontological picture required by the s
ultimate downfall.
36Cf. L. Nathan Oaklander, “Personal Identity
(2001): 185-94.
370ne might object to this characterization by
are united to a body in an afterlife (and in that
tity), or (b) perhaps they acquire some sort of ps
ently of embodiment. Option (a) would be a Thom
gustinian reply. In either case, though, the worr
point be simply creating souls intended to exist a
again, what could the point possibly be? Of cours
be a point at all, but without one, we are once m
presume that the Church certainly wants to avoid
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Embryos, Souls, and the Fourth Dimension 69
Dimensions and the Future
Consider a “snapshot” of the five-day-old embryo. We don’t yet know
whether or not it will split into two (or more) distinct embryos. Neverthe
less, the soul theorist wants to maintain that this entity is ensouled, that it
is, at this time, a human being. Now while souls don’t exist in any spatial
dimensions, human beings (as distinctly earthly entities) do. The ques
tion we need to consider, then, is how many dimensions do human be
ings take up? There are two rival theories. According to three-dimen
sionalism, human beings are three-dimensional objects, having spatial,
but no temporal, parts, and they are wholly present from moment to mo
ment. Across time, then, human beings are enduring objects. On the
other hand, according to four-dimensionalism, human beings are four
dimensional objects, having not only spatial but also temporal parts, such
that what exists from moment to moment are temporal stages of a space
time worm. Across time, then, human beings are perduring objects.3
If souls are substances (as they clearly are on the Augustinian view
still under discussion), then what is their role in these rival ontologies?
They of course could not have any spatial parts, being immaterial. But if
they are also simple substances, they could not have any temporal parts
either.39 At any particular moment that a soul exists, it must be wholly
38For a lucid discussion of the rival ontologies, along with a compelling set of argu
ments in favor of four-dimensionalism, see Theodore Sider, Four-Dimensionalism: An
Ontology of Persistence and Time (Oxford: Oxford University Press, 2001).
39While it is obvious why a soul could not have any spatial parts, it may be less obvi
ous why a soul could not have any temporal parts. Normally, of course, temporal parts
are thought to exist, if they do at all, in spnrio-temporal objects, which, if true, would
immediately rule out souls (non-spatial objects) as having any temporal parts. Neverthe
less, it seems in principle possible for there to be objects having no spatial location that
still have temporal parts (see, e.g., ibid., p. 59). What exactly would this mean, though?
The soul would have to have parts that exist only instantaneously (or perhaps over a more
extended interval of instants) and be such that each one of those parts nevertheless wholly
overlaps with everything that is a part of the soul at that instant (or interval). Now insofar
as the soul is supposed to be a simple substance, it is also not supposed to be divisible at
all, either into spatial parts or temporal parts like this. But why not? The restriction
against spatial parts is obviously required by the soul’s immaterial nature. The restriction
against temporal parts would have to follow, I believe, from two aspects of the temporal
parts view that are problematic for immaterial substances. First, the notion of what it
means for a temporal part to “overlap” at t with everything that is part of the soul at t is
an idea of which it is exceedingly difficult to make sense with respect to immaterial sub
stances. This is no problem, of course, with respect to material objects: for a temporal
part of my mug to overlap at t with every part of the spacetime worm of my mug that
exists at t, it just has to be the case that every particle of physical stuff making up the
temporal part of the mug at t takes up the same space as everything that is part of the
spacetime worm-mug at t. But if an object, like the soul, takes up no space to begin with,
it is difficult to see how to specify what it would mean for its temporal part to overlap
with anything. Second, if a soul were to have temporal parts, there would need to be a
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70 David W. Shoemaker
present (in whatever sense we can m
souls). Souls must, then, endure acros
location). And if souls are what make
being, human beings must also, then
dimensional objects.
