Thaler v Comptroller-General: Part 1 - AI systems cannot be an inventor under the Patents Act

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The specification and claims of Dr Thaler's UK patent applications read very much like any other patent applications. The first suggestion that something is unusual comes on the front page of the published applications. Dr Thaler is mentioned as the applicant but the inventor is listed as "Not Yet Decided". This is not because Dr Thaler is unsure of the identity of the inventor; he is certain that the inventions were devised by an artificially intelligent system he created known as "DABUS".

But if this is true, how does it fit with the existing patent system? Can a patent be granted for an invention with an AI inventor, and who should be entitled to the grant of such a patent?

The English courts have provided their answer to these questions in the form of a decision by Mr Justice Marcus Smith regarding Dr Thaler's appeal from the rejection of his UK applications by the UKIPO. The Court's decision to refuse the appeal (and thereby uphold the UKIPO's decision to reject the applications) was not unexpected. Extending the definition of "inventor" under the Patents Act to non-humans would have involved a significant departure from conventional views on the entities which are able to engage in the process of thought (although denying that non-humans can engage in thought is very much a modern exception to the historical norm when the full sweep of human history is taken into account). However, notwithstanding the result, the decision in Stephen L Thaler v The Comptroller-General of Patents, Designs And Trade Marks [2020] EWHC 2412 (Pat) provides a comprehensive analysis of the concept of inventorship and ownership of the right to apply for a patent in the UK, and how those concepts apply AI systems. The Thaler decision is therefore essential reading for those who use AI in the process of innovation. Part 1 of this article recaps the story so far and summarises the Court's decision. Part 2 explores two questions left unanswered by the Thaler decision and looks ahead to how the law may evolve in future.

30 Second Summary: What did the Court say?

  • Every invention needs at least one inventor.
  • The term "inventor" in the Patents Act 1977 only includes natural persons; it excludes AI systems.
  • Only natural or legal persons can apply for patents or transfer to another the right to apply for a patent.
  • Ownership of an AI system is not sufficient to give rise to the right to apply for a patent for an invention devised by that system.

The UKIPO's Approach to Dr Thaler's DABUS applications

Dr Thaler's applications were clearly intended to test whether a non-human can be regarded as an inventor under the Patents Act. In documents filed with the UKIPO Dr Thaler asserted that inventorship should not be confined to natural persons but should also extend to other things which are capable of invention. Dr Thaler further asserted that the person with the right to apply for a patent for such an invention should be the owner of the thing which devised the invention.

The UKIPO did not agree. Following receipt of the Dr Thaler's applications in November 2018, the UKIPO updated the Manual of Patent Practice in October 2019 to include the following practice note: 

Where the stated inventor is an ‘AI Inventor’, the Formalities Examiner [should] request a replacement [Patents Form 7]. An ‘AI Inventor’ is not acceptable as this does not identify ‘a person’ which is required by law. The consequence of failing to supply this is that the application is taken to be withdrawn under section 13(2) [of the Patents Act 1977].”

In December 2019 a Hearing Officer issued a decision holding that Dr Thaler's applications should be treated as withdrawn under section 13(2) of the Patent Act as Dr Thaler had failed to identify the person who he believed to be the inventor, and how he derived his right to be granted a patent for the inventions. In reaching this conclusion the Hearing Officer held that because DABUS was a machine, and not a natural person, it could not be regarded as an inventor for the purposes of the Patents Act. He also held that Dr Thaler had not obtained the right to apply for the invention because DABUS, as a machine, could not own anything capable of being transferred and did not have the capacity to transfer any legal rights.

The Court's Analysis

Dr Thaler appealed the Hearing Officer's decision on a number of grounds. Arguments that the UKIPO's update to the Manual of Patent Practice had prevented Dr Thaler from obtaining a fair hearing, and that the Hearing Officer had adopted an incorrect purposive construction of the Patents Act based on wider policy considerations, were swiftly dismissed. Instead the Court focused on Dr Thaler's arguments that the UKIPO was wrong to treat his applications as withdrawn because he had complied with section 13(2) of the Patents Act by identifying who he believed to be the inventor (DABUS) and how he derived his right to be granted a patent for the invention (by virtue of his ownership of DABUS).

