Burning off the dross

BioSLED – best argument against abortion-choice

This is the best rational argument against abortion I’ve found to date. Every counter-argument comes right back to these same human rights issues, and is thus refutable.

Everyone concedes abortion kills something. The crucial question is “what is killed?”

If the unborn are not human, no justification for elective abortion is necessary. But if the unborn are human, no justification for elective abortion is adequate. (Koukl, Precious Unborn Human Persons, p. 7)

Morally, it’s wrong to kill innocent human beings.


We base that morality on three factors:

  1. Intrinsic value of human beings – an intangible quality.
  2. Common nature of human flesh and blood – biological evidence of Law of Biogenesis, uniqueness of DNA & embryological/anatomical science.
  3. The equality of common physical attributes of human beings - Size, Level of Development, Environment, and Degree of Dependency (SLED). 

If we do not morally discriminate against human beings outside the womb with these attributes (we treat them equally as humans under the law) then such conclusions also apply to pre-born human beings because:

  • Size - Hillary Clinton is not less human than Shaquille O’Neal. An embryo is not less human than a newborn.
  • Level of Development – Toddlers are less developed than pre-adolescents who are less developed than adults. An embryo is the organ development stage of a human being while in the next stage, a fetus’s organs mature, just as an adolescent’s organs mature through puberty.  
  • Environment – Astronauts and scuba divers do not lose their human nature in non-supportive environments.  A womb is the natural environment for the pre-born at their level of development. Exposing human beings to unnatural, uninhabitable environments is an act of murder.
  • Dependency – We don’t kill those who depend upon us. Infants depend upon parents/guardians for all their primary needs. Our dependencies extend to each other, and without the defense of the goodness of meeting human dependencies, none of us would be alive.

Discussing pro-life views shouldn’t be a monologue. Provide your reasoning, but also ask others questions to bring them into conversation. Seek points you agree on; ask why they are important. Establish common ground before refuting objections. Your response will then be appropriate.

Here’s how to refute two very common objections to BioSLED: 1) Non-Personhood and 2) Mother’s Rights.

  1. Refuting Non-Personhood Arguments – such arguments deny the intrinsic quality of human beings by falsely assuming (petitio principii) two components (body and person), instead of one. These are a play on Level of Development. Gently ask: “Would you be willing to undergo the same destruction of your body that is performed on the unborn during an abortion, and if not – why?” They can’t prove their own personhood without referring to their own physical body, so gently question them until they do. We know scientifically from the moment of conception the pre-born also has a human body. We can’t establish tests for denying the rights of pre-born human beings that we, who also have human flesh and blood, are unwilling to take – that’s discrimination. Refuting this works best in-person, not over the Internet.
  2. Refuting Bodily Autonomy Arguments (aka Mother’s Rights) – some argue gestation is a special right granted by the mother. This goes back to Dependency. We don’t kill those who are dependent upon us. Some argue biological dependency is different, but this falsely assumes (petitio principii) the responsibility to be humane can have exceptions because an innocent human being is undeniably killed. Further, such killing is an act of commission, meaning the violence of abortion is a direct appeal to force (argumentum ad baculum) on the mother’s behalf. Specifically, force is appealed to based on the victim’s Environment – the natural location in the womb of the child’s mother. We wouldn’t want anyone we were dependent upon to justify killing us because we existed in an environment they claimed.

Although BioSLED is an exceptionally strong argument against abortion, it needs to be conveyed gracefully, and the best way to do that is in person in a non-threatening way. Those who defend abortion usually do so for very personal reasons. So no matter how logical, the heart has to change.

This argument is like a very sharp Japanese Samurai sword – it is not meant to be handled without great discipline, respect or care for the other person. Use it only in love.

If you find this valuable – please link to it. If you think it needs improvement – let me know in the comments. Thanks!

This argument is based on the work of Scott Klusendorf of Life Training Institute, Greg Koukl of Stand to Reason, Francis Beckwith’s Defending Life and the SLED acronym came from Stephen Schwarz who wrote The Moral Question of Abortion.


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  6. In general, I tend to agree with your argument. However, you don’t address the fact that the majority of abortion candidates are uneducated and poor, and if these children were to be born, then they would be impoverished, likely grow up to continue the cycle of generational poverty, and to commit crimes. By advocating criminalizing abortion in the US, then, one would be endorsing increasing the violent crime rate, the illiteracy rate, and the poverty rate in the US. Is that an acceptable trade-off? Perhaps one in a million of these unborn children would accomplish great things (assuming an even distribution of success)… Ayn Rand says only about one in three-hundred people (about 3z) matter. So, 299/300 of these aborted children don’t matter? And that’s assuming that these infants have the same chance as born infants to matter… in fact, these children are LEAST likely of all to have exceptional lives. When your entire argument and political stance is based on exceptional, unusual cases and not likelihoods, few thinking people are interested in buying into your arguments. Yours is an entirely emotional, not rational, argument.

    The way to minimize the number of abortions performed is to minimize the number of unintended pregnancies. Where does your group stand on contraception, birth control and sex education?

  7. Nik said :
    In general, I tend to agree with your argument. However, you don’t address the fact that the majority of abortion candidates are uneducated and poor,… one would be endorsing increasing the violent crime rate, the illiteracy rate, and the poverty rate in the US. Is that an acceptable trade-off?

    Your question (counter-argument, really) implies 1) that humans are only functionally valuable, not immeasurably valuable; and 2) people can’t change when they face adverse conditions.

    That’s a very depressing perspective. Simple question: do you love people for who they are, or for what they do for you? Would you tell someone you “loved” they were only functional to you?

    Further, your justification (via Ayn Rand) based on human exceptionalism only works if you are exceptional. Do you realize you live entirely at the mercy of others upholding their responsibility not to kill you? Seriously. Laws on paper are only good to the point where people believe there is a morality behind them. And last time I checked murder continues. Shall we talk about that likelihood?

    You contend my argument is based on emotion, while yours isn’t. However, at the very core of your argument is a pure hypocrisy:

    you condone violence to avert violence;
    deadly force is merciful and morally justifiable against innocent human beings;
    killing our own children is an act of responsibility to others;
    and, ultimately the violence of abortion is an appeal to force to remove the assertion (truth) of the child.

    Sorry, that’s not rational, it’s insane. So your logic is invalid and your charge false. Nik – your comment looks fearful, very typical of pro-choice “population-control” arguments – “get them before they get us.”

    Nik said :The way to minimize the number of abortions performed is to minimize the number of unintended pregnancies. Where does your group stand on contraception, birth control and sex education?

    Group, what group? My family and I believe in the sanctity of marriage, the blessing of chilldren, that sex is a family matter, not a public one and that sex education should be frank discussions between parents and their children, not for the public to impose upon our family.

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  9. Interesting and persuasive arguments.

    I think, though, that in the refutation of non-personhood arguments, you mean ‘undergo’ and not ‘forgo.’ Most people, I imagine, would be quite willing to forgo that kind of destruction!

  10. Your argument is a very good one. However, I think it is fairly obvious that there is a separation between the human body and the person. It’s because a human body contains a human person that it is intrinsically valuable, versus a dead body which is just a lump of cells. It’s not DNA that gives us worth as a person,it’s the soul (for lack of a non-religious term) which makes us who we are. I can prove my personhood without having to show a body with an independent set of DNA. Take for example, the concept of rational thought. There is nothing in our biological system which accounts for our ability to understand the images and sounds that our senses put in our brain. There is no biological explanation for the ability of humans to disobey animal instinct. In both these situations, there is clearly an “other” who understands what his/her eyes see and decides to do his/her own will instead of what instinct says to do. This makes the argument against abortion even stronger, because it doesn’t just violate the rights of a biological human, but the rights of a human person. The fetus is, for all we know, a complete human person without a complete body. Like an artist with a damaged instrument. This is why any attempt to assign personhood at an arbitrary time after conception fails.Since we don’t know when the human body receives the human person, it is better to err on the side of caution and make abortion illegal than risk violating another person’s right to life, whether their body is capable of sensing the abuse or not.

  11. Hi David – thanks for your comments. Although we both believe abortion should be illegal, we have different views regarding what constitutes human personhood, and whether that is additive or intrinsic.

    I believe the human person is an intrinsic whole: a person’s spirit is inseparable from their body. This whole constitutes the entirety of their person. I have sound Biblical reasons for believing this to be the case. I believe a person has a spirit, but this is intrinsic – not additive. It doesn’t come and go, nor is it detachable as we think of as parts/pieces relationships.

    Whatever our views regarding personhood, we must not forget that it is a human body which is destroyed during abortion. My simple test for proof of personhood is to be subjected to the same destruction which is done to the unborn, and then once destroyed, to prove your person was completely unaffected. Such proof would require supernatural communication, because your natural life would cease to exist!

    The danger in arguing personhood as an additive and not intrinsic nature of being is that doing so leaves too much philosophical wiggle room. Peter Singer makes such arguments. I contend if he doesn’t know when he became a person, then it would be impossible for him to claim any development of the body he inhabits as being “his development”. Further, how could he claim the body he inhabits as “his” – how would we proscribe ownership/title to that body? It’s illogical.

    Our bodies are grounded in flesh at conception, and whatever the spiritual outgrowth of that momentous event is immaterial to the physical destructive procedure of abortion. Arguments purely in the spiritual realm are outside our jurisdiction!

    You may wish to study the materials at