Peter Forsskål – Linnaean apostle, Enlightenment philosopher and press freedom activist
Peter Forsskål.
- Peter Forsskål (1732–1763) was a Swedish Enlightenment philosopher and advocate for freedom of the press.
- Perhaps his most significant contribution to public debate was his publication Thoughts on Civil Liberty (1759), which was censored by the authorities.
- His ideas helped Sweden adopt the world’s first Freedom of the Press Act in 1766.
- Peter Forsskål was a pupil of Carl Linnaeus and a versatile scholar.
- He took part in a scientific expedition to the Middle East but died of malaria in Yemen at the age of just 31.
Peter Forsskål was just ten years old when he was enrolled at Uppsala University in 1742. He began his academic studies in 1750. One of his teachers was Linnaeus, who appreciated his intelligence, ambition and keenness to engage in debate.
After graduating in 1753 with the assessment “exceptional”, Forsskål travelled to the University of Göttingen. There he encountered one of Europe’s most modern academic institutions: research and teaching were integrated and there was no clerical censorship. The academic freedom he saw there made a great impression on him.
“If we only had the freedom to think and write in Sweden that they enjoy in England and Germany, it would be even more obvious that the cold climate does the mind no harm.”
Philosophical rebel with international impact
In Göttingen, Forsskål obtained a doctorate with a thesis entitled Dubia de principiis philosophiae recentioris (Doubts Concerning the Principles of Recent Philosophy). In it, he attacks Wolffian philosophy, which reigned supreme in the Lutheran Church at the time.
Forsskål is not an atheist, but he dismisses several of the so-called proofs of God’s existence, including Descartes’s ontological proof (“God is perfect, and consequently must exist”). He also argues that morality is not dependent on religion, but derives from human nature. The thesis attracted widespread attention and made a great impression on Immanuel Kant.
Forsskål drew inspiration both from the Scottish philosopher David Hume and from Linnaeus’s empiricist motto: “In science, theory must be corroborated by observation.”
The fight for freedom of expression
Back in Uppsala in 1756, Forsskål continued his studies while supporting himself as a tutor. In spring 1759 he applied to submit the thesis De libertate civili (On Civil Liberties), in which he argued for unrestricted freedom of the press. His application was rejected. The subject was far too sensitive.
However, a slightly watered-down Swedish version, Tankar om borgerliga friheten (Thoughts on Civil Liberty), passed the censor and Forsskål had 500 copies printed, which he distributed to students in Uppsala. But at this point the government intervened. Forsskål received a warning and the University’s vice-chancellor – who happened to be Linnaeus at the time – was ordered to confiscate and destroy the “outrageous” pamphlets. Linnaeus managed to collect 79 copies, after a certain amount of pressure from higher up.
The heavy-handed intervention achieved the opposite of the intended effect: the ideas spread all the more successfully. Forsskål asserted that he had not broken any law and demanded to be informed which regulations he had supposedly violated – but he received no answer.
“A wise government therefore allows the people to express their dissatisfaction with the pen rather than with other weapons.”
Towards the world’s first freedom of the press act
Ideas of liberty were in the air at the time, and citizens’ rights had some advocates in the Riksdag. Nonetheless, even if Forsskål was not alone in driving this issue, it is obvious that Thoughts on Civil Liberty inspired the movement that in 1766 led to:
- The abolition of censorship
- The world’s first act on the freedom of the press
- The introduction of the principle of public access to official documents
In 2023, the Swedish Freedom of the Press Act was inscribed as one of Sweden’s contributions in the UNESCO Memory of the World Register.
Titelblad , Tankar om borgerliga fritheten, 1759.
The journey to Arabia Felix – science, adventure and a life that ended too early
In 1759, the theologian and orientalist Johan David Michaelis in Göttingen proposed to King Fredrik V of Denmark that he should finance a scientific expedition to the Orient. Whom should Michaelis propose in the field of natural history? Peter Forsskål!
Forsskål was a biologist, a philosopher – and he spoke Arabic. The offer came with a professorship in Denmark and, encouraged by Linnaeus, he accepted. However, the expedition did not set out until January 1761.
In Egypt and Yemen – scientist, diplomat, explorer
The journey proceeded via Egypt and the Red Sea to Yemen. It was a journey full of hardships, illnesses and internal conflicts. Forsskål became the expedition’s spokesman; he could communicate with bureaucrats and camel-drivers alike, and had adopted the practical Arabic clothing.
