It's quite possible for a human being to freeze to death in an extremely hot place. That sounds weird, but it's true if you define a hot place as one that has a high temperature.
Temperature, you see, is defined quite rigorously as a measure of the average kinetic energy of the atoms or molecules in a region of space. But that is not the only factor that determines the rate of heat gain or loss from the body.
Suppose you go to a place where the temperature is, say, 10,000 K, but the ambient pressure is very low and there are no effective sources of radiant energy nearby. Such a place might be found, for example, on the shady side of a sturdy umbrella in space near a hot young blue giant star. A person finding himself there would be bombarded by very fast-moving particles, but so few of them that the total energy they added to his body would not begin to compensate for what he was losing by radiation. So he would freeze to death.
His parting impression of the place would be that it felt cold, not hot. The sensation of "hot" or "cold" is not so much a measure of ambient temperature as of the rate at which thermal energy is being gained or lost by the body. (More familiar examples are the "wind chill factor" and the extra-cold feel of metal objects on cold days.) This is really the quantity of more interest to the body. Our freezing spaceman would find little consolation, or clue as to how to save himself, in the knowledge that the near-vacuum around him had a temperature of 10,000 K.
I bring all this up only as a rather striking example of how we can get used to using a word to mean A when it really has a more complicated meaning B which happens to reduce to A in a particular context. When we enter a different context, we tend to forget the real meaning B and mistakenly assume that A is still the appropriate interpretation. We tend to equate "feels hot" with "has a high temperature'' because those two qualities correlate pretty closely under most familiar conditions, such as still air in a well-insulated room of controlled humidity. If pressed, we'll admit that the correlation falters a bit when winds and humidity and thermal conductivity enter the picture, but the discrepancies are small enough that most of us (hypothermia victims excepted) tend to shrug them off. My freezing spaceperson example illustrates that the discrepancies can be much more than academic quibbles.
There are plenty of other examples, such as the common tendency to equate "pitch" with "frequency," even though pitch is really influenced, sometimes drastically, by several other factors. The one which is my main subject for the day has to do not with curiosities of physiological sensation, but rather with a controversy which has been very much in the public eye for several years. I'm speaking of the controversy over when, if ever, women should be allowed to have abortions.
I am not going to say that either of the extreme answers is The Right One; my opinion on that is of little importance to the world at large. What is important is that both sides should clearly understand what it is that they're debating, and in many cases they do not. Opposition to abortion is commonly identified with the phrase "Right to Life," while proponents of abortion question the existence, or at least the extent, of such a right.
Yet I can't offhand recall a single such discussion in which the right to life was actually the subject discussed, even though that was the word used.
There are people who genuinely believe in a right to life, at least for members of the animal kingdom. Such a belief is an important tenet of some eastern religions. But I've known very few "right-to-lifers" in this part of the world who consider it murder to squash a cockroach, and only a few more who had serious objections to trapping mice or catching a trout for breakfast while camping. Again, I'm not talking about my personal views; I have on occasion annoyed people by refusing to kill spiders, but that's neither here nor there. My sole intent here is to examine the logical consistency of opposing abortion on grounds of "right to life," and debating the issue in terms of when life begins. Since most people who do so see nothing particularly troublesome about killing many things which are clearly no less alive than any fetus, they do not really recognize a right to life. So I must conclude that when life begins is not the issue.
The issue, I think, is when humanity begins.
But what is that?
John W. Campbell tackled that one several years ago, in a lovely piece of thought provocation titled, "What Do You Mean—Human?" (recently reprinted in our Readers' Choice anthology). He came up with more questions than answers; among other things, he showed that various "obvious" and seemingly valid tests that might be proposed for "humanness" would rule out idiots, babies, or pirates with wooden legs, but admit robots or chimps. He did not come up with a test that gave all the "right" answers, according to our prevalent prejudices. Nor did he consider the application of his tests to unborn babies.
I don't know any biologist who would say that there is any question of whether fetuses or embryos are alive. (For convenience, I shall use the two terms interchangeably; the common distinction between them is really part of what's at issue here, anyway.) Any fetus (except a dead one), regardless of state of development, is quite clearly alive. (For that matter, by most definitions, so are isolated but viable ova and spermatozoa.) What people are really arguing about is, when does the fetus become human?
