What is the difference between a human and a person?
That question emerged in a conversation about abortion that, as long exchanges often do, traveled down several different paths. Biology gives us a pretty clear definition of "human," aka Homo Sapiens. Internet search results (many of which presume one context or another) aside, we have biological taxonomy, with "species" at its most granular level, to show us how to interpret the H word.
"Person," on the other hand, is a bit more complicated. Personhood is a concept that advances certain qualities, or "rights," if you prefer, that are recognized by whatever social structure that human functions within. Or, less abstractly, governments are formed to protect persons' rights.
Throughout most of human history, such protections weren't conveyed equally to all humans, and some got none at all. Slaves and serfs and low caste people did not have the same rights as freemen and nobility. Kings had more rights than nobles, nobles had more rights than commoners, commoners had more rights than serfs, serfs had more rights than slaves.
In other words, for thousands of years, slaves, despite being human, weren't persons, they were property. This was true across just about every society in history, with no regard for skin color, ethnicity, religious belief or lack thereof, geographical location, or any other discriminator. Humans have enslaved humans for most of human history.
It is only in the last few hundred years, thanks to the (secular) minds of the Enlightenment, that we've advanced the premise that every human is a person whose rights government is obligated to enshrine and protect.
Personhood, therefore, is a social construct, not a biological classification.
As it turns out, societies that grant it to everyone work better than all the other forms, past and present, that have ever been tried. Living standards have advanced more in the couple hundred years since the Enlightenment, in the societies that clove to its tenets, then in the six thousand years of structured societies that preceded it. The concepts that we are all equal, that owning another human being is wrong, that accident of birth should convey neither inherent power over others nor permanent subordination to others, and that logic, rationality and method are a better path for human success than subjugation to mystical authority have proven themselves as better for the human species as a whole than anything that emerged before or since.
To repeat, it was rational and fearless thought that concluded that all humans are persons.
This, at least for me, hollows out any religion-based argument regarding abortion. None of the major religions demanded that all humans be treated as persons. Quite the opposite - all the big ones codified slavery, and war against those not of the faith, and other actions against non-persons. Sanctity-of-life arguments collapse when their foundations include affirmative disregard for the lives, rights, and well-being of non-persons, and it's why I concluded that the abortion debate boils down to this: "When does a fertilized egg become a person? When does personhood start?" I wrote about this at length recently (spoiler alert - it's a metaphysical rabbit hole).
Before we can debate its beginning, though, we should come to terms with its applicability. Personhood is a critical concept in the matter of societal organization and the moral guardrails that go along with such organization. Societies exist today that do not convey personhood upon all their members, and we see what the governments that run those societies do to their non-persons. Uighurs, Tibetans, and others who reside within China's declared borders and are subject to the governing Chinese Communist Party are not granted the same degree of personhood as according-to-Hoyle Chinese citizens are. The genocides in Darfur, Rwanda, Bosnia, and on and on and on were abrogations of personhood by governments. All those killed were humans, but they were not persons as far as those who headed those governments were concerned. Islamist societies do not grant full personhood to their women, and deny it entirely to gays. I need not mention the Holocaust here, I assume.
What we take for granted in today’s Western societies is a historical anomaly. A very good one, but an anomaly nonetheless. There are countless people around us today that would deny us a degree of our personhood, as they quest to abrogate our liberties and the protections for them written into our governing documents, and there are societies around the globe even today where citizens are not granted equal protections (or any at all in some cases). Eternal vigilance is indeed the price of liberty.
“I am not a number! I am a free man!” - Number 6, The Prisoner
https://youtu.be/dWTdmwwK-ME