An embryo is just a clump of cells
An embryo is a cluster of cells. Physically speaking, so are you and I. This doesn’t prove much. What matters is that these cells are developing along the normal path of human development and constitute a human organism.
Yes a zygote is human, but then again, aren’t all human cells composed of human DNA?
This is true. However, simply being composed of human DNA is not what makes a thing a human being. It is true that the fact that a zygote is made up of human DNA is one reason why we consider it a human cell. Also, the fact that this DNA is unique is good reason to believe it is distinct from both its mother and father. The fact that the new set of DNA comes into existence usually with the fertilization of the egg with a sperm cell might be good evidence of a clear cut dividing line for when the life of a new human begins. However, being composed of DNA alone does not make a thing a complete human being.
The two main reasons why a zygote is considered human are as follows: (1) there is no other clear dividing line between a zygote and an adult human. Development is a gradual process and there is continuity between an adult and a zygote. This seems to show (with of course further argument) that both things have the same intrinsic nature albeit are at much different stages of their existence hence have different characteristics. (2) The zygote functions as a complete organism. After we have determined, from the fact that it is composed of human DNA for instance, that it is a human cell, we have to determine if that cell is a complete organism, in its own right independent, or if it is really just part of another organism like heart tissue for instance. One reason for holding that a zygote is its own being is that its activity is directed towards its own survival, growth, and development. It certainly depends on the mother for this, however, unlike organ tissue, it is not acting to support the survival, growth, and development of the mother. Another reason is that under ordinary circumstances, in a proper environment, the tissue of another organ (say heart tissue) would not develop into an adult human whereas under the proper circumstances, a zygote would. This shows that it is intrinsic to the nature of the zygote to develop like an early human would whereas this is not true of other human tissue even though it is composed of human DNA.
One might object that we could at least hypothetically manipulate these other cells in such a way that they would develop according to the path of human development. This would undermine the claim that the zygote is somehow unique. The problem with this objection is that it misses the key point. The other cells would need to be manipulated in some way in order to go on the path of human development. Given how they are now they could not do this. It is not within the nature of the cells themselves to become an adult human and act as complete organisms. They need to be changed in some way. If this change does occur, then the cells would act like human organisms. This however would just mean that they, like the ordinary zygote, would be human beings. This would just be a kind of cloning. However as is, the cells, like gametes, only have potential to become humans and need a special change in order to actually become human. The zygote on the other hand however is the product of this change and already is a human being.
Not all humans come into existence with sperm-egg fertilization, doesn’t this undermine the “life begins at conception”?
The phrase “life begins at conception” is misleading because what we are really concerned with is when does the life of a human being begin, not when does life begin or when do human cells begin. Life is continuous since the beginning of life on earth. The sperm and egg are alive and genetically human (although they only contain half of the chromosomes of normal somatic cells).
In any case, the proper position is that the “life of a human being begins at conception.” Yet this is only a generalization based on how most humans come into existence. That is, when a sperm fertilizes an egg, a new human being comes into existence. However, given different circumstances, a new human being could begin at a different point. For instance, in human cloning or in twinning, fertilization is not necessarily the point at which a new human exists. The real issue then has less to do with when does life begin as what type of think counts as a human being. Ordinarily, fertilization is a dividing line between what counts as a human being and what does not in the course of a human’s developmental history. However, this is not always true. In other cases, other biological events may result in a new human organism. These biological events would have a relevant similarity to fertilization although they would not be the same. This does not undermine the pro-life position because the argument of the pro-life position relies on what the zygote-embryo-fetus is not when it began to be that way. The beginning point is only important insofar as it makes a human being when there was none before, hence what matters is not the precise mechanism but the relevant similarity, namely, the production of at least one human being when that human did not exist before.
An embryo doesn’t look like a human at all, it is absurd to say that it is
Actually, we have to determine what an embryo is before we determine what it looks like. Given that there are reasons which support an embryo is a human being, then our stand should be that an embryo does look like a human being, albeit one at a very early stage in development. But this shouldn’t come as a shock because we shouldn’t expect a human at the very earliest stages in development to look like a typical adult.
If you had a choice to save ten embryos or one typical adult human, wouldn’t you save the one adult?