On his own or accompanied by astronomer Carsten Niebuhr, he explored the mountainous regions of Yemen and collected large numbers of plants and animals. One of the expedition’s tasks was to identify plants named in the Bible. To Forsskål’s delight, he found the Opobalsamum or Balm of Mecca tree. Whether it really corresponds to the Balm of Gilead mentioned in the Old Testament is uncertain, but Linnaeus did not hesitate and named Forsskål’s find Amyris giliadensis.
A letter from the realm of the dead
On 11 July 1763, Peter Forsskål died of malaria in Yerim, just 31 years old. A month earlier, he had sent a letter to Linnaeus from the city of Mokha, famous for its coffee. The envelope contained a twig from the balsam tree. When the letter reached Uppsala, Linnaeus had already heard that his pupil was dead.
He wrote to the astronomer Wargentin: “Yesterday I received a letter from the realm of the dead from the late Forsskål ... I felt giddy at such unheard-of news. A stalk with flowers lay in the letter.”
The legacy of the expedition
Carsten Niebuhr was the only survivor of the expedition. Thanks to him, much of the material was saved for posterity, including:
- Forsskål’s herbarium and parts of his collection of animal specimens
- The manuscript of Flora Aegyptiaco-Arabica and Descriptiones Animalium
- Hundreds of drawings and notes
Forsskål’s handwriting and abbreviations were difficult to decipher and the printed Flora from 1775 contains several misinterpretations. However, Forsskål’s name lives on – literally. Many plant and animal species bear the species epithet forsskaolii. One example is Ruellia forsskaolii, named as recently as 2016 by Uppsala botanist Mats Thulin, who has traced Forsskål’s footsteps in Yemen.
Forsskålea tenacissima – a tribute, not a gibe
Linnaeus honoured his pupil by naming a peculiar plant that Forsskål had found near Cairo Forsskålea tenacissima. The species epithet tenacissima means “very tough” or “persistent”; it refers to the plant’s tough fibres, but could also be a tribute to Forsskål’s character.
A myth grew up early on that Linnaeus bore Forsskål ill will and that the choice of this plant was a gibe – but this is simply a made-up story based on misinterpretations. Their correspondence conveys a completely different picture: warmth, respect, humour and friendship.
It is sometimes alleged, again completely without foundation, that Forsskål was forced to go into exile, but the expedition was planned, and Forsskål a Danish professor, long before Thoughts on Civil Liberty was published. Forsskål looked forward to returning home with honour and rich collections.
Forsskaolea tenacissima, N.J. von Jacquin, Hortus botanicus Vindobonensis, vol. 1: t. 48 (1770)
A short life – a great impact
Historian Henrik Schück describes Forsskål’s life as “one of the most precious pages in the history of Swedish science”. Modern researchers regard his notes and collections as the most important contribution to the natural history of the Middle East in the 18th century.
Though he only lived to the age of 31, his ideas changed Sweden – and his research made an impact.
Peter Forsskål and Uppsala University today
Peter Forsskål’s work Thoughts on Civil Liberty was a strong contributing force to the creation of the Freedom of the Press Act that we now take for granted in Sweden. Freedom of the press, in turn, is an absolutely essential foundation for the academic freedom upon which today’s education and research rely heavily. Without these cornerstones, the university and higher education would never have become what they are today.
Every November, the Faculty of Law organises the Forsskål Symposium to honour the achievements and ideas of the Enlightenment philosopher Peter Forsskål. The symposium also aims to foster continued dialogue on freedom of speech in our time.
Memorial plaque for Forsskål
In 2026, as part of the preparations for its 550th anniversary, Uppsala University launched the project Historical Figures in the City. The project aims to highlight individuals and stories about scientific breakthroughs, social engagement and cultural contributions that have shaped the past, present and future.
Peter Forsskål was honoured on 12 February 2026 with a memorial plaque on Övre Slottsgatan 4 in Uppsala.
If you have a suggestion for a person with a connection to Uppsala University who should be honoured with a memorial plaque, please send your suggestion to kommunikation@uu.se.
Vice-Chancellor Anders Hagfeldt and Erik Pelling are working together to put up the commemorative plaque.
Vice-Chancellor Anders Hagfeldt and Erik Pelling from Uppsala City Council stand next to the Forsskål memorial plaque at Övre Slottsgatan 4 in Uppsala. In the background are standard-bearers from, among others, the Uppland Nation.