Let me propose for consideration at least a partial answer—if not to the large question of "What is human?", at least to the more immediate, operational one of, "When should a fetus be treated as human?" The key to my suggestion is an idea first proposed (somewhat crudely) by the nineteenth-century German biologist E. H. Haeckel: that "Ontogeny recapitulates phylogeny." The idea, simply put, is that the stages through which an individual organism develops correspond, at least approximately, to the stages of evolution which led to its species. Human embryos, for example, are well known to go through stages with tails and gills.
Later biologists, of course, recognized Haeckel's notion as a gross oversimplification. Recapitulation is not literal or exact; at no time does a human embryo closely resemble an adult fish, amphibian, or reptile. However, there are stages at which it is very similar to the corresponding embryonic stage of a fish, amphibian, or reptile. Only later does it diverge to become distinctively human.
So my proposal is this: at a stage when an embryo closely resembles that of another species, it deserves the same level of ethical consideration you would give to that species. At an amphibian-like stage, for example, you are justified in doing unto it as you would do unto a salamander. If one embryo is essentially indistinguishable from another, there seems to be no reason to treat them differently. If one is less than human and therefore deserving of less respect or protection, the other is equally so. If you believe it's all right to destroy salamanders, you may have to admit the same for human fetuses at the "salamander" stage of development. If you don't believe it's all right to destroy such fetuses, you may have to rethink your attitude toward salamanders.
If you reject the concept of evolution, this may seem instant grounds for rejecting my proposal, but in fact it does not depend on evolution, even though the idea originated there. Nobody accepts "Ontogeny recapitulates phylogeny" literally any more, anyway. My proposal does not depend on viewing a given embryonic stage as in any real sense mimicking an "evolutionary" stage, but only on recognizing its essential similarity to the corresponding stage of other, "lower" animals.
To certain types of "right-to-life" advocates, of course, even that will be violently unacceptable. Such a person might object that the human embryo is fundamentally different at every stage, by virtue of something he might call a soul. This may well be, but if it's going to be the basis of public policy we need reliable, provable methods to tell whether or not an entity has a soul. We also need answers to other questions, like, at what point does a fetus acquire one? I have never heard anyone claim that an egg or sperm cell had a soul, and at the instant of conception there is little more than the fusion of the two. Does a soul spring full-blown into being at that instant? Or is it genetically programmed to appear at some later point? Are souls quantized, in the sense that either you have one or you don't? Or do souls, like the rest of us, undergo progressive stages of maturation?
Someone with a less theological and more biological bent might ask similar questions in different language. As a biologist friend of mine put it, a human embryo is different from analogous forms of other species—quite demonstrably and unequivocally—at a microscopic level. Even though it is momentarily quite similar in macroscopic form and physiological functioning to its "lower animal" analogs, its DNA carries a full set of genetic programming which, given the chance, will eventually transform it into a functional human being.
This is pretty clearly true. Furthermore, it is true all the way back to the instant of fertilization. If this is your criterion for humanity, and if you believe that human lives, whether "potential" or "actual," must never be destroyed, then the right-to-life advocates have won at least a good part of their case.
But to what extent is "potential" humanity (like that of a one-month embryo) equivalent to "actual" humanity (like yours or mine)? Does having the genetic potential to become functionally human mean that an embryo is human, or is humanity only earned when a certain amount of that potential has been achieved? One who believes that no ethical distinction can be made might reply with an analogy: destroying a photographic negative destroys a picture as genuinely and permanently as destroying a print—perhaps even more so, if no prints have yet been made. To the photographer, it doesn't even matter very much whether the film has been developed to the negative stage. If he has composed the picture and exposed the film, but loses it on the way to the darkroom, there is still a sense of loss.
But that loss is, in general, at least somewhat less than if he had actually seen the picture, instead of just knowing that the information to produce it was recorded somewhere.
How valid is that analogy? I don't know. I know it's not perfect; perfect analogies are called "identities." But analogies are possible only because some similarities actually exist between the things being compared.
The exact meanings and relative values of "potential" and "actual" are important subsidiary questions. The central issue in the "right-to-life" controversy remains, not "When does life begin?" but "When does humanity begin?" In his story elsewhere in this issue, Timothy Zahn considers that question from another point of view. Neither of us presumes to have The Final Answer, and I think we both suspect that the answer is not simple. My hope, for now, is just that we all get clearly in mind exactly what the question is, before we get too violent with each other over answers.