The Essential Pro Life Arguments Part I

by C. Fletcher Armstrong, PhD

Pro life arguments really rest on three simple fundamental beliefs. The first is normative, the second medical or scientific, and the third is political. First, the most basic pro life argument, that all human beings have a right to live. Second, that preborn humans are human beings (so they have a right to live). Third, that the primary purpose of government is to protect fundamental human rights.

We begin this article with the second of these pro-life arguments (that preborn humans are human beings), because in the years since Roe vs Wade was decided, this component of the pro life argument has been firmly established, beyond any reasonable objection. Scientists agree that life begins at conception, also referred to as fertilization. For example, the embryology textbook Human Embryology & Teratology, 3rd Edition, states:

Although life is a continuous process, fertilization ... is a critical landmark because, under ordinary circumstances, a new, genetically distinct human organism is formed when the chromosomes of the male and female pronuclei blend in the oocyte. [i]

This aspect of the pro life argument was further strengthened by French geneticist Jerome L. LeJeune, who asserted the following when testifying before a United States Senate Subcommittee in 1981:

To accept the fact that after fertilization has taken place a new human has come into being is no longer a matter of taste or opinion. The human nature of the human being from conception to old age is not a metaphysical contention, it is plain experimental evidence. [ii]

Even though many pro-choice advocates that we encounter on campus still assert that we don’t know when life begins, the more sophisticated pro-choice advocates have been forced to concede this pro life argument. For example, pro choice philosopher David Boonin, in his book A Defense of Abortion:

Perhaps the most straightforward relation between you and me on the one hand and every human fetus from conception onward on the other is this: All are living members of the same species, homo sapiens. A human fetus, after all, is simply a human being at a very early stage in his or her development. [iii]

Peter Singer, Professor of Bio-Ethics at Princeton University, concurs:

... there is no doubt that from the first moments of its existence an embryo conceived from human sperm and eggs is a human being ... [iv]

They don’t concede this point vigorously, because it is politically useful for most Americans to be confused about the humanity of the preborn. But in formal settings, they have been forced to abandon the “not a human” argument and move on to something else: the proposition that some human beings have a fundamental right to life and others do not. Hence the debate has morphed from the question of when human life begins (a question of medical science) to a question of when human personhood should granted (a question of philosophy and politics). In a democratic republic, the voting citizens decide who gets rights and who does not, and we define (or manufacture) the criteria we will use to justify our decision.

Pro choice advocates disagree about the qualities that ought to qualify certain ones of us to receive rights of personhood. Some say the ability to feel pain. Others prefer viability, which they define as the ability to remain alive outside the womb. Members of the general public may point to more definable characteristics such as the onset of the heartbeat or the onset of brain-wave activity (not realizing that these characteristics appear early in the first trimester).

Pro choice advocates often cite qualities that are hard to define and quantify, such as “self-awareness.” This is very convenient, for several reasons. First, there is no scale of units by which self-awareness can be quantified. Second, even if there were “self-awareness units,” there is no established number of them that qualifies one of us for personhood. Finally, even if we postulated such units, there is no measurement technique that would tell us if the required number of self-awareness units had been attained. Pro choice advocates are thus able to maintain the status quo by focusing attention on questions that can never be answered. In other words, since we can’t know when a child is sufficiently self-aware, it should be legal to kill him before birth.

The main problem with this argument is that it avoids the question of whether we may assume that a born person (e.g., a newborn baby) is sufficiently developed to deserve rights of personhood. In other words, who can say whether a newborn is sufficiently “self-aware” to protect him from homicidal parents?

Problems with this argument have influenced other pro-choice advocates to concede the right to life for all human beings, but then to assert that the rights of the preborn human are superceded by the rights of the mother. We will address this argument in Part II.


  1. Ronan O'Rahilly and Fabiola Muller, Human Embryology & Teratology, 3rd ed. (New York: Wiley-Liss, 2001), p. 8.
  2. Francis Beckwith, Politically Correct Death: Answering Arguments for Abortion Rights (Michigan: Baker Books, 1993) 42.
  3. David Boonin, A Defense of Abortion (Cambridge University Press: New York), p. 20.
  4. Peter Singer, Practical Ethics, 2nd ed. (Cambridge: Cambridge University Press, 1993), p. 85-86.

Fletcher Armstrong, PhD
Southeast Director
Center for Bio-Ethical Reform