The problem, though, is that the only
ings-on in the fission and fusion
dimensional ontology of human being
again, this time talking only about hum
intuitive sense. Recall the options: (1)
products; (2) Adam ceases to exist, and
human beings; (3) Adam survives as on
the other is a brand new human being);
human beings who branched off with se
just in terms of our ordinary concept of
simply because one does not equal two
believe, for a variety of reasons; for
ceased to exist when no tissue whats
should the double success of there now b
to Adam count somehow as a failure, as
(3) raises the arbitrariness issue: since b
similar in every respect to Adam, what
be to mark one product as Adam and the
What of Option (4), though? It origina
souls in one body, but removing talk of
ders this option no longer problematic,
view of human beings. If human beings
worms, then they have temporal parts,
involved would be akin to roads that sh
they would coincide for a brief tempor
tinct) before twinning, at which point t
off. For the four-dimensionalist, there
ing, distinct objects at a time. The coin
ject are identical, but that does not ren
cal. Think here of the famous lump/stat
lump of clay on a Monday and creates a
unifying principle connecting the various parts a
again difficult to imagine what that unifying pr
selves—might consist in, if there were no materi
tuting them. For these reasons (and there may w
the “indivisibility” constraint on souls as meaning
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Embryos, Souls, and the Fourth Dimension 71
day (without, of course, destroying the lump in the process).40 If the
statue and the lump are distinct objects, what is involved in the identity
conditions of each? They certainly share all their physical properties in
common, but they don’t share the same historical properties: the lump
has the property “exists on Monday,” while the statue does not. Accord
ing to Leibniz’s Law, they cannot be identical to one another. But how
can two exactly similar things, located in the same portion of spacetime,
both exist? The four-dimensionalist answers that on Tuesday it is only a
temporary part of each object that exists, that is wholly present. These
temporary parts are indeed identical—that’s how they can both “fit” into
this single location—but that does not at all mean that the two objects—
the lump and the statue—are identical with one another, for the lump’s
spacetime worm contains parts (on Monday, e.g.) not contained in the
statue’s spacetime worm.
For the three-dimensionalist, though, there is a huge problem in ex
plaining such events. How can two ontological objects completely over
lap with one another, both being wholly present in the exact same spatial
location at the exact same time, while nevertheless remaining distinct?
There simply doesn’t seem room enough for both objects to “fit.” So if
the statue and the lump on Tuesday are wholly present in the exact same
region of spacetime, in virtue of what could they be distinct objects? And
the same problem extends to the question of the human beings in Option
(4) of the twinning case: if there are two human beings wholly present
but occupying the exact same region of spacetime, in virtue of what
could they possibly be two distinct human beings? There doesn’t seem
room enough for both human beings to fit.
It is here that the soul theorist might try to come to the rescue, mark
ing the distinction between the two human beings not in virtue of any
physical properties, but in virtue of their non-physical properties, viz.,
their souls. Now keep in mind that talk of souls rendering some X a hu
man being presupposes the existence, in some identifiable, material sub
stance category, of an X to which the soul is attached. The “X” in this
case is the embryo—or, more technically, the ICM—so for the soul theo
rist’s case to be made (in Option (4)), the ICM must contain two wholly
present human beings. And because souls have no spatial location, there
should be no more worries about how two human beings could “fit” into
the same spatial region at the exact same time. One embryo could house
two distinct souls, rendering it two distinct human beings, both wholly
present at that time. Now this answer is not a possibility for the Thomis
tic conception of souls, given that on that view souls are formal designs
‘”‘See, e.g., Sider, Four-Dimensionalism, pp. 5-6. For his detailed treatment of at
tempted three-dimensionalist accounts of this case, see pp. 154-61.
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72 David W. Shoemaker
particularized in specific human bodies, s
soul per body. Imprinting two coin desig
yields only one actual coin. But we have
conception as incoherent with respect to
conception, on the other hand, might ve
sibility to avoid the worry under consid
formal designs but are independently
cording to this view, then, human beings
pairs of bodies and souls, so that the ord
is distinct from the ordered pair/human
that both human beings occupy precisely
But while this explanation might accoun
of pre-fission human beings, if it nev
dimensionalist account of the bodies inv
cannot explain the diachronic identity in
After all, what is the relation of B1 to th
time just prior to fission, and t2 the time
one body, Bl. But at t2, there are two
“brand new,” to be labeled B2 and B3, or
that they should be labeled B1 and B2? If
ing ordered pair of bodies and souls ({B
identical to either of the tl ordered pairs.
