Do human embryos have souls?

Fr. Tadeusz Pacholczyk, Director of Education at The National Catholic Bioethics Center, tells us that it is an open question. While it is always and in every case immoral to directly kill a human zygote or embryo, the moral status of this action is not based upon the certainty that a human zygote is a person or has a soul. The moment of “ensoulment” has been a debate in Catholic theology for a millennium and a half, and even occupied St. Thomas Aquinas (who held that ensoulment occurred at time after conception). Fr. Pacholczyk attempts to maneuver the moral landscape in his essay, arguing from teleological and eschatological standpoints with respect to the human embryo’s development. His main points are:

  • The Church has never definitively stated that zygotes or embryos are persons
  • The Church teaches that a zygote or embryo must be treated as if it were a person from the instance of conception, that is, they are to be treated as inviolable and deserving of unconditional respect
  • The question of the timing of ensoulment is not relevant to the moral status of killing a zygote or embryo
  • As integral beings, zygotes and embryos are structured for maturation into full, flourishing human persons and at every instant are capable of receiving a soul from God
  • Destroying a zygote or embryo interdicts God’s eternal plan for the individual human person
  • It would be a greater evil to destroy a zygote or embryo that is not ensouled than to destroy a zygote or embryo that has been ensouled
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  • Zach

    I saw him speak a few weeks ago – he visited my parish! He’s very impressive.

  • Victor

    So then what does Fr. Pacholczyk mean by “soul”? Also, if he isn’t willing to say that the zygote has a (rational) soul–which is the implication of calling into question whether zygotes or embryos are persons–then how does one account for the substantial identity between the zygote and the “ensouled” person, or is there any such identity? But if there is no identity, why should there be any moral dilemma involved in terminating a pregnancy of a “non-souled” zygote. Speaking personally (as if there were any other way to speak), I’m not too comfortable with what appears to be a rather slippery metaphysical slope that Fr. Pacholczyk points place us upon.

  • Sam Rocha

    very nice post, this issue should be troubled more than it is…

  • Br. Matthew Augustine, OP

    Because the immortal soul is the principle by which that person could come to an eternal destiny with God in heaven, so the one who destroyed the embryo, in this scenario, would preclude that young human from ever receiving an immortal soul (or becoming a person) and making his or her way to God. This would be the gravest of evils, as the stem cell researcher would forcibly derail the entire eternal design of God over that unique and unrepeatable person, via an action that would be, in some sense, worse than murder. The human person, then, even in his or her most incipient form as an embryonic human being, must always be safeguarded in an absolute and unconditional way, and speculation about the timing of personhood cannot alter this fundamental truth.

    This strikes me as more than a little problematic. Why refer to a non-ensouled organism as a “young human”, when it is precisely the soul the specifies us as human? While I know this is a disputed question, it seems obvious that the soul, defined as the principle of actuality in living things, is present from the moment of fertilization; i.e., the moment when you have one metaphysically distinct entity which, given the right conditions, will continue its unique and asymmetrical path toward fully actualizing its incipient potential And how could a researcher derail “the entire eternal design of God over that unique and unrepeatable human person”? Do the actions of researchers somehow exist outside the scope of divine providence and causality?

  • Gerald L. Campbell

    This article lacks metaphysical precision. Without going into detail, I’ll just note three problems with terms that Fr. Pacholczyk uses interchangeably.

    Ensoulment, i.e., when a human soul comes into being (as opposed to a vegetative or animal soul). This refers to a formal principle of being. For this reason, it implies universality.

    Personhood designates universality. It does not have the same meaning as Person.

    The Person is unique (an act of being). It is not the same as the soul. Nor is it to be equated with personhood.

    It is is no contradiction to say that the person exists from the moment of conception and that ensoulment occurs at some later time.

    It may be that the Magisterium has not declared on this matter, but it makes perfect sense in terms of Thomistic metaphysics.

  • Liam

    IIRC, even very conservative theologians have made many if not all of these points clear (I’ve not encountered the last one, but all the others).

  • Gerald L. Campbell

    Bro. Matthew,

    “it seems obvious that the soul, defined as the principle of actuality in living things, is present from the moment of fertilization”

    The soul is the formal principle that makes us to be a human being. Yes. But it is only a formal principle; it is not account for existence.

    Being a human being is not the same as being a unique human being. The soul does not account for this unique existence. Moreover, while the soul makes us to be a human being, it does not make us EXIST as a human being nor does it make us to be a unique human being.

    Only the act of being makes us to exist and to exist uniquely.

    The person is situated in the act of being, not the formal principle that is referred to as the soul.

