Scott Klusendorf offers a brief synopsis of the newly released book, Embryo: A Defense of Human Life by Robert George and Chris Tollefsen.
Here’s a significant plank in the argument:
E) Self-body dualism, as espoused by secular critics, is indefensible. Indeed, there’s a host of problems with the idea of personhood coming into existence only after some degree of bodily development. One is that you end up saying things like “I came to be after my body came to be.” Or, “I inhabit a body that was once an embryo.” Absurd. It’s far more reasonable to say living organism (like human beings, dogs, or cats) are substances that maintain their identities over time and change. What moves a puppy to maturity or fetus to an adult is not an external collection of parts, but an internal nature or essence. Thus, as the human embryo develops, it does not become more of its kind, but matures according to its kind. It remains what it is from the moment it begins to exist even if its ultimate capacities (for example, the ability to think abstractly) are never realized. Likewise, a puppy does not become more of a dog as it matures. Nor does it cease to be a dog if it never develops the ability to bark. True, a human embryo will develop accidental properties (such as self-awareness, size, and physical structure) as it matures, but these properties are non-essential and can be changed without altering the nature of the thing itself. This is why a person can lose a body part and yet retain his personal identity through that change. Applied to the pro-life case, the substance view says that you are identical to your former embryonic self. You were the same being then as you are now, though your functional abilities have changed. From the moment you began to exist, there’s been no substantial change in your essential nature. In short, humans have value in virtue of the kind of thing they are rather than because of some function they perform. You and I are identical to the embryonic human beings we once were–meaning that although you were once small as an embryo, your small size and lack of development did not change the kind of thing you were. You were the same being then as you are now.
