In the Catholic Tradition does there exist a teaching on the purpose or role of the human soul in the makeup of a human being? I could also settle for a theologian's thoughts and writings on the subject as well.

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    Background: I was reading an article recently where an abortion doctor claimed to rationalize his practices on him 'not knowing when a baby receives a soul'. As sketchy a rationale as it is, I am attempting to reason that a soul of some kind is necessary for life to begin and progress- hence the necessity of a soul at conception. For this to be possible, the Purpose of a soul would have to be established. If my thinking proves right, you could deduce that this doctor's (bad) rationalizing is in fact flawed. Jul 30, 2015 at 16:57
  • The doctor may have been aware of earlier Catholic doctrines that held the soul entered when the embryo 'quickened' or at some other time before birth. These doctrines are now abandoned by the Church. Jul 30, 2015 at 21:57
  • The human (intellectual) soul is how we are made in God's image.
    – Geremia
    Jul 31, 2015 at 3:05
  • @DickHarfield The theory of progressive ensoulment was never Church doctrine, but only St. Thomas Aquinas’ theory (which he based, in turn, in Aristotle’s rather erroneous embryology). In fact, the Church even today does not take a firm position on when ensoulment occurs, since it is a philosophical question. Knowing what we know now about embryology, I think the case can convincingly be made that ensoulment is immediate from the moment of conception. Be that as it may—even if ensoulment were progressive—abortion would remain a most grave offense. Sep 9, 2016 at 7:04

2 Answers 2


The Catechism of the Catholic Church has this to say with regard to the soul itself:

In Sacred Scripture the term "soul" often refers to human life or the entire human person. But "soul" also refers to the innermost aspect of man, that which is of greatest value in him, that by which he is most especially in God's image: "soul" signifies the spiritual principle in man. [363, emphasis in original]

The Catechism emphasizes the unity of the spirit and the body, saying that man "is a being at once corporeal and spiritual" (362), and that "spirit and matter, in man, are not two natures united, but rather their union forms a single nature" (365). Perhaps most relevant to your question, the Catechism teaches that the human body "is a human body precisely because it is animated by a spiritual soul".

Thus, it's not surprising that the instruction Dignitas Personae (2008) deals with the issue of the personhood of embryos the way it does. Quoting Donum vitae, it reads in part:

Although the presence of the spiritual soul cannot be observed experimentally, the conclusions of science regarding the human embryo give “a valuable indication for discerning by the use of reason a personal presence at the moment of the first appearance of a human life: how could a human individual not be a human person?”. Indeed, the reality of the human being for the entire span of life, both before and after birth, does not allow us to posit either a change in nature or a gradation in moral value, since it possesses full anthropological and ethical status. The human embryo has, therefore, from the very beginning, the dignity proper to a person. [emphasis added]

N.B. Some have taken the church's teaching of creationism of the soul (see Catechism 366) and argued that we don't know when God creates the soul in each person. That's likely the argument made by the abortionist you mention, but it's also the exact argument rebutted in Dignitas Personae. Human embryos, according to Roman Catholicism, are always human persons, and thus have souls from their very beginning.

  • This is exactly what I was looking for. Thank you for this answer. It also heartens me that I perceived part of your answer (likely an intuition given to me by a general Catholic world view) to be the Truth of things. Jul 30, 2015 at 18:14
  • @shiningcartoonist If said doctor performs abortions on the ground that we don’t know at what moment the embryo begins to have a rational soul, he is on morally shaky ground. With that logic, a hunter could justify shooting at anything that moves, on the grounds that he “doesn’t know whether it is a man or not.” Sep 9, 2016 at 6:59

The Council of Vienne (1311-1312), under the authority of Clement V, defined the dogma that the soul is the form of the human body (Denzinger 481):

Moreover, with the approval of the said council, we reject as erroneous and contrary to the truth of the catholic faith every doctrine or proposition rashly asserting that the substance of the rational or intellectual soul is not of itself and essentially the form of the human body, or casting doubt on this matter. In order that all may know the truth of the faith in its purity and all error may be excluded, we define that anyone who presumes henceforth to assert defend or hold stubbornly that the rational or intellectual soul is not the form of the human body of itself and essentially, is to be considered a heretic.

"Form" is "the actualizing principle that makes a thing to be what it is." Thus, a body without the substantial form of a human being (a soul) is a corpse.

The Oxford English Dictionary defines form as:

In the Scholastic philosophy: The essential determinant principle of a thing; that which makes anything (matter) a determinate species or kind of being; the essential creative quality.

This use of form (Aristotle's μορϕή or εἶδος) and matter (ὕλη) is a metaphorical extension of their popular use. In ordinary speech, a portion of matter, stuff, or material, becomes a ‘thing’ by virtue of having a particular ‘form’ or shape; by altering the form, the matter remaining unchanged, we make a new ‘thing’. This language, primarily applied only to objects of sense, was in philosophical use extended to objects of thought: every ‘thing’ or entity was viewed as consisting of two elements, its form by virtue of which it was different from, and its matter which it had in common with, others.

Read St. Thomas's short work On the Principles of Nature (De principiis naturæ) for more information on matter and form (hylemorphism).

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