  • Br. Matthew Augustine, OP


    There are two principles which make us a ‘unique’ human being, which correspond to two difference senses of ‘unique’. One, as you say, is the act of existence which is given by God and constitutes a being in its actuality. The other is matter which is the principle of individuation and makes a being this particular thing and not another. My objection presupposes the former.

  • ben

    The dogma of the immaculate conception suggests that in at least that particular instance that the Soul of our Mother was present in her body from the first moment of her existence.

    However, this revealed truth would not constrain God from acting differently in other cases. Certianly the phenomenon of twinning might suggest that the soul would ben infused after the development of discrete individuals. I suppose it would be possible that even in the instance of twinning , God could bestow a second soul, but this would seem to make the first twin in some sense the parten of the second, and that just doesn’t seem right.

    We could also speculate on the creation of Adam. Adam did not first recieve a vegitative or animal soul, he instead recieved his human soul and his existence simultaneously.

    Of course it would also be possible in the case of embryos (and this would speak to the phenomenon of twinning) for the human souls to undergo some sourt of developmental process of individuating.

    These are all very interesting concepts.

  • Gerald L. Campbell

    Bro. Matthew,

    Yes, there are two. Individuation denotes accidental differences where the person denotes the existential difference. This is the basis for Maritain’s distinction between the individual and the person,

    It seems as though the article really confuses basic principles. I was quite surprised and yet concerned.

  • Br. Matthew Augustine, OP

    Moreover, since a person is an individual substance of a rational nature, any substance animated by a human (rational) soul is a person. Therefore, if I am right that a zygote is animated by a human soul, it would qualify as a person.

  • Br. Matthew Augustine, OP


    I’m not familiar with Maritain’s work in this regard, but would be interested in reading it if you could give me a reference.

  • Gerald L. Campbell

    Bro. Matthew,

    You might want to take a look at his book entitled: Existence and the Existent.

  • Victor

    There’s also an appendix to Maritain’s The Degrees of Knowledge that pertains to subsistence and personhood. He also briefly, but very definitely, refers to subsistence vis-a-vis the person–which I think is perhaps what is being alluded to in the person/personhood distinction–in his The Person and the Common Good. I must confess though that I’ve found Maritain’s description of subsistence somewhat troubling, or at least difficult to reconcile with what Thomas himself actually says about the matter (ST I, qq. 29, 75). This is why I think perhaps Maritain describes subsistence in the P&CG with reference to the “Thomistic Tradition,” as opposed to Thomas himself.

    Wojtyla might also be referenced here, in particular his “Thomistic Personalism,” in Person and Community. Much of what he says there regarding personhood seems to agree what Br. Matthew points out with regard to the rational substantial form–just for what it’s worth.

  • Bob

    Man doesn’t have a soul so why would a lump of tissue have a soul?

  • Policraticus

    Man doesn’t have a soul so why would a lump of tissue have a soul?

    Well, if your first assertion is true, then it would seem that a zygote does not have a soul. The problem would be, of course, establishing the truth of the first assertion.

  • Gerald L. Campbell


    The rational substantial form is not unique except as a unique species. This species is individuated by matter. But, at this level, individuation is not spiritual. Yet, the person is spiritual.

    The uniqueness of the person in St. Thomas flows from the act of being. It seems to me that your reading borders on a kind of formalism, or essentialism.

    Maritain’s views on the person is consistent with principles of Thomistic metaphysics.

  • Victor


    Thanks for your thoughts.

    I’m not quite certain what work the qualification “spiritual” is performing here. I’m also not certain how you read me as saying that a rational substantial form is unique. This or that particular person informed with a rational substantial form is unique, yes, but what kind of ontological status does a non-instantiate substantial rational form have in a Thomistic metaphysic? None that I’m aware of except through extrensic denomination.

    I’m also not certain how the uniqueness of a person qua person flows from the act of being. Everything, persons and non-persons, are incommunicably unique insofar as each possesses its own act of being. This is why Thomas will say time and again that, with respect to esse, nothing can be univocal but only analogous (cf. In I Sent., d. 35, q. 1, a. 4; De ver., q. 2, a. 11; De pot., q. 7, a. 7). Are there intensive degrees of individuality?–you bet! That’s part of Thomas’s reason for limiting the term ‘hypostasis’ to individuals of within the genus of substance, and ‘person’ as signifying the singular in rational substances (ST I, q. 29, a. 1).

    Does uniqueness derive from the act of being?–sure, but this is true for non-persons as well. While emphasizing the centrality of the act of being within Thomas’s existential metaphysics–as emphasis I am all too happy to make–one cannot overlook the equally necessary role performed by form or essence. Esse is not itself a thing (i.e., an esse existentiae) after all (cf. De hebdo., c.2: “ipsum esse nondum est”). For Thomas there is no esse without essentia and no essentia without esse. Again this isn’t to deny the underlying existentialism of Thomas’s metaphysics but to recognize all the more his monumental shifting of Aristotle’s substance ontology to a deeper, existential creation metaphysic–one that preserves substance but grounds it in God’s creative causality.

    Regarding Maritain, I will grant that his views are consistent with a “Thomistic metaphysics,” but whether they are consistent with Thomas himself remains, I think, an open question. Never have I seen Thomas describe subsistence as “the ultimate achievement by which the creative influx seals, within itself, a nature face to face with the whole order of existence so that the existence which it receives is its own existence and its own perfection.” Does that make me formalist?–I hope not! But I also have no interest in abandoning form altogether lest we end up with some kind of postmodern philosophy of the ‘event,’ a la John Caputo.

  • Gerald Augustinus

    Destroying a zygote or embryo interdicts God’s eternal plan for the individual human person
    How does one square this with the fact that something like 1/3 of pregnancies self-terminate early, frequently without anyone noticing ? Was the ‘eternal plan’ the almost-immediate destruction ? Another question in this context for the theologians – people who suffer miscarriages they’re aware of think that they’ll ‘go to heaven’. Do all miscarried zygotes, embryos etc. ‘go to heaven’ ? Is there believed to be a minimum requirement of development, etc ?

  • Charles

    I wish to give short remarks about

    1.the use of spiritual,
    2. the theory of human SUBSTANCES in Thomas
    3. and more to think about, an argument for the creation of the soul in the time of conception.

    1. Every being has a substance, the question of human substance is it’s rationality. Reason is not an easy concept as it covers divers conceptions. However, if in Aristotle we find “nous”, merely intellect. Soul in Aristotle is psuche, but we have material soul and immaterial soul.
    In Thomas the vocabulary is wider, in that way spiritual may have the meaning that is separated from materia, what is not from this “world”.

    Spirit could be use as what doesn’t come from the material world, spirit has a specific name when one with the body, soul. Spirit is also the root of the spiritual faculty intellect and will, once again in Thomas “reason” can be wider that intellect and designed also will.

    2. The interesting theory in Thomas is how a thing can change substance. A human adult before to have a rational soul, spiritual soul, had, in Thomas theory, first a vegetative, and then a sensitive soul. A substance of higher degree has the ability to assume, meaning changing, the substance of a being according of its own nature.
    That correspond to the argument that God wont give the spirit before that the organism is ready to receive it. So before to receive a rational soul, meaning spiritual, this body should have the organs ready to receive it, mainly the brain and the nerves system…

    3. But to go back of to theology, and it’s relationship to anthropology.
    When God creates Adam, He was preparing the materia in order to receive the spirit.
    God was acting by second causes as well as first cause, meaning Himself, in order to make that happens. To be short, I could say God was acting in the materia in order that this materia may receive the spirit. Here dynamic could be translated in Greek by energeia, meaning the act by which the potentiality is actualized in its act, according its nature.

    With a fetus, it’s clear that God does not act as first cause, but He is using second causes, the parents. But there is a development of the body, this growth has for final cause to receive the spirit. I have difficulty to accept that this energeia is only material. That is one of the reason that I am know more for the creation simultaneous of the soul and not progressive.

    An other argument with the progressive creation, is death. I think it’s easier to explain the process of separation of the soul with simultanoues than progressive theory.

    Any way, hope my English was not too terrible to read.

  • Gerald L. Campbell


    Thanks for you thoughtful response. It was quite good. But let me try to clarify where we might disagree.

    Long ago, a professor of classical philosophy pointed out to me a serious challenge regarding the reading of Plato. He noted that Plato and Aristotle are, even today, the two chief archetypes of western philosophy. Aristotle, he said, used a logic of division whereas Plato used a logic of unity. A logic of division rests on definitions, i.e., a glossary (e.g., substance, accidents, etc), and employs a subject/predicate language that is tied to those definitions. On the other hand, a logic of unity is metaphorical and lacks the precise distinctions employed in a logic of division. Use of the term “light” in the Republic, e.g., has metaphysical, moral, political, epistemological, and empirical significance. Aristotle’s method breaks this metaphorical unity into separates each of these dimensions into a separate field of study.

    Yet, and this was his point, those who read Plato today use Aristotle’s logic of division as a framework for their interpretation of his dialogues. There are many reasons for this. But one that is central is that modern languages are based on Aristotelian logic. By default, he said, we use Aristotelian logic to interpret Platonic logic. This acts to distort Plato’s vision.

    Something similar happens with our reading of pre-Socratic philosophy. Burnet, Cornford, and Jaeger all represent different ways of thinking that was prevalent in 19th and early 20th century philosophy. Burnet is influenced by scientism, Cornford had an anthropological interest, and Jaeger focused on the continuity between religion and the rise of philosophy (Paideia). It is from these modern philosophical frameworks that their interpretation of pre-Socratic philosophy draws its inspiration. These philosophical contexts explain the wide-ranging disagreements in their interpretations.

    From this, one could argue that the meaning of a philosopher flows more out of a methodology of interpretation than from the subject-matter under scrutiny.

    I’ve long since concluded from this that it is impossible to mirror-image another philosopher. Even if one were to respond to the general question, “Is Plato Doing Philosophy?”,, e.g., one would have to formulate a priori an answer to the question “What Is Philosophy?”. To answer the later question, presupposes that one already has a philosophy, or is a philosopher in their own right. But, even then, being a philosopher is not the same as being St. Thomas or St. Augustine, or Hegal, or Sartre. Yes, as you say, the analogy of being is alive and well here.

    Thus, I look to philosophers, including St. Thomas, more as a source of inspiration than as a criterion that must be emulated. Even such notable scholars of St. Thomas as Gilson, Maritain, Klubertanz, Bourke, Chenu, Garrigou-Lagrange, and Owens disagree with one another on critical points, including the act of being. Look at what St. Thomas himself did to Plato, Aristotle, and, Augustine. Fr. Robert Henle, S.J. wrote a book on Platonism in St Thomas, but Aquinas’ Platonism doesn’t look anything like Plato. Look at what St. Bonaventure and Ockham did to St. Thomas, not to mention Suarez and Cajeton.

    This squares with Henry Karlson’s post quoting Balthazar. See:

    “The truth of Christian life is like manna: it is not possible to hoard it for it is fresh today and spoiled tomorrow. A truth that is merely handed on, without being thought anew from its very foundations, has lost its vital power. ”

    That being said, let me address some of your points. First, I use the term “spiritual” as a way of distinguishing between the extrinsic determinations that individuate the form and the intrinsic act that makes a being exist in a unique way. Individuation flows from material causation. Among individuating factors, one could include size, shape, weight, the impact of disease, education, language, history, culture, etc. These factors differentiate the form and account for one individual to be distinct from another. Maritain could call this composite the individual. Individual, for him, proceeds from material causes.

    But this does not explain the spiritual existence of the person. There needs to be more. To facilitate this line of reasoning, let me pose a question: Can individuation explain the existence of that which is absolutely unique, i.e., the person of Beethoven, or St. Teresa of Avila? Is the person to be distinguished solely on the basis of material causation and the form that is so differentiated? I don’t believe so. Unique talent precedes material causation. It’s potentiality, it seems to me, has intrinsic origins, i.e., spiritual origins. But where does this uniqueness come from?

    Well, it can’t come from the form for that is, in and of itself, universal. Nor can such uniqueness be explained in terms of material causation. This would violate the principle of contradiction — the spiritual coming from the material. The only thing left is the act of existing itself. This Act brings with it a perfection that is unique to that being. It is here where “Beethoven” has his origins — not in extrinsic factors. Thus the being of Beethoven has spiritual origins.

    “Does uniqueness derive from the act of being? –- sure, but this is true for non-persons as well.”

    I agree. But that which is unique is not the same as uniqueness. Uniqueness used in this way is a concept. What uniqueness signifies with non-human beings refers more to difference than to that which is absolutely unique, I believe.

    “one cannot overlook the equally necessary role performed by form or essence.”

    Yes, this is correct. But I don’t believe I’m overlooking the form. The essential properties of a being are integral to a being. Esse cannot be without essence. The act must be an act of something. But the form — even as determined by matter — is insufficient to explain that which is absolutely unique, e.g., Beethoven.

    As you say, St. Thomas makes a monumental shift away from Aristotle’s doctrine when he uses the act of existing. Indeed, in Aristotle, there can be no appreciation of the person whatsoever. He has no principles that can explain the person. His only option is to rely on material causation. Thus, all individuation for Aristotle proceeds from non-spiritual origins.

    But, because of the act of being, St. Thomas can explain the person as intrinsically unique and of spiritual origins.

  • Victor


    Thanks again for your helpful thoughts. Yes, I think I see more clearly now where we disagree.

    First I agree with you entirely that Thomas and other thinkers can never, as you put it, be “mirrored” and to do so would cause philosophy to stagnate. I would only add, though, that I believe we can recover some of the essential elements of a thinker’s thought, even if we must always be cautious of our historical and cultural contexts, perspective, and biases. I think Gilson is a good example of that insofar as he was able to let the historical Thomas speak more clearly–even if not unmediatedly–than certain essentialist scholastics (such as Cajetan and Suarez whom you mentioned) did.

    Second, I think I appreciate more where you’re coming from now when you say that the act of being is the source (if that’s the correct word) of something’s being unique. However, the difficulty I’ve had in coming to grips with this claim is Thomas’s thesis that esse is not self-determining (hence the passage from De. pot., q. 7, a. 2, ad. 9) but is limited by potency. In fact, this seems to be another area where Thomas differs radically from both Plato and Aristotle, as Norris Clarke has pointed out in his classic work on participation. Indeed, I think what is at issue is something quite at the heart of Thomas’s metaphysics and it is not surprising that there should be some difficulties if not disagreements. This very issue, though not formulated as it is here with respect to personhood, is what divided two of the greatest Thomists of last century, L.-B. Geiger and C. Fabro. How do we understand the relationship between esse and essence vis-a-vis participation, through a participation of similitude or of composition? Both models of participation certainly have strengths that recommend them, but each also has its shortcomings.

    At any rate, you’ve certainly given me something else to consider.

  • Gerald L. Campbell


    This exchange has been very interesting. Thanks. I appreciate your comments.

    I agree completely with your first point. Gilson is a very good example of what you’re talking about — i.e., recovering the essential elements of a thinker’s thought. It would be a tragedy were critical insights, e.g., analogy, lost to oblivion. They are the lifeblood of our civilization.

    “the difficulty I’ve had in coming to grips with this claim is Thomas’s thesis that esse is not self-determining”

    I agree. I see your caution here, and I’m not sure exactly how to address it at this time. Esse is limited by potency, as you say. But what does this “limit” mean? Does the fullness of the esse (the person Beethoven) actuate the being fully at the moment of conception. No. The being evolves over time (nurturing Beethoven, e.g.,) Thus, the form needs to be actuated by material causation (training, discipline, circumstances, intentions, health, etc.). It would seem that the being (Beethoven) needs to be perfected from material as well as the spiritual side to realize the fullness of its potential. The act of being (person) is there, but it’s full impact on the being requires material causation to realize the form. ?????

    The above is a word picture that I’ve written down. I’m not sure what it means at this point.

    As for the esse itself, doesn’t it have a transcendental orientation to a specific being? It seems this would follow from the notion that each act and each being is unique.

    Your comment above in your first post reads: “Again this isn’t to deny the underlying existentialism of Thomas’s metaphysics but to recognize all the more his monumental shifting of Aristotle’s substance ontology to a deeper, existential creation metaphysic–one that preserves substance but grounds it in God’s creative causality.” The phrase “God’s creative causality” stands out here. Is this related here at all?

    Then you quote Maritain, I believe, from P and CG: ““the ultimate achievement by which the creative influx seals, within itself, a nature face to face with the whole order of existence so that the existence which it receives is its own existence and its own perfection.”

    It seems, without being absolutely clear on the matter, this has something to do with what I’m trying to say.

    Sorry for the fog.

    As for L.-B. Geiger and C. Fabro, I have to say I’m not acquainted with them. Participation through similitude vs composition … I can’t recall this debate. But then, it’s been a long time.

    By the way, I didn’t mean to leave out Norris Clarke from the list of people I mentioned above. I should probably review his article on participation again. Ironically, I purchased his book “Explorations in Metaphysics” a couple months ago but haven’t yet had time begin reading it. I notice it has the article on participation and also the one on the limitation of act by potency.

    Thanks again.

  • Victor


    No apologies required for the “fog.” My comment about God’s “creative causality,” was merely to underscore the difference between Aristotle’s substance metaphysic and Thomas’s creationist metaphysics, wherein existence is an utter gratuity bestowed by the divine, not something that follows upon (substantial) form.

    Enjoy “Explorations in Metaphysics.” Clarke is always a worthwhile read!


  • Katerina Ivanovna

    This comment thread is almost worth copying and pasting and making a post of its own.

  • Gerald L. Campbell


    Feel free to do so.

  • professional

    Hello. I think you are eactly thinking like Sukrat. I really loved the post.