Chimpanzees aren't humans, but are they similar enough to humans that they should be given some of the same legal rights as us? That's essentially the question before a New York court in a thought-provoking case that raises legal, scientific and philosophical issues.

An animal rights group called the Nonhuman Rights Project is trying to free a captive chimpanzee named Tommy using a novel and historic legal argument.

Steven Wise, lawyer and president of the Nonhuman Rights Project, argues on behalf of Tommy, a chimpanzee, before the New York Supreme Court Appellate Division on Oct. 8, 2014, in Albany, N.Y. (Mike Groll/Associated Press) For the first time in a U.S. court it was argued that a non-human animal should be recognized as a legal person. The group maintains that chimpanzees shouldn't be thought of as "things" that can be owned but as "persons" who therefore have fundamental rights — namely, the right to liberty.

The group wants Tommy declared a legal person so it can get what's called a writ of habeas corpus, which would then allow the courts to determine if a person's detention is lawful.

In other words, if Tommy were considered a person his owners would have a hard time justifying his captivity, but as long as he's a "thing," it's fine to keep him locked up. His owners say, in fact, that according to the law he has to be fenced in and is not allowed to roam around their property.

"Sometimes people think we're trying to get human rights for chimpanzees. We're not. We're trying to get chimpanzee rights for chimpanzees," Steven Wise, the group's president and an animal protection lawyer, said in an interview.

A moral and legal wrong, group argues

To get a judge to free Tommy from his cage on a private property in Gloversville, N.Y., Wise and his team argue that chimpanzees are self-determining, autonomous beings with complex cognitive abilities — just like humans. Scientific research shows they make choices, display emotions, communicate, have memory, learn, and suffer from not being able to move about freely, according to legal documents in the case.

These characteristics are sufficient evidence to recognize chimpanzees as persons and therefore declare their confinement unlawful, the group argues. It has also filed two other lawsuits on behalf of three other chimpanzees in New York State.

the New York Times Magazine profiled the Tommy lawsuit in April 2014. The case has generated a lot of media attention since it started almost one year ago. (Alex Prager for New York Times) "We think that we're looking at an egregious moral wrong, and that ought to be a legal wrong as well, and these animals should not be able to live in this way," said Wise. "It's a terrible thing. It's like putting a human being in solitary confinement for its entire life."

Wise wants Tommy sent to a sanctuary in Florida and said he's twice offered to drop the lawsuit against the chimp's owners, Patrick and Diane Lavery, if they would agree to let him go. They haven't agreed.

"He's doing well," Lavery said in a brief phone call with CBC News. She said they've had Tommy for about 10 years and got him from someone who could no longer care for him.

Lavery said they are animal lovers and take good care of Tommy. They also have 15 reindeer and other animals, she said. Lavery described the lawsuit as "ridiculous," and said, "It wouldn't be fair to Tommy or to us," if he were taken away.

His cage measures about six metres by 20 metres and it's enough room for him, Lavery said.

Wise, of course, disagrees when it comes to Tommy's living conditions. He visited the property last year. The owners were not home at the time, but someone who was there let him into the large warehouse-type structure that houses Tommy's cage.

"There was Tommy, his face pressed against the cage, watching us … he didn't move. He just looked at us. He did not look like a happy chimpanzee," said Wise. The building was too dark to see into Tommy's cage, Wise said, adding that a small TV sat outside of it facing the animal.

Case about liberty, not about animal welfare

This case isn't about how Tommy lives, however, and that's why the Nonhuman Rights Project isn't using existing animal welfare laws to try to free him. The group's point is that Tommy shouldn't be locked up in the first place.

Imagine you are kidnapped, Wise said, and you are kept in a 100-room mansion. It doesn't matter where you're being held or how well you're treated, you're still being held against your will. You have a right to be free — and so does Tommy, Wise said.

The lawsuit filed last December was rejected by a lower court, but it was appealed to a higher appellate court and a hearing was held in October. The decision could come any day.

If Wise wins, the implications will depend on how broadly the court writes its decision. Tommy most certainly would be freed and the decision would likely apply to any other chimpanzees in the state.

Beyond that the court could rule other non-human animals could be considered persons if, like chimpanzees, they are thought to be autonomous beings.

The Nonhuman Rights Project believes elephants and dolphins could also meet the test, based on the scientific evidence that is known about them. But this case won't open the floodgates and lead to all animals being treated as legal persons, Wise suggested, because as far as he knows there isn't scientific evidence to show that chickens, for example, are autonomous beings like chimpanzees.

The Nonhuman Rights Project for now is only focusing on certain animals and is preparing another lawsuit on behalf of an elephant.

Wise acknowledged that some in the legal field aren't behind him, but he said they likely haven't read through the case in detail. Autonomy is highly valued in the legal system, he said, and that's what his group is counting on for an eventual victory.