Appeal Filed : 
Thaler Challenges Refusal to Recognize AI as an Inventor on a Patent—Implications Beyond Inventorship

In an ongoing saga playing out in Canada and in courts around the world, Stephen Thaler has appealed to the Federal Court of Canada an underlying decision that refused to acknowledge an artificial intelligence (AI) system as an inventor. In the December 5, 2025 Notice of Appeal,¹ Mr. Thaler challenges a decision of the Commissioner of Patents refusing a Canadian patent application on the basis that the listed inventor was an artificial intelligence system, and not a human.

Mr. Thaler’s application seeking to recognize an AI system as an inventor has been rejected in nearly every other jurisdiction around the world, including by the U.K. Supreme Court² and the U.S. Court of Appeals.³

Significantly, the Thaler appeal may have consequences that extend beyond this single patent application. As AI and generative AI (Gen AI) systems play an increasingly prominent role in research and development, the questions raised by this case are no longer merely theoretical. They carry implications for how innovation is protected in practice.

The Commissioner’s Decision: Why AI Could Not Be An Inventor

On June 5, 2025, the Commissioner of Patents refused Canadian Patent Application No. 3,137,161 ('161 Application), following a recommendation by the Patent Appeal Board (PAB)⁴.The '161 Application generally relates to a food and beverage container and a signaling device designed to attract enhanced attention.

Rather than being conceived by a human, the concepts claimed in the ’161 Application were conceived by an AI system called the Device for Autonomous Bootstrapping of Unified Sentience (DABUS). DABUS is an AI system that Mr. Thaler is said to have developed and own.

The refusal by the PAB had nothing to do with patentable subject matter, novelty or obviousness. The sole issue was inventorship. Under the Patent Act, a patent application must be filed by an "inventor or the inventor's legal representative".  Although “inventor” is not defined in the Patent Act or the Patent Rules, the PAB concluded that the ordinary meaning of the term refers to a "person".

The Appeal: What Is Being Challenged

An appeal of a Commissioner's decision is first reviewed by the Federal Court.

Mr. Thaler's appeal to the Federal Court challenges the legal conclusion that "inventor" must be limited to natural persons. In broad terms, Mr. Thaler submits that the Commissioner interpreted "inventor" too narrowly by freezing its meaning in the past. Mr. Thaler alleges that interpretation of the Patent Act should evolve to reflect new technological realities, including machines that can autonomously generate inventions. In view of this, Mr. Thaler seeks declarations that DABUS is an "inventor" under the Patent Act and that its owner, Mr. Thaler, is entitled to any intellectual property it creates.

Mr. Thaler's appeal will likely be heard by a single judge of the Federal Court in the second half of 2026. A subsequent appeal would be heard by a three-judge panel of the Federal Court of Appeal.

Implications of AI Inventorship

Much of the debate around AI inventorship is abstract, but it raises practical questions. Patent applicants are required to identify all inventors. However, as AI and Gen AI tools play an increasing role in R&D, questions arise as to how these AI systems should be treated, especially when they materially contribute to an invention.

It is important to distinguish between inventorship and ownership. Patent rights are owned by the inventor or by the company that employs the inventor (and is the recipient of an assignment of rights). In principle, an AI system could be listed as an inventor while patent rights are assigned to a human or a company. However, if AI systems cannot be listed as inventors at all, can companies maintain patent rights where inventive output is largely AI generated?

These issues may reveal itself in the pharmaceutical patent sector. In pharmaceutical discovery, AI models are used to propose novel compounds, biological targets, and formulations. Patent rights over such compounds and formulations can command extraordinary commercial value.

A useful illustration of this is AlphaFold, the AI system developed by Google DeepMind. AlphaFold has been used to generate three-dimensional protein structures and was used to solve a long-standing problem in biology: how to predict protein's complex structures from its amino acid sequences. The work produced by AlphaFold led to its human developers being awarded the Nobel Prize in Chemistry, in 2024. While the scientific accolades were awarded to the human developers, the specific discoveries were produced by the AI itself.

Accordingly, as Gen AI continues to play a growing role across multiple fields, questions around inventorship (and ownership) will become increasingly central rather than exceptional.

Conclusion

The Thaler appeal brings the question of AI inventorship squarely before the Federal Court of Canada at a time when AI-driven innovation is rapidly becoming mainstream. While the Commissioner's decision reflects what the PAB considers to be the current limits of the Patent Act, Mr. Thaler's appeal highlights growing tension between traditional concepts of inventorship and modern R&D practices.

Please note that this publication presents an overview of notable legal trends and related updates. It is intended for informational purposes and not as a replacement for detailed legal advice. If you need guidance tailored to your specific circumstances, please contact one of the authors to explore how we can help you navigate your legal needs.