Go back to menu

The nail in the coffin for AI inventorship?

Thaler v Comptroller General

13 October 2021

On 21 September 2021, the Court of Appeal in England and Wales reiterated that only a human can be considered an inventor for the purposes of UK patent law. This is the latest in the growing body of test cases worldwide where Dr Stephen Thaler seeks to patent inventions created by his AI software "DABUS".


In a previous article we explored whether AI systems could be inventors for the purposes of the Patents Act 1977 (1977 Act). There is no real dispute – and it was acknowledged as much in the present case – that such systems may be technically advanced enough to be capable of devising an invention. Indeed, the appellant in the present case, Dr Thaler, acutely highlighted this point by obtaining US Patent No. 5,852,815 in his own name, later to publicise that the invention had been created solely by an artificial neural network known as DABUS.

The cases to date highlight the divergence between this technical reality of AI inventorship, where AI appears capable of "invention", and the legal framework governing patents, which precludes AI from being deemed an inventor. Under the 1977 Act, an AI machine cannot be the actual deviser of an invention, as under current English law only a natural person had been considered capable of being an inventor. Since only an inventor or someone who derives their right from the inventor is entitled to apply for a patent for that invention, AI inventions are not capable of being the subject of a UK patent application.  

The present appeal, Thaler v Comptroller General of Patents Trade Marks and Designs [2021] EWCA Civ 1374, seeks to test this interpretation of the 1977 Act. Dr Thaler filed for two patent applications, stating on the application form that, whilst he was not the inventor, he had the right to be granted the patents by ownership of the creativity machine DABUS. Against Dr Thaler's wishes, the UKIPO deemed these applications to be withdrawn as Dr Thaler's statement of inventorship form was held not to satisfy s.13(2) of the 1977 Act, which requires the applicant to identify the person they believe to be the inventor, or alternatively the derivation of their right to be granted the patent.

Whilst Dr Thaler's case had been rejected by both the UKIPO and the High Court, he appealed on the following grounds:

  • that an inventor under the 1977 Act need not be limited to a natural person;
  • that he was able to derive the right to apply for the patents based on his ownership of DABUS; and
  • that s.13(2) of the 1977 Act should not result in his application being withdrawn.
Definition of Inventor  

The primary, and fundamental, issue in this case is whether it is possible to have a non-human inventor under section 7 of the 1977 Act. Whilst s.7 does not explicitly state that an inventor must be human, the Court of Appeal judges were unanimous in finding that the premise of section 7 is that an inventor is and can only be a person. In particular, s.7 is an "exhaustive code" for determining entitlement to a patent, and it is clear that each category of grantee set out in s.7 must be a person. It follows that DABUS, or any other AI, cannot be an inventor under the Act.

Derivation of right to apply

An alternative argument advanced was that Dr Thaler was entitled to apply for patents for inventions made by DABUS under s.7(2) of the 1977 Act as he was entitled to the "whole of the property in it" by virtue of his ownership of DABUS. The Court of Appeal was not persuaded that there was any rule of law that new intangible property (here the invention) produced by existing tangible property (here DABUS) is the property of the owner of that tangible property.

Section 13(2)

Dr Thaler's appeal was rejected, but with Lord Justice Birss dissenting. Birss LJ focussed on the rebuttable presumption contained within s.7(4) of the 1977 Act that the person who makes an application for a patent shall be taken to be entitled to be granted a patent. Further, he held that section 13(2) did not cause Dr Thaler's application to be withdrawn, as Dr Thaler stated his genuine belief that there was no named inventor. This argument lent heavy weight to the policy reasons behind section 13 that a Comptroller should not review the factual basis of a patent application.

By contrast, Arnold LJ and Laing LJ found that Dr Thaler had not complied with s.13(2) as he had not identified the person he believed to be the inventor, and had instead positively asserted that there was a non-human inventor. On this basis, they upheld the UKIPO's decision that the application must be withdrawn.

Nonetheless, Birss LJ's dissenting judgment offers the possibility of further appeal to the Supreme Court. Perhaps more significantly, it reveals a body of opinion within (part of) the judiciary that AI is capable of inventing, even if this is ill-supported by the current legal framework. Laing LJ even considers in her judgment that the facts of this case could show that a machine can devise an invention.


There can be no doubt that Thaler v Comptroller has enshrined the incompatibility of AI inventorship with English law; an AI machine cannot be an inventor under the Patent Act 1977. But far from being the last nail in the coffin, it may be the impetus needed for the enactment of a new approach.  As Lady Justice Laing put it, if patents are to be granted in respect of inventions by machines, the 1977 Act will have to be amended, or as Arnold LJ put it in the context of whether Dr Thaler could derive the right to patent the invention by virtue of his ownership of DABUS, this really is an argument about what the law should be, rather than the present state of the law.

As covered in a previous article in more detail, one of the outcomes of the UKIPO's Call for Views on Artificial Intelligence and Intellectual Property was to propose a further consultation this year to consider legislative change specifically pertaining to AI-generated inventions. Interestingly in this decision, and in the decisions below, there was no real challenge to the proposition that DABUS had created the invention – as is often the case the issue is that the law has not kept pace with the technical reality.    

Since the hearing, Thaler has been successful in similar test cases in Australia and South Africa, although the relevant legislation in each case is distinct and does not restrict non-human inventorship in the same way as the 1977 Act. Whilst therefore not providing direct analogy to cases decided under English law, it demonstrates the need for the government to keep legislative pace with developments in a fast moving market, and is perhaps an indicator of things to come.

Ben Reeves, IP Trainee, London, contributed to the writing of this article