I'd like to ask a purely logical question (with no regards to personal "opinion" or religion) about the interpretation of science on the matter of abortion in the situation of a decision being made purely based on the philosophical concept of intelligent life being valuable. Hopefully I can relay this question in a manner strictly proper for this site.

In a situation where the "decision maker" (whether that be a human or a judicial system) strictly subscribes to the following principles:

  • human life is valuable, worthy of protection

  • one human life is not more valuable than another

  • decisions should be made based on applicable science

  • science tell us "A human fetus is both alive and human"

Must the decision maker decide that human abortion is wrong, based on the subscribed principles? Are there arguments that would alter this decision, with these principles strictly involved in the decision making?

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    It is worth noting that most of the disagreement about the abortion issue arises from different meanings of "human" in the different premises. On the face of it, each premise seems reasonable, but it's because we use different context to interpret each premise. If you insist that all uses of "human" be in exactly the same sense, the premises are highly controversial themselves. Roughly, the distinction is between "this entity is alive, and is Homo sapiens" and "this entity is a person".
    – Rex Kerr
    Commented Jul 10, 2015 at 18:03
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    <x> is clearly human. <x> is clearly alive. Is it wrong to kill it? <x> = red & white blood cells, routinely killed by labs working on blood samples. Commented Jul 11, 2015 at 0:50
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    There is a subtle difference between "is alive and is human" and "is a human life". Your arm is, independently of the rest of your body (though not for long if made independent of your body) alive and human.
    – Random832
    Commented Jul 11, 2015 at 2:53
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    I believe many (most?) legal systems do not subscribe to your second principle. Commented Jul 11, 2015 at 5:43
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    @11684 Look at the compensation (not the punitive damages) awarded by courts for death. Also compare attitudes to deaths of civilians in war zones when they are your nationals compared to others... Commented Jul 11, 2015 at 14:18

5 Answers 5


All personal opinions aside:

Accepting these principles as given would argue fairly unambiguously against abortion in most situations. However, they do not necessitate a blanket judgment of "abortion is wrong," given that they do not offer guidance for the situation where more than one life is at stake. The most likely and familiar case is where the pregnancy threatens the life of the mother, but other scenarios could be created as well.

The outlined scenario also leaves the door open for the possibility that other values --quality of life, for example --could override these values. You would need to make it more clear that protection of human life is a prime or overriding value to preclude this.


With regard to this assertion:

science tell us "A human fetus is both alive and human"

While the above true, it does not necessary follow that a fetus is a human life.

There are other entities that are both alive and human that are not human lives. For example, my thumb is alive, and it is human. But it in and of itself does not constitute what we call a human life. It's a thumb.

To conflate "alive and human" and "human life" is to engage in equivocation, which is one of many logical fallacies.

Ergo the decision maker must not necessarily decide that abortion is wrong given these principles, since the key logical underpinning that would drive that conclusion is in fact fallacious.

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    Your thumb is not alive. You are alive and your thumb participates in your life. A fetus is a distinct life in a way a thumb is not. This is mere science.
    – virmaior
    Commented Jul 11, 2015 at 0:42
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    Blood cells clearly are alive. Sperm is clearly alive. Eggs are clearly alive. All are human. Commented Jul 11, 2015 at 0:51
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    @LorenPechtel that was a very poorly considered thought. Come ON. They are human in the sense that they are human components but we are talking about human in the noun form, human(s) - noun. not human <insert body component here> - adjective A human sperm is not a human, that's clearly completely different.
    – J.Todd
    Commented Jul 11, 2015 at 2:29
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    @MediaWebDev You are making the logical fallacy he's pointing out here. Commented Jul 11, 2015 at 3:47
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    With all due respect, "X participates in life" is word salad without any scientific meaning, and of no relevance to the original post. The point the OP will need to prove is that the phrase "is both alive and human" is equivalent to "is a human life," or that the meaning of the phrase "alive and human" is equivalent to the intended meaning of the word "life" in the sentence "human life is valuable." OP is welcome to edit the original post and add either of these as an another bullet item. Until then, I stand by my answer. My thumb, while valuable, is not as valuable as a human life.
    – John Wu
    Commented Jul 11, 2015 at 4:45

Premise 1 doesn't protect against other interests being more valuable than that of human life (and it's structure seems to imply that a utilitarian type of approach is warranted). Thus, without further elaboration, accepting these premises does not commit one to a decision that abortion is universally wrong.


You wrote,

a decision being made purely based on the philosophical concept of intelligent life being valuable

I guess therefore that the premise of your question is an implied syllogism, i.e.:

  1. Intelligent life is valuable.
  2. Human life is intelligent.
  3. Therefore Human life is valuable.

If so, that seems to me to contradict the following subsequent statement in the argument:

  • science tell us "A human fetus is both alive and human"

    Perhaps a human fetus isn't "intelligent life" (at least not until later in life – for example in early life I think that the brain exists but hasn't been hooked up yet, and therefore it must fail most definitions of "intelligent" I could think of).

    I say "contradict" because, if you're saying that "a human being is valuable because it's intelligent", then given that a (sufficiently young) fetus is not "intelligent", you might then have to grant that a fetus is not human (if being "intelligent" is a necessary attribute of being human).

Or, if you kept the "a fetus is a human" definition, then the argument might break at this statement:

  • one human life is not more valuable than another

    If one human is intelligent (because it's a living adult) and another is not (because it's a young fetus which hasn't yet developed a nervous system), and if human life is valuable because it's intelligent, therefore one would be more valuable than another.

I suspect that there's a problem caused by using an adjective as a noun. The word "human" can be used as an adjective or a noun. It can be used as an adjective, e.g.:

  • Human being
  • Human fetus
  • Human fingernail
  • Human gamete

These take the same adjective but are not the same "things". Your adding the noun "life" in your statements lets you say, "A and B are both human life, C and D are not human life", which lets you equate A and B. But notwithstanding your equation they're still not the same thing.

I suspect that "a fetus is a human being" implies some type of reification.

Statements like "all human lives are equal valuable and equally protected" is only more-or-less true, and in limited/specific circumstances. For example people are naturally inclined to protect their family and friends more than they protect strangers and enemies. And for example the national law (in many though not all countries) is more inclined to protect post-birth independent human life more than pre-birth non-independent human life.

  • @virmaior Thanks for your comments. I edited my answer: is it clearer now?
    – ChrisW
    Commented Jul 11, 2015 at 10:38
  • Yes, this makes it much clearer as to where you think the problems are.
    – virmaior
    Commented Jul 11, 2015 at 10:40

Even leaving semantics out of this question, the way you have "built" the question, leaves only one possible answer. Yes, a decision maker that subscribes to the stipulated principles, would decide against human abortion, (which is not really a decision, since there is no choice)!

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