Was having a conversation by e-mail yesterday with a pro-abortion atheist, and he gave two reasons why he supported abortion in the first and second trimester. First, he said that unborn babies can’t feel pain, so it’s OK to kill them. Second, he said that unborn babies don’t have consciousness, so it’s OK to kill them. I thought it might be useful to link to something that answers both of these objections.
Frank Beckwith is the author of “Defending Life: A Moral and Legal Case Against Abortion Choice“. He wrote that book for Cambridge University Press, a top academic press. But before Cambridge University Press, Beckwith wrote four easy-to-understand essays for the Christian Research Journal. Part IV is the one that has the response to the two questions raised by my atheist friend.
Part I. The Appeal to Pity
Part III. Is The Unborn Human Less Than Human?
Part IV. When Does a Human Become a Person?
Some ethicists argue that the unborn becomes fully human sometime after brain development has begun, when it becomes sentient: capable of experiencing sensations such as pain. The reason for choosing sentience as the criterion is that a being that cannot experience anything (i.e., a presentient unborn entity) cannot be harmed. Of course, if this position is correct, then the unborn becomes fully human probably during the second trimester and at least by the third trimester. Therefore, one does not violate anyone’s rights when one aborts a nonsentient unborn entity. 
There are several problems with this argument. First, it confuses harm with hurt and the experience of harm with the reality of harm.  One can be harmed without experiencing the hurt that sometimes follows from that harm, and which we often mistake for the harm itself. For example, a temporarily comatose person who is suffocated to death “experiences no harm,” but he is nevertheless harmed. Hence, one does not have to experience harm, which is sometimes manifested in hurt, in order to be truly harmed.
Second, if sentience is the criterion of full humanness, then the reversibly comatose, the momentarily unconscious, and the sleeping would all have to be declared nonpersons. Like the presentient unborn, these individuals are all at the moment nonsentient though they have the natural inherent capacity to be sentient. Yet to countenance their executions would be morally reprehensible. Therefore, one cannot countenance the execution of some unborn entities simply because they are not currently sentient.
Someone may reply that while these objections make important points, there is a problem of false analogy in the second objection: the reversibly comatose, the momentarily unconscious, and the sleeping once functioned as sentient beings, though they are now in a temporary state of nonsentience. The presentient unborn, on the other hand, were never sentient. Hence, one is fully human if one was sentient “in the past” and will probably become sentient again in the future, but this cannot be said of the presentient unborn.
There are at least three problems with this response. First, to claim that a person can be sentient, become nonsentient, and then return to sentience is to assume there is some underlying personal unity to this individual that enables us to say that the person who has returned to sentience is the same person who was sentient prior to becoming nonsentient. But this would mean that sentience is not a necessary condition for personhood. (Neither is it a sufficient condition, for that matter, since nonhuman animals are sentient.) Consequently, it does not make sense to say that a person comes into existence when sentience arises, but it does make sense to say that a fully human entity is a person who has the natural inherent capacity to give rise to sentience. A presentient unborn human entity does have this capacity. Therefore, an ordinary unborn human entity is a person, and hence, fully human.
Second, Ray points out that this attempt to exclude many of the unborn from the class of the fully human is “ad hoc and counterintuitive.” He asks us to “consider the treatment of comatose patients. We would not discriminate against one merely for rarely or never having been sentient in the past while another otherwise comparable patient had been sentient….In such cases, potential counts for everything.” 
Third, why should sentience “in the past” be the decisive factor in deciding whether an entity is fully human when the presentient human being “is one with a natural, inherent capacity for performing personal acts?”  Since we have already seen that one does not have to experience harm in order to be harmed, it seems more consistent with our moral sensibilities to assert that what makes it wrong to kill the reversibly comatose, the sleeping, the momentarily unconscious, and the presentient unborn is that they all possess the natural inherent capacity to perform personal acts. And what makes it morally right to kill plants and to pull the plug on the respirator-dependent brain dead, who were sentient “in the past,” is that their deaths cannot deprive them of their natural inherent capacity to function as persons, since they do not possess such a capacity.
These four essays are a very good introduction to common responses to pro-abortion arguments. I recommend that people get familiar with this, as once you look into it, you will see that the abortion issue can be debated with as much confidence as William Lane Craig defends Christian theism. You will have the same access to scientific evidence and rational arguments on this topic, and so you will have the upper hand. And that’s fun.
The best introductory book on the abortion / right to life issue is “The Case for Life” by pro-life debater Scott Klusendorf. The best comprehensive book is a tie between “The Ethics of Abortion” by Christopher Kaczor, and Frank Beckwith’s “Defending Life: A Moral and Legal Case Against Abortion Choice“.