Pro-lifers want to know: when does life begin? Is it at conception? What about birth? Somewhere inbetween?
Biologists have trouble defining life, too. Is a virus alive? What about a toenail? The difficulty for biologists is constructing a definition that corresponds to everything that seems alive, from a commonsense standpoint, and excludes everything else. They want to keep plants in, but rocks out.
Why not just go with the Wikipedia definition? After all, Wikipedia typically reflects a consensus, right? Here’s Wikipedia’s version:
- Organization – Living things are comprised of one or more cells, which are the basic units of life.
- Metabolism – Metabolism produces energy by converting nonliving material into cellular components (synthesis) and decomposing organic matter (catalysis). Living things require energy to maintain internal organization (homeostasis) and to produce the other phenomena associated with life.
- Growth – Growth results from a higher rate of synthesis than catalysis. A growing organism increases in size in all of its parts, rather than simply accumulating matter.
- Adaptation – Adaptation is the accommodation of a living organism to its environment. It is fundamental to the process of evolution and is determined by the individual’s heredity.
- Response to stimuli – A response can take many forms, from the contraction of a unicellular organism when touched to complex reactions involving all the senses of higher animals. Plants also respond to stimuli, but usually in ways very different from animals. A response is often expressed by motion: the leaves of a plant turning toward the sun or an animal chasing its prey.
- Reproduction – The division of one cell to form two new cells is reproduction. Usually the term is applied to the production of a new individual (either asexually, from a single parent organism, or sexually, from two differing parent organisms), although strictly speaking it also describes the production of new cells in the process of growth.
This is a pretty stock definition. All six qualities are necessary for life to exist. But how can we apply them to a fetus in the womb? A fetus has cells, it metabolizes, it grows, and it responds to stimuli. Adaptation and Reproduction are the sticky issues. How can a fetus adapt? Well, it grows into an adult human, reproduces, and the fittest children survive. But how do we decide whether a 2-week versus a 6-month fetus is “alive” by this criterion? We can’t. The biological definition of life doesn’t help us determine at what stage a fetus is living. Same applies to reproduction. Except there’s this curious addition to the reproduction quality: “strictly speaking it also describes the production of new cells in the process of growth.” Does it?
Let’s take a look at the World Book Encyclopedia’s definition of “Reproduction”:
Reproduction is the process by which living things create more of their own kind. There are two major types of reproduction-asexual and sexual. In asexual reproduction, a new organism develops from one existing organism. Some lower organisms, including bacteria, reproduce asexually. In sexual reproduction, a new organism develops from the union of two sex cells. In most cases, these cells come from two parents-a male and a female. Human beings and most higher animals and plants reproduce sexually.
No mention of reproduction as the process of creating new cells here. Why was that portion added to the Wikipedia entry? If you look at the history of the entry, you’ll find the reproduction quality has been edited repeatedly. Clearly it’s a point of contention among Wikipedia authors. Note also, the next section which qualifies the definition: “It is important to note that life is a definition that applies at the level of species, so even though many individuals of any given species do not reproduce, possibly because they belong to specialised sterile castes (such as ant workers), these are still considered forms of life.” This appears to contradict the Wikipedia definition of reproduction, for obviously even worker ants produce new cells in the process of growth. But this also suggests that the biological definition of life is not useful in determining the ethics of abortion, because there are many exceptions to these rules so that we can fit in our common sense idea of what is alive. No one agrees that a mule is not a life form, so we need to adapt our definition to the phenomenon.
Most important, though, is this phrase: “life is a definition that applies at the level of species.” You can’t apply the definition to an individual member of the species — the biological definition of life doesn’t work that way.
Clearly the biological definition of life is irrelevant to the question of abortion ethics, because it can’t be applied at the level we’re interested in: is a 6-month fetus alive, is a 6-week fetus alive, and so on. It’s pointless debating it.
And that’s all I have to say about the beginning of life from a biological perspective. Let it henceforth be known that when I’m talking about a “living human being” in the context of the abortion debate, I’m referring to the ethical sense, not the biological sense, since biology doesn’t address the question at hand.