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This is the final installment in a series of pieces looking at arguments from a religious apologist, a Molinist, in answer to my first book, The Unnecessary Science. Previously reviewed and discussed here at OnlySky, the book gives a philosophical and critical look at the thinking of Aristotle and Thomas Aquinas, then modern religious thinkers like Ed Feser who build on those foundations to make moral proclamations in line with their theistic beliefs.

This is the third piece looking at a weightier critique of the book from Justin Kalan of The Molinist. The first piece dealt with the theological wrangles concerning gay marriage, and the second looked at nocturnal emissions and the end of sex in the same religious, natural law context. It is important to deal with such thinking and criticisms because Thomism, natural law, and other similar philosophies underwrite (oftentimes conservative and religious) legal approaches to subjects like abortion, gender, and sexuality.

We will be looking at the definitions of “human being,” a subject that often brings about lively debate.

In The Unnecessary Science, chapter 3.7, I argue that Christian and Thomist philosopher Ed Feser’s Aristotelian argument for an unborn zygote or fetus being an actual human being could just as easily confirm that unfertilized eggs or sperm were also human beings. And this in turn brings down arguments against abortion from the position that zygotes or embryos are human beings (as opposed to human embryos, or human zygotes).

Feser says on p.129 of his book The Last Superstition, if “rationality, locomotion, nutrition, and the like are present even at conception…as inherent potentialities…” in a zygote, then this would make it a human. I argue that those human-defining traits are also present in a sperm or egg cell since those cells have the “potential” to produce those traits no other cells have—it’s just that they require a little more input (fertilization and subsequent gestation) than a fetus requires (more gestation).

In his post, Kalan says the following:

Laird’s claim that both a zygote and egg share the same end is false. The end of a sperm is to fertilize an egg, that of an egg to become fertilized by a sperm and that of a zygote is to develop into a more mature human form. That these three ends are different already tells us that egg, sperm, and zygote are (as is obvious) three different kinds of things rather than all being a human being.

This is not at all convincing. A zygote develops into a “more mature human form” through osmosis, absorbing nutrients directly from the womb, and so on, whereas an actual human child matures by interacting with its environment and getting nutrients through an animal’s means (eating and drinking) rather than vegetative means (direct absorption). We might need to define the term “end” for the next part of the discussion:

Related ends in a given series may be distinguished on the basis of their order of achievement. A proximate end is that for the sake of which something is done directly or immediately. An intermediate end is that in view of which the proximate end is sought and which itself is desired for something else. Both proximate and intermediate ends are also means, each often being referred to as a means-end. The last end in the series is called the ultimate end. A business employee attending night school studies hard to pass a particular course (proximate end). Passing the course will help him earn a degree (intermediate end), which will enable him to get a promotion (ultimate end). An ultimate end is said to be relatively ultimate when the series of which it is the last is subordinate to a higher end or ends. The promotion (relatively ultimate end) may be desired because the salary increase will finance the children’s education (a higher end). The absolutely ultimate end—the supreme end—is that to which all of an agent’s actions are directed and which is sought for its own sake alone. The supreme end of man is happiness.


If Mr. Kalan nonetheless claims, as I assume he would, that a zygote and human child differ merely in terms of their proximate ends (development through osmotic nutrition as opposed to development through nutrition by eating and drinking) rather than their most ultimate end, it’s trivially easy to make the same argument for sperm and eggs: The proximate end of those cells might be fertilization, but the end of fertilization is for them to develop into a more mature human being, just like the proximate end of a zygote might be osmotic absorption of nutrients, but the ultimate end of that is to continue developing into a more mature human being.

This point is reinforced when we examine Kalan’s further claim:

When fertilization is accomplished, both egg and sperm cease to exist as egg and sperm and a new kind of thing comes into being, namely a zygote which is a new human organism. The fact that the egg and sperm cease to exist is important. It is not true to say that a sperm develops into a zygote and then to a fetus and then to a teenage and so on. The sperm exists to fertilize an egg. Once this has been done, the sperm has reached its end and a substantial change has occurred resulting in the existence of a new substance which is neither a sperm nor an egg.

It is, to put it mildly, not exactly obvious that either the sperm or the egg have “ceased to exist” at the moment of fertilization. You could argue they’ve been completed, but not that they’ve abruptly ceased to exist and been replaced by a new substance. The most important parts of the two cells—the mother’s X chromosome in the egg and the father’s X or Y in the sperm—remain present in the newly-fertilized zygote.

We could have discussions here of the existence of abstract ideas, such as “sperm” or “egg,” and whether those ideas exist anywhere outside of our own conceiving minds. This is called conceptual nominalism and is discussed in the book. Conceptual nominalism, outside of this debate, is also arguably a defeater for such Thomist positions.

Nevertheless, that aside, there thus seems to be a continuity between the zygote and its sperm and egg, with the zygote’s internal organization, and thus “intrinsic principle of growth,” building or expanding on the intrinsic principles the sperm and egg provided to it. This is a stark contrast to other examples of substantial change, such as those involving destruction. If you burn down a tree, the wood has substantially changed to ash, or in other words, the tree has been destroyed and then replaced with an equal amount of ash. This is because the resulting substance, dead ash, has completely different powers and principles of operation than a living tree. There is no continuity there, at least not in the same sense and to the same degree. Since there is continuity between an unfertilized and fertilized cell, it seems to me that an Aristotelian ought to maintain there has been no substantial change, and thus the unfertilized cell is also a human being, merely a less developed one.

