The Patent Act requires an “inventor” to be a natural person, the US Court of Appeals for the Federal Circuit said, rejecting computer scientist Stephen Thaler’s bid for patents on two inventions he said his DABUS system created.

Thaler said in an email Friday that DABUS, which stands for “Device for the Autonomous Bootstrapping of Unified Sentience,” is “natural and sentient.”

His attorney Ryan Abbott of Brown Neri Smith & Khan said the decision “ignores the purpose of the Patent Act” and has “real negative social consequences.” He said they plan to appeal.

The US Patent and Trademark Office declined to comment on the decision.

Thaler has undertaken a global effort to win patents for DABUS. He has lost other bids for patents that name DABUS as their inventor in the European Union and Australia.

The PTO and a Virginia court both rejected two Thaler applications for DABUS patents, covering a beverage holder and a light beacon, because the system is not a human being.

Thaler challenged the Virginia decision before the Federal Circuit, which hears patent appeals. Abbott told the Federal Circuit during an oral argument in June that the ruling was “at odds with the plain language and purpose of the Patent Act,” which is meant to promote innovation and does not specify that an inventor must be a natural person.

But “there is no ambiguity: the Patent Act requires that inventors must be natural persons; that is, human beings,” Circuit Judge Leonard Stark wrote Friday for a unanimous three-judge panel.

Stark said the Patent Act requires inventors to be “individuals.” He said that “individual” means a human being, citing the word’s ordinary use and how it used in the Patent Act.

“For instance, the Act uses personal pronouns – ‘himself’ and ‘herself’ – to refer to an ‘individual,” Stark said. “It does not also use ‘itself,’ which it would have done if Congress intended to permit non-human inventors.”

Thaler’s argument that awarding patents to AI systems would encourage innovation was “speculative,” Stark said. He also dismissed Thaler’s concerns that denying AI patents would undermine the purpose of patents outlined in the US Constitution to “promote the progress of science and the useful arts.”

The case is Thaler v. Vidal, US Court of Appeals for the Federal Circuit, No. 21-2347.

For Thaler: Ryan Abbott of Brown Neri Smith & Khan

For the PTO: Dennis Barghaan of the US Attorney’s Office for the Eastern District of Virginia