We ended yesterday's post by saying that what we designated Definition (1a) - A person is a living human being with the capacity to engage in acts of intellect, emotion, and will - was problematic. Here's why:
In the course of one’s life it’s possible that an individual becomes comatose. That is, they're in a state of deep unconsciousness from which they cannot be aroused by any stimulation, including pain.
Comas can be either reversible, in which case the individual will eventually come out of it, or irreversible in which case they won’t. Let’s assume for the sake of discussion that medical technology can determine whether a comatose individual will ever be awakened from their coma.
Now here’s a problem with Def. (1a): Whichever form of coma an individual finds himself or herself in, on Def. (1a) the individual is no longer a person and therefore no longer has a right to life.
Some people might agree that an irreversibly comatose individual is no longer a person, but no one would want to say that of a reversibly comatose man or woman. Who wants to say that someone who's temporarily comatose, perhaps under anesthesia, is no longer a person and their rights may be suspended until they recover?
Unconscious or reversibly comatose individuals differ from irreversibly comatose individuals in that they have the potential to recover and exhibit all of the capacities that Singer ascribes to persons. So perhaps we should amend Def.(1a) to accommodate this potential:
Definition (2): A person is a living human being with the capacity or potential capacity to engage in acts of intellect, emotion, and will.
This seems a reasonable definition of a person since it incorporates the characteristics that Singer imputes to persons and also covers those who are reversibly comatose. It will, however, not please those who wish to keep abortion legal at any stage of development prior to birth.
The problem, as those folks will recognize, is that Def.(2) extends personhood all the way back in the chain of development to the conceptus. A human embryo, just like the reversibly comatose individual, is a human being and has the potential to engage in acts of intellect, emotion and will, whether or not it is presently able to do so.
At this point in the discussion someone might object that rather than adding potential capacity we should instead add former capacity.
Definition (2a): A person is a living human being with the capacity or former capacity to engage in acts of intellect, emotion, and will.
This would cover the reversibly comatose as well as irreversibly comatose individuals without conferring personhood on a fertilized ovum or embryo.
The problem is that there seems to be no justification for excluding "potential capacity" except the desire to avoid considering the early stages of human development as persons. Philosophers call this sort of move ad hoc. There’s no independent justification or reason for it other than that it’s necessary in order to salvage one’s preferred position on abortion.
Indeed, since it would seem that in such a serious matter we should adopt the more expansive definition of person rather than the more restrictive definition perhaps the best definition would be:
Definition (3): A person is a living human being with the capacity, potential capacity, or former capacity to engage in acts of intellect, emotion, and will.
But if we accept this definition what we’re saying is that:
Definition (3a): A person just is a living human being.
Note that Def. (3a) does not identify a conceptus, embryo or comatose individuals as “potential” persons. It identifies them as persons. There is, in fact, no such thing as a "potential person" unless one wishes to so regard individual gametes (ovum and sperm) as potential persons.
In conclusion, we’ve looked at six different definitions of a person. Which one, if any, you think is best is up to you to decide.
Of course, one could argue, as many pro-choice advocates do, that even if what's inside the mother's womb is a human being, i.e. a person, the mother should have the right to kill it anyway. That, however, is an altogether different argument than the "no one knows when life begins" argument.