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Brunelleschi's egg and hindsight in patentability

Date: 19 April 2021

If third parties are indignant at the alleged banality of a technical solution presented by your research & development department, get in touch with us. It may well be a patentable invention... Find out what the dome of Santa Maria del Fiore in Florence has to do with a broken egg and what the broken egg has to do with indignation, hindsight and ultimately patent law.


Filippo Brunelleschi


575 years ago, on 15 April 1446, Filippo Brunelleschi, one of the leading Italian architects and sculptors of the early Renaissance, died. Not only did Brunelleschi discover geometrically constructible perspective, but he was also an active inventor. In 1421 Brunelleschi received the first ever patent for an industrial invention - a ship with a lifting device for transporting marble. Brunelleschi invented a change gear for a lifting crane for the construction of the dome of the Florentine cathedral, which eliminated the need to re-harness the animals used to operate the crane. This allowed him to significantly shorten the construction time of the dome.


The egg and the dome


That Brunelleschi had a good grasp of the concepts of inventive activity and improper retrospective observation is suggested by the following anecdote attributed to Brunelleschi by the Italian artist Giorgio Vasari (1511 - 1574). In another form, this story is also known as "The Egg of Columbus". By solving the problem of placing an egg upright on a tabletop, Brunelleschi is said to have been commissioned to build the dome of Florence Cathedral.


During consultations with his colleagues, Brunelleschi's theoretical concept for building the dome of the cathedral was criticised as being impossible to execute. Brunelleschi understandably did not want to reveal his concrete model to further illustrate the concept before the contract was awarded. The question remained as to which architect should be commissioned to build the dome.


According to legend, Brunelleschi suggested that whoever succeeded in placing an egg upright on a tabletop should be awarded the contract to build the dome. After all his colleagues had failed to solve this task, Brunelleschi took an egg and pressed it with its tip first onto the tabletop. The egg stood upright and his colleagues were indignant. This solution to the problem was not art! Anyone could have thought of that. Brunelleschi replied with a smile that the construction of the dome would no longer be difficult for any of the colleagues present once they had seen his model.


Brunelleschi was awarded the contract to build the dome. The fact that the dome of Santa Maria del Fiore in Florence has the shape of an egg pressed in at the top may be a coincidence.


Inventive activity and inadmissible hindsight


The anecdote is not only entertaining, but also illustrates a principle that applies in patent law examination for inventive step of an invention.


It is well known that patents are granted for inventions that are not only new but also inventive. A technical solution is inventive if it cannot be considered obvious to the person skilled in the art in the relevant technical field from the prior art known to date. This principle is applied in a similar or comparable manner by all examining patent offices.


When answering the question whether a technical solution is to be regarded as obvious or not against the background of the prior art, the so-called 'inadmissible retrospective view' with knowledge of the invention must be avoided. The inadmissible retrospective view with knowledge of the invention prevents an objective assessment of the contribution by which the invention enriches the prior art.


As was the case with Brunelleschi some 500 years ago, it is still the technical solutions that are strikingly simple in retrospect that are convincing in practice. Often, the very technical solutions that third parties inadmissibly dismiss as banal in retrospect constitute patentable inventions.




Unfortunately, the mechanisms of inadmissible retrospective consideration are also all too well established in development departments of companies. A simple but ingenious solution to a technical problem is quickly dismissed as banal and, above all, not patentable by third parties who were not involved in the solution.


Our experience shows: If indignation about the alleged banality of a proposed technical solution is raised within a development team, IP managers should take notice and think of their patent attorneys. It is precisely in such supposedly banal solutions that patentable inventions are often hidden, which are particularly interesting for competitors precisely because of their simplicity, because they are easy to implement.


If outrage over banal solutions is getting louder in your development department, get in touch with us. Our experts will be happy to advise you on all aspects of IP protection rights.


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