Empiricism and religion
Swammerdam’s science

His life and work

Nerve function


Bees and ants

"The Bible of Nature"

Amazing drawings

Techniques and microscopy


Swammerdam’s life



A fake “portrait”

Science in society

Empiricism and religion

Mysticism and modern science

Illustrations and their meaning

Swammerdam in culture

Swammerdam's world

Friends and contemporaries

Contemporary accounts

On-line resources

Under construction:

Discussions of Swammerdam’s work

A bibliography of Swammerdam's works


Swammerdam was driven by two powerful and contradictory motivations. On the one hand, he openly embraced what he called “experimental philosophy” — the Baconian principle that favoured empirical observation and experimentation above hearsay, “authority” and pure reason. