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.