I also note that this seems absurd (p. 155), and Mr. Kalan would agree, so the Aristotelian needs to be able to mark off a specific moment when we can speak of an actual human being from a common-sense perspective as opposed to a couple of cells or a mere bundle of cells. In The Unnecessary Science, I marked that specific moment as birth, or even more particularly, the cutting of the umbilical cord, arguing that a fetus did not become a human baby until that moment as it previously took in all its nutrients from its mother’s body, thus lacking the intrinsic principle of self-development an individual human substance would have. Mr. Kalan disagrees, and in this case, reviewing my work, I believe the reason lies in a poor choice of words I didn’t catch on my final revision passes.

Mr. Kalan quotes me from p. 155 of The Unnecessary Science:

A zygote is not really like an adult cat or dog or squirrel or other animal Feser uses as examples of natural substances. A grown independent animal is capable of taking in nutrients, reproducing, and carrying out all its other behaviors…on its own volition and does not necessarily rely on any other entity to do it for them. In other words, these animals operate entirely according to their intrinsic principles…A zygote, on the other hand, relies entirely on its mother’s body to carry out its distinctive operations.

He responds by saying the following:

The fact that some animals have their own volition and can hunt or forage for example does nothing to distinguish them from other living things qua living things. Does he think that on the Aristotelian view that bacteria, grass, and jellyfish are not truly natural substances because they lack volition? It is of course true that a zygote or a fetus takes in nutrients from its mother’s body just as a plant does but that does nothing refute the fact that each operates by an intrinsic principle. It is precisely because they function in accord with such a principle that these organisms take in nutrients as they grow and develop.

Now, in that section of The Unnecessary Science, I was responding to the examples Feser used in his own work, which were all animals. Volition—moving oneself, choosing between various possible objectives (eating one type of food over another, advancing towards a possible meal versus fleeing from a predator, etc)—is part of what often defines an animal. However, the concept of an intrinsic principle, as Mr. Kalan notes, is much broader than that, and thus I should have used a broader term than “volition.” This is my fault for being a bit hyperfocused on the examples Feser originally used. There are a couple of other small errors in the final draft of The Unnecessary Science, and I might correct them along with this omission if I ever make a second edition.

With that out of the way, my corrected statement would read as this:

The phrase “under its own power” better reflects the broader idea of an individual organism having its own internally-powered operations (as opposed to volition, which applies to animals specifically), and “organism” is more specific than “entity,” which can apply to anything that exists and thus might confuse readers. And thus we have an easy riposte to Mr. Kalan’s supposedly incisive critique. Yes, bacteria, grass, and jellyfish don’t have volition (in fact, you could say they are merely “vegetative” in Aristotle’s sense even though bacteria and jellyfish aren’t plants), but they do not require the help of some other separate organism to fulfill their functions. A blade of grass or jellyfish floating through the sea absorb nutrients entirely on their own power (water in the soil in the first case, organic detritus in the second). They don’t rely on some super-organism to do this, though they may die in periods of drought or famine or whatnot. On the other hand, a fetus is dependent on another organism, its mother, in a way an independent substance is not. If the mother dies, the fetus dies, unless it is detached from her in time and set up in an incubator. And, surprise surprise, that moment of detachment is precisely when I aver a fetus can no longer be considered a mere part of its mother’s body but an individual human substance on its own. For a second time, it seems Mr. Kalan has strengthened my arguments rather than refuting them.

Now, Mr. Kalan continues, objects to my thesis that there is some gain of intrinsic powers caused by the severance of the umbilical cord. According to him, a fetus does indeed influence its environment as an active actor in its own way:

Evidently the mothers’ large bellies, their pain caused by their child’s various positions, their change in appetite, smell, and a hundred other changes were purely the result of their own volition. After all, their babies had no control over their environment!

It is true that these changes aren’t due to anything the mother willed (or the fetus, as it’s not yet intelligent and thus can’t will anything). Mr. Kalan does not seem to have grasped the point I was making, however, and again this is my fault for concentrating too much on animal examples specifically and using the term “volition” when I should have used the more general term “power.”

The point I was making was that the various painful and inconvenient changes a pregnant mother experiences are ones her body is carrying out as it actively works to keep its cargo alive. As I state a few sentences later (but Mr. Kalan does not quote), “Even a developed fetus, no matter how much it kicks or rolls around in the womb, cannot change the chemicals of the uterus surrounding it, nor how many nutrients the uterus provides it” (p. 159). A fetus can hurt and trouble its mother a great deal, but no action it takes will cause its mother’s body to give it more or less nutrients. The chemical changes a mother’s body experiences are powered and directed by the mother, not the fetus, as the fetus is not providing any nutrients of its own to power the various immunological, hematological, etc. changes the mother’s body makes to again protect its cargo.

This is, again, a stark contrast to an actual baby’s behavior: Baby Stewie’s actions can directly lead to Lois feeding him or not feeding him when he cries (indicating hunger) or slaps the bottle away from her (indicating he’s full). Thus, I maintain the assertion that birth, and the severance of the physical umbilical connection between a mother and fetus, marks the precise moment when a fetus is substantially changed into a human individual, as evinced by the baby’s assumption of active powers contrasted to the purely passive, nutritive, dependent powers of a fetus.

So, in the end, while I thank Mr. Kalan for highlighting a technical error I didn’t catch in my final revisions, I cannot regard his objections to any of my arguments as fatal or even that intriguing, though I do commend his inventiveness in bringing up sleep-talking and walking (discussed in the previous pieces). He states he may write more entries to critique my book, in which case this may not be the last piece I write on the matter. While I thank Mr. Kalan for his time, I feel that the Thomistic approach to all of the matters mentioned in this series is still lacking.

A TIPPLING PHILOSOPHER Jonathan MS Pearce is a philosopher, author, columnist, and public speaker with an interest in writing about almost anything, from skepticism to science, politics, and morality,...

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