The Rational Nature Argument for Equal Treatment

The change we’ve made to the way we argue for equal treatment for the unborn, and why we made it.

Estimated reading time: 4 minutes.

It’s been almost a year since I started this blog and by far my most popular post is my explanation of the basic Equal Rights Argument that I and my colleagues at Justice For All have been using in conversations with pro-choice people. It became so effective that I called it the “most undervalued argument in the pro-life movement.”

We’re arguing that if adult humans deserve equal treatment, that must be because they all have something in common, and it must be a property that they all have equally. We try to figure out what that property is that seems to be grounding equal treatment, and then ask whether the unborn also has that property equally. If they do, then the unborn deserve equal treatment.

What is the property that human adults have equally? Originally, we were saying that it seems like we all have “humanness” in common. If someone asks why “humanness” matters, I would say something like, “I believe there’s this guy who walked out of his own tomb 2,000 years ago. He believed in the Torah, which says that God made humans in His own image, that He did something special with humans that He didn’t do with other animals, giving me a reason to believe that ‘humanness’ might morally matter.”

But as I’ve used this argument lately, I’ve noticed there’s a pragmatic problem: it’s not terribly convincing to pro-choice atheists who immediately brush off the argument as inherently religious. That’s a practical problem, but I think there’s an even greater problem philosophically: the “humanness” argument can’t account for the right to life of fictional aliens.

Remember that scene in Men in Black where Tommy Lee Jones is hilariously interrogating Frank?


What if Tommy Lee Jones got really mad because he wasn’t getting the information he wanted from Frank, so he pulled out his gun and killed him right there? Most of us would think that was morally wrong.


It’s not because Frank is human. If Frank has a prima facie right to be equal treatment, it must be because of a property he has that is not humanness.

Disclaimer: I don’t personally believe aliens exist, although they might. That’s not the point. When we imagine sentient aliens like those in Men in Black and District 9, we think they have a prima facie right to equal treatment. Obviously we could kill aliens in self-defense, but that’s true of human persons too. I’m arguing that all humans are persons, but that there could be non-human persons. At the very least, angels seem to be examples of non-human persons.

This problem, what many philosophers call “the Vulcan problem,” is the main reason that I’m not primarily arguing for equal treatment because of humanness anymore. I do sometimes when I can tell that a simpler answer would be more helpful to the person I’m talking to, because I still believe that humanness is morally relevant, but admittedly that’s because I’m a Christian who believes that humanness really does matter.

Instead, I prefer to argue that the property we all have in common that grounds our right to equal treatment is our rational nature.

This is hardly an original argument. Dr. Frank Beckwith has done great work on this as has other important pro-life philosophers. The way I talk about it I largely owe to my friend Trent Horn, although I’m still playing with the ideas. I just want to let you in on what I’m using right now.

Let me start by putting the Rational Nature Argument as I use it into a syllogism, for clarity.

P1: A person is a being that belongs to a rational kind. (i.e. the kind with the intrinsic capacity to develop rational function.)
P2: All human organisms belong to a rational kind.
P3: The unborn are human organisms.
P4: It is prima facie wrong to kill persons.
C: Therefore abortion is prima facie morally wrong.

A few definitions:

  • Person: A person is a rational substance, a being who maintains their identity through change and has a nature that orients itself toward a rational function.
  • Rational: Self-identity, comprehending reasons for actions, choosing to act, validly inferring reasons for acting and making moral choices accordingly.

We want to argue that what matters is not your present abilities, but the kind of being you are, that will lead you to develop certain abilities, thus deserving of respect.

ethicsofabortionI think a few quotes from Christopher Kaczor’s magnificent book, “The Ethics of Abortion” would help here. This is from his section on Endowment vs Performance accounts of human value. (Most pro-life apologists use the terms “Intrinsic vs. Instrumental value,” but they mean the same thing.)

“The endowment account holds that each human being has inherent, moral worth simply by virtue of the kind of being it is. By endowment, I mean that the being in question has an intrinsic, dynamic orientation towards self-expressive activity. Beings with endowments that orient them towards moral values, such as rationality, autonomy, and respect, merit inclusion as members of the moral community.”

“Rational endowment is nothing other than the capacity, ability, or disposition (though perhaps not realizable) enjoyed only by whole, living beings whose active self-development is aimed towards and whose flourishing consists in freedom and rationality.”

Notice that this argument doesn’t require an entity to have a present capacity for rationality, nor does it require the entity needing to have crossed over a threshold of having rationality for the first time in the past. We are arguing that what matters is being the kind of being that has a rational nature.

Unborn human organisms have that nature from their earliest stage of development. And if having a rational nature is the property that grounds our right to equal treatment, then the unborn deserve to be treated equally.



The post “The Rational Nature Argument for Equal Treatment” originally appeared at JoshBrahm.comClick here to subscribe via email and get exclusive access to a FREE MP3 of Josh Brahm’s speech, “Nine Faulty Pro-Life Arguments and Tactics.”

Question: What do you think of this argument? Do you think it would be more helpful than arguing for equal treatment based on humanness? Is there a third choice you prefer?

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Josh Brahm is the President of Equal Rights Institute, an organization that trains pro-life advocates to think clearly, reason honestly and argue persuasively.

Josh has worked in the pro-life movement since he was 18. A sought-after speaker, Josh has spoken for more than 23,000 people in six countries and in 22 of the 50 states.

Josh’s primary passion is helping pro-life people to be more persuasive when they communicate with pro-choice people. That means ditching faulty rhetoric and tactics and embracing arguments that hold up under philosophical scrutiny.

He has publicly debated leaders from Planned Parenthood, the National Abortion Rights Action League (NARAL), Georgians for Choice, and one of the leading abortion facilities in Atlanta.

Josh also wants to bring relational apologetics to the pro-life movement. “Some pro-choice people will not change their mind after one conversation on a college campus. Some of them will only change their mind after dozens of conversations with a person they trust in the context of friendship.”

Josh is formerly the host of a globally-heard podcast turned radio/TV show, Life Report. He now hosts the Equipped for Life Podcast. He’s also written dozens of articles for and the ERI blog.

He directed the first 40 Days for Life campaign in Fresno, resulting in up to 60 lives saved.

Josh has been happily married to his wife, Hannah, for 15 years. They have three sons, Noah, William, and Eli. They live in Charlotte, North Carolina.

David Bereit, the National Director of 40 Days for Life, sums up Josh’s expertise this way: “Josh Brahm is one of the brightest, most articulate, and innovative people in the pro-life movement. His cutting-edge work is helping people think more clearly, communicate more effectively, and — most importantly — be better ambassadors for Christ. I wholeheartedly endorse Josh’s work, and I encourage you to join me in following Josh and getting involved in his work today!”

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