This is an attempt to appeal to intuition about the value of embryos. The problem is that intuition isn’t always entirely correct and therefore should only be a rough guide in cases of morality, not an absolute. This intuition is probably present in most people, but this is probably the case because of how we relate to adults versus how we relate to embryos (that is, we don’t have any direct experience of them).
In any case, we ought to evaluate the morality of this decision based on the knowledge that embryos have rights (because we can argue this fact independent of intuitions). And then we can see how this intuition fits in to the big picture.
That said, I wouldn’t necessarily deny that I would chose to save the one adult. I certainly would hold that it is immoral to directly kill the embryos (for example using the destruction of embryonic stem cells as a means to develop cures for diseases). On the other hand, if there was a scenario where I could only save the ten embryos or the adult human, the situation is different. The reason is that this involves the weighing of different factors besides the value of the embryos and adults. In this instance, there is no question of rights because there is no direct killing. Therefore, in my balance of who to save, I would have to factor the possible futures of all of the persons involved, the chances of me saving them, the other people effected by the loss, etc. This is no surprise considering the problem arises if we postulate a situation between adults. For example, if I had to choose between saving ten strangers versus saving my own mother, I would save my own mother, and I don’t think I would act wrongly. In this case I do not take the position that the other ten are of less value, but in this case, I still would rather save the person close to me for other reasons.
A zygote-embryo-fetus isn’t a human, it’s just a potential human
This is simply incorrect. The zygote is a potential adult human. However, it is a potential adult human in virtue of it already being a human.
An embryo is neither a human nor not a human, it is whatever the woman wants it to be
This stance is equivalent to saying that an embryo is not a human. An embryo is either a human or not a human as this covers all logical possibilities. To deny this is to deny the law of excluded middles. If we say that an embryo is whatever the woman wants it to be, we are implicitly committing ourselves to the claim that an embryo is objectively not a human being because if it were, ‘whatever the woman wants it to be’ would have no force in deciding this fact as it would be an objective human no matter what. Hence this objection comes down to just: “an embryo is not a human being.” Yet this is just what we deny when we argue that it is using some general philosophical assumptions about life and some basic biology.
Since such a large portion of embryos fail to implant or spontaneously abort, isn’t it an odd view to say that they are humans?
There are a variety of numbers thrown out about how many embryos fail to implant and how many spontaneously abort without the mother knowing, etc. One problem right off the bat is how can we get this data if the woman doesn’t even know she was pregnant…this seems to pose a major problem for collecting data.
In any case, even if this were true, it doesn’t show that what dies isn’t human, only that many humans die a lot earlier than we would ordinarily assume.
Finally, one might think that this raises a theological problem because it is not clear why God would create a world where so many humans die without even seeing the light of day. Still this is not terribly more difficult to understand then understanding why God created a world in which for most of human history significant numbers of infants died in the first few weeks and months of life. In and of itself early infant death no more proves infants are not human than early deaths of embryos proves embryos are not human. I admit why God created a world were such things occur isn’t a question that is answered easily, but then again, the mind of God is far beyond any human understanding. This itself is just one more way of posing the problem of evil. “Why does God allow evil X?” The question ultimately comes down to the mysterious relationship between sin and suffering and how God allows evil for the sake of bringing about a greater good. If there is independent reason to believe God exists and He is good we ought not to abandon our reasoning because of tough questions.
Doesn’t the possibility of identical twins undermine the argument that life begins at fertilization?
There are two reasons why someone might think this is the case. First, because it contradicts the idea that “life begins at conception.” We have already examined this objection. Second, because it undermines the idea that each human is genetically unique. The problem is that this isn’t essential to the pro-life position. Genetic uniqueness can help demonstrate that the zygote is neither the mother nor the father, which helps show that it is a new human being that is distinct. However, the genetic uniqueness isn’t essential in order to be a human being. Hence an identical twin comes into existence when the embryo divides in such a way as to bring about a separate organism, that is, one that starts to develop independent of the other.
Well that concludes this series in defense of the pro-life position. Let’s continue to pray for the unborn children of this world that their right to life may be recognized by the governments throughout the world: