History is replete with instances where the definition of personhood has had life-or-death consequences for entire groups.
(LifeSiteNews) — With the overturning of Roe v Wade, states have been wrestling with the issue of abortion with new vigor. At the center of the argument is the idea of the human person. What it means to be a person determines not only if abortion is legal but also the ethics of procedures like IVF and experimentation with embryos. The state of Nevada, with the goal of protecting the IVF industry from any prenatal definition, stated unequivocally in Bill 217 that “Any fertilized human egg or human embryo that exists in any form before implantation in the uterus of a human body is not an unborn child, a minor child, a person, a natural person or any other term that connotes a human being for any purpose under the law” (Sec 10 line 22 – 29)
As I was reading this document, I was looking for a positive definition of what it means to be a person. It’s not enough to say that an embryo is not a person, as defining what a person is allows an observer to identify what is not a person. Yet in fact the document at no point defines what a person is. This is the crux of the problem: there is no definition of “person.” I hope to show in this article that it is logically impossible to say that a biological entity such as an embryo is not a person if the word “person” is not clearly defined. This type of argument is a logical fallacy which negates something without a proper definition. A colloquial example will make this clear.
Let’s imagine the following dialogue to clearly understand the fallacy. You are walking with your buddy who is a botanist. You see a beautiful flower. The botanist says it’s a beautiful flower, but it’s not a snorkleflower. You respond, “Oh I have never heard of a snorkleflower. What does a snorkelflower look like?” The botanist responds, “I don’t know what a snorkleflower looks like (undefined), nor do I know what color they are. However, I know this is not a snorkleflower and, therefore, since it’s not a snorkleflower, we can cut it down. It’s not an endangered plant for sure.” I can imagine you would look at him with disbelief and say, “You mean, you don’t know what a snorkleflower is, and yet you say this is not one? How can you say that unless you have defined and explained what a snorkleflower is to me? It doesn’t make sense.”
As a teacher of Logic of Knowledge, I am familiar with the logical fallacies that have been identified and passed down to us from Aristotle. Now I knew the state of Nevada’s refusal to acknowledge personhood in early human life sounded like a fallacy, but the closest one that I could think of was Argument from Ignorance. In this case we argue for the existence of something because we are ignorant of evidence. For example, some say that aliens built the pyramids. The argument is that if we can’t explain how they were built, nor can we duplicate them today with our present technology, then they must have been built by aliens who had such technology. In this case the ignorance of evidence is the reason for the conclusion. However, this is not sound logic because the construction of the pyramids could have been a lost civilization of humans, or the knowledge of construction methods could have been lost through time. The ignorance of evidence does not guarantee the conclusion. There must be evidence to establish the conclusion, and ignorance is not evidence.
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In the case of personhood, legislatures are not claiming ignorance of evidence, they are claiming ignorance of a definition. They are attempting to say that an embryo is not a person without giving a clear definition of what a person is.
At this point I had exhausted my analysis, so I brought it to the attention of Artificial Intelligence. AI has an uncanny ability to be logically sound so perhaps it could offer some insight on the issue. AI actually agreed with me that the closest fallacy is the argument from ignorance. It also agreed that it was a fallacy: you had just to substitute “definition” with “ignorance.” AI even gave a name to this fallacy, calling it the Fallacy of the Undefined Denial or “Negatio sine definition”. Finally, AI stated that unless you define a category, the negative statement of what something is not, is semantically empty, that is, it has no meaning. See AI’s explanation below:
Suppose someone points to an unfamiliar food item and confidently declares, “That’s not a hot dog.” When asked what a hot dog is, they respond, “I don’t know — and I won’t define it.” This statement commits a logical error: it attempts to deny that something belongs to a category without having — or providing — any definition of that category. Without at least a working definition of what a "hot dog" is, the claim “This is not a hot dog” is semantically empty. One cannot meaningfully exclude something from a set if the boundaries of that set are unknown or undefined.
This error may appear similar to the argument from ignorance (argumentum ad ignorantiam), which occurs when a claim is accepted as true or false based on a lack of evidence to the contrary. However, in this case, the problem is not merely an absence of evidence — it is an absence of definition. The person is not saying, “I’ve seen no evidence it’s a hot dog”; they are saying, “I don’t even know (or refuse to say) what a hot dog is, yet I know this isn’t one.” The fallacy, therefore, is more fundamental: it undermines the possibility of logical classification altogether.
We may call this error the Fallacy of Undefined Denial, or in Latin, Negatio sine definitione — denial without definition. It is a failure to ground a negative assertion in any meaningful conceptual framework, and thus it renders the statement logically void. (ChatGPT May 14, 2025)
There you have it: Negatio sine definitione. Denial without definition: AI’s contribution to the world of philosophy.
This is what the state legislatures are doing when they engage in this type of lawfare. They never give a positive definition of the person. They simply state that the embryo is not a person, and therefore it also does not have the rights of a person. Yet since we have no definition of what a person is, then logically we can’t say if an embryo is or isn’t a person.
I think pro-life lawyers, politicians and activists in this field need to push for a positive definition of a person at every turn and in every manner. Perhaps they should even offer legislation giving a definition. They should bring this point out by saying that an embryo is not a person is a logical fallacy since the word “person” is not clearly defined. You can’t say what something is not if you can’t define what it is. Then you can give any example which follows the model given above.
Courts and judges will be reluctant to engage in the positive definition of a person since this debate will become very sticky fast. This definition must include all people at all stages. If I define a person as someone who can speak and talk, then a person who can’t speak or talk is not a person. This is just a small example, but this definition must be made if as a society we wish to be logically correct and respectful of all human life.
Defining what a person is will not be easy due to the consequences of such a definition. However, the debate has not even begun; it is simply avoided at all costs. I took up the challenge myself and wrote an article on defining the idea of personhood. My definition is certainly up for debate, but let the debate begin. Read it here.
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History is replete with instances where the definition of personhood has had life-or-death consequences for entire groups. Historically speaking, many groups have been marginalized and even terminated because they were not considered to have personhood. This latest attack on human life is the most subtle by far; however, the mechanics of how human life is discarded are the same. The first step is to say we are not dealing with human beings; embryos are even called property, as were slaves in times past.
Africans during the slave trade were considered less than human; natives in the Americas were considered soulless savages by many, and women have been considered second class citizens with few rights. The mentally handicapped were considered nonpersons for the longest time. Then there’s the plight of the Dalit in India. In all cases these groups were not defined as complete humans and did not deserve all human rights.
It’s time to end this cycle by coming up with a sound definition of the human person. Let the debate begin, and it must start where it will have a meaningful impact in the state legislatures and in the courts. Avoidance and refusal are no longer an option.
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George Matwijec is an adjunct philosophy teacher at Immaculata University who specializes in teaching knowledge and logic He is the author of a book entitled “My Interview with AI”. He can be reached at iteacher101.com
