“If we ever encounter an alien race, they sure won’t be humans, but they’ll probably be persons. Is a human clone a person?”
Corporations began to be granted personhood, along with property rights, in the 14th Century. And the word took on a different meaning when, in 1824, the British Vagrancy Act declared that “Every Person wilfully, openly, lewdly and obscenely exposing his Person … with intent to insult any Female, shall be deemed a Rogue and Vagabond.”
Women were still fighting for full personhood in the 1970s:
During the height of the feminist movement, women used it to claim a better role in society, as seen in this 1970 usage in the OED: “Women are at last becoming persons first and wives second.”
Could an artificial intelligence could be considered a person? What about nonhuman animals? PETA recently filed a lawsuit claiming that SeaWorld is violating the 13th Amendment by keeping orcas as slaves.
The PETA case is unlikely to go anywhere since the judge will likely rule that orcas don’t have legal capacity to sue. But a much more serious and plausible legal case is being prepared by the Nonhuman Rights Project. Theirs may be the first to breach the legal wall that says only humans (and their corporations) can be considered as persons.