In rejecting this submission Smith J explained that, while section 13 refers to the state of mind of the applicant (i.e. who the applicant believes to be the inventor), Dr Thaler's subjective belief alone was not sufficient to entitle him to the grant of a patent. Instead section 13 must be read in the context of the scheme set out in section 7, which (as emphasised by the House of Lords in Yeda v Rhone-Poulenc [2007] UKHL 43) provides an exhaustive code for determining who is entitled to the grant of a patent. While the Patents Act proceeds on the assumption that the person who makes the application is the person entitled to be granted the patent (s7(4)), this presumption is rebuttable. This enables the UKIPO to reject applications where the applicant's belief regarding the identity of the inventor, or their entitlement to be granted a patent for the invention, are incapable of justification under the scheme set out in section 7.

Having rejected Dr Thaler's arguments regarding section 13, the Court went on to consider the application of section 7 to the present situation. The starting point was that section 7(1) clearly limited the right to apply for a patent to "persons" and it was common ground between Dr Thaler and the UKIPO that DABUS was not a natural or legal person. Dr Thaler was both the applicant and a natural person and his applications therefore overcame this first hurdle. However section 7(2) specified that a patent could only be granted to three classes of person: (a) inventors; (b) persons entitled to the whole of the property in an invention; or (c) successors in title to either of (a) or (b). The key question was whether Dr Thaler fell under any of these three classes.

Class (a): Could Dr Thaler be granted the patents as the inventor (and does an inventor need to be a natural person under the Patents Act)?

Dr Thaler maintained that he was not entitled to be granted the patents under s7(a) because he was not himself the inventor. Instead he argued that DABUS was the inventor but accepted that it was not entitled to be granted the patents as it was not a person. While this precluded reliance on s7(2)(a), Smith J went on to consider the scope of the term "inventor" under the Patents Act, as a core element of Dr Thaler's submissions was that the term should be extended beyond natural persons and should also cover things capable of inventing (which Dr Thaler argued included DABUS). Smith J found a number of reasons why, properly understood, the term "inventor" under the Patents Act must be limited to natural persons.

The starting point was section 7(3) which specifics that the inventor is the "actual deviser" of the invention. Lord Hoffman indicated in Yeda that the actual deviser was the "natural person who came up with the inventive concept". Smith J also found support for limiting "inventor" to natural persons and not legal persons in the requirement for an invention to involve an inventive step, in the sense it was not obvious to the person skilled in the art. Smith J found it hard to envision how an inventive step could be attributed to a legal person (e.g. a company) without also striking the mind of the agents through which it acts and thus how a non-natural person could be the actual deviser of an invention. This distinction between natural persons (who could be inventors) and legal persons (who could not) was also consistent with the scheme for employee inventions under the Patents Act, which considers the employee to be the inventor with the primary right to apply for the patent (subject to the property in that right automatically transferring to the employer), permitting them to apply for the patent under 7(2)(b).

Class (b) and (c): Had Dr Thaler acquired the right to apply for the patents?

Referring again to Yeda, Smith J concluded that while class (a) relates to the first creation of the right to apply for a patent, classes (b) and (c) relate to the transfer of that right to some other person. Unlike class (a), which refers to the "inventor", classes (b) and (c) refers to "any person" and there was no intrinsic reason why they should not extend to both natural and legal persons. However, although Dr Thaler was a person and capable of receiving a right to apply for a patent under class (b) or (c), DABUS was not a person and not capable of holding or transferring property to Dr Thaler. Combined with Smith J's finding regarding the scope of "inventor", Dr Thaler faced the problem that there was nothing to be transferred to him and nobody capable of transferring it.

In reaching this conclusion Smith J rejected Dr Thaler's proposal that he had acquired the right to apply for the patents based on his ownership of DABUS. In support of this Dr Thaler pointed to a general principle that the owner of a thing (e.g. a fruit tree) is the owner of the fruits of that thing, and discussion in academic commentary regarding the provisions of the Copyright, Designs and Patents Act 1988 regarding ownership of (copyright) works. Smith J was not convinced. The discussion regarding ownership of copyright works arose from a specific legislative provision relating to computer generated works which was carefully framed for that particular context. No such provision had been included in the Patents Act and patents differed from copyright works and fruits of a fruit tree in that they did not arise automatically and require an application which must be done by a person. Ownership of an AI system was therefore not sufficient to provide the owner with the right to obtain a patent for an invention devised by an AI system.


Following the Thaler decision, and pending any further appeal, the UK's position on AI inventors is in some respects very clear; under the Patents Act AI systems cannot themselves be named as an inventor and the right to apply for an invention must originate from a human inventor. However the decision leaves two unanswered questions, which we discuss in Part 2.