the resulting ordered pairs ({B2, S2}, sa
identical to neither of the original ordere
of introducing the possibility of two sou
solve the fission case by maintaining that
existence at the moment of conception, (b
and be wholly present in one body pre-f
human beings would be the survivors of
what (b) would have to involve (on a co
count of bodies) contradicts both (a) and
A more promising option might then b
view of the bodies involved, such that so
bodies. What is wholly present at tl, then
a wholly present temporal part of two s
dered pairs involved would thus be funct
tinct bodies to distinct souls, that is, {Bl
and B2 are spacetime worm-bodies who
overlap with one another. Articulating th
the most plausible account of what happ
case (both spacetime worm-bodies shar
while also allowing that (a) both bodyconception, and (b) the two post-fission
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Embryos, Souls, and the Fourth Dimension 73
fied with the pre-fission body-stage as part of the same body (while not
being unified with each other).
Nevertheless, while making this move renders the identity of the bod
ies involved utterly unproblematic, it raises a host of questions about the
identity of the human beings involved. For example, do human beings
(ensouled bodies) endure or perdure? On this account, the bodies in
volved perdure, while the souls involved endure, but how are we to make
sense of what happens to the combination of the two? If human beings
are truly ordered pairs of bodies and souls, then what precisely is wholly
present at til There are only (temporal) parts of two bodies wholly pre
sent, but there are two wholly present souls. Set aside for now the prob
lem of fission and consider an embryo at tl that will not twin, though.
Combining bodies and souls under these competing ontologies in this
simple case yields a straightforward dilemma resting on a logically ex
haustive disjunction: human beings either endure or perdure. On the one
hand, if human beings endure, then all of their parts must be wholly pre
sent at any given time. But on this view only the tl temporal part of our
human’s body is present at tl\ its remaining parts have yet to occur. Thus
not all of the human being’s parts are wholly present at tl, so it cannot
endure. On the other hand, if human beings perdure, then what is wholly
present at any given time must be only temporal parts of human beings.
But on this view the soul renders the embryo housing it a human being,
and because the soul is a simple substance it can have no parts whatso
ever, including temporal parts, so at tl what is wholly present is not just
the temporal part of the embryo/body but the entire soul. Since the entire
soul, and not merely a temporal part of it, is wholly present at tl, the hu
man being involved cannot perdure. Ultimately, then, the view implies
that human beings neither endure nor perdure. But if these are logically
exhaustive possibilities, then the soul view (in this version) is incoherent.
Perhaps, then, as a last resort, the Augustinian soul theorist could
simply abandon the ordered pair approach altogether and press the more
radical view that the souls involved constitute the entirety of the human
beings involved—that is, the identity of human beings has nothing what
soever to do with the identity of any of the bodies involved. This move
would allow the soul theorist to avoid the incoherence associated with
having competing ontologies for material and immaterial objects, while
still allowing her to take the most plausible option in the twinning case:
she can place two souls in the pre-fission embryo, have them be two
wholly present human beings who endure across time, and then locate
each soul in a different body post-fission. Thus if human beings are
wholly spiritual, immaterial objects, then they are not bound by certain
ontological constraints and identity conditions of the material objects in
which they are housed.
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74 David W. Shoemaker
Unfortunately, this move would under
theorist’s project altogether. If the iden
are wholly divorced from the identit
straints of the bodies that house them—
tion of bodies to souls—then human be
objects in any way. But if that is the c
killed, and it would be pointless to obje
search on the grounds that it involves
mantling a house does not kill its occupa
I need to make explicit both what I have and have not shown here. I have
tried to show that there is no way for either Thomistic or Augustinian
soul theorists to maintain, in the light of fission and fusion cases, that
embryos of the sort used in stem cell research are human beings without
rather crippling implications. Thomistic advocates maintain a logically
impossible position in light of the possibility of fusion, wherein humans
die with no physical remains to be resurrected. On the other hand, Au
gustinian advocates, in offering the least theologically problematic re
sponse to fission, cannot put together a coherent ontological picture ex
plaining the relation between bodies and souls unless they divorce souls
from bodies altogether, which renders their overall moral conclusions
Now there may be some views on the nature of the soul that I have
not considered and that could somehow avoid these difficulties. I readily
concede this point. As I have noted elsewhere, the soul is a “slippery lit
tle sucker,” and its allegedly immaterial nature allows for any number of
possibilities, each equally as plausible (or implausible) as the next.41 All I
4’See my “The Irrelevance/Incoherence of Non-Reductivism About Personal Iden
tity,” Philo 5 (2002): 143-60, p. 147. Or, as my former colleague Ron Mclntyre puts it,
one can always just “make up” some quality of the soul that can do the trick. True
enough. On a brilliant episode of The Simpsons, Bart sells his soul to his friend Milhouse
in exchange for five dollars. Prior to this exchange, Milhouse articulates his own theory
of the nature of the soul by saying that it resides “kind of’ in the chest area, and when
you sneeze that’s your soul trying to escape. “Saying ‘God bless you!’ crams it back in.”
And when you die, it squirms out and flies away. To Bart’s probing questions about what
happens if you die at the bottom of the ocean, or what happens if you die in the middle of
the desert, Milhouse glibly replies that the soul can swim, and it also has wheels so it can
drive to the cemetery. After showing this hilarious episode to my students, I then ask,
“And what makes Milhouse’s theory wrong?” Answer: nothing. It’s just as good a theory
about the soul as anything else, precisely because of the soul’s allegedly immaterial na
ture (so perhaps Milhouse’s claims about its having wheels may need to be jettisoned,
unless they’re special, immaterial wheels, of course).
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Embryos, Souls, and the Fourth Dimension 75
have tried to do is examine what I take to be the best, most worked-out
conceptions and applications of the soul view, derived from Catholic
scholarship. Is this then a straw man? If it is, then the outer layer of straw
must mask concrete inside, for this view has been longstanding and very
difficult to destroy. And while I certainly have not destroyed it myself, I
believe I have revealed enough serious problems attached to it that its
advocates should be very reluctant to present it as a freestanding objec
tion to stem cell (and other early embryonic) research again.
Of course, the problems associated with the soul view with respect to
fission and fusion are what have led many of the more reflective theo
logical advocates to mark the point of ensoulment as occurring after the
potential for twinning and such has ended, generally around the four
teenth day after conception when the “primitive streak” that will become
the spinal cord is formed.42 But this move implies that stem cell research,
where the stem cells are derived from pre-implantation embryos between
one and five days after fertilization, would be perfectly permissible. If
the soul somehow determines/marks moral status, and an embryo is not
ensouled until fourteen days after conception, then prior to that point
there would be no soul, no entity with moral status, that would be de
stroyed via stem cell (and other embryonic) research, and therefore, once
more, no good reason to object to it.43’44
David W. Shoemaker
Department or Philosophy
Bowling Green State University
42See Ernie W.D. Young, “Ethical Issues: A Secular Perspective,” in Holland et al.
(eds.), The Human Embryonic Stem Cell Debate, p. 171.
43Actually, though, this view also falls prey to the objections relating to the feature
less nature of the souls implanted even at this point, for embryos with newly formed
primitive streaks would still have no psychological capacities, which means any souls
attached to them would be absent psychologies, and if they were to be spontaneously
aborted at this point, they would still have no particularized, distinguishing, personal
44For extremely helpful comments and insights on earlier drafts of this paper, I am
grateful to Eric Cave, Sean Foran, Josh Glasgow, Doug Portmore, and two anonymous
referees for Social Theory and Practice. I am also grateful to audience members at the
2002 Mountain Plains Conference and colloquia at California State Universities Bakers
field and Northridge, where I tried out many of these ideas. Finally, I would like to thank
the Office of Research and Sponsored Projects, at California State University, North
ridge, for providing me with reassigned time that reduced my teaching load in 2003 while
I worked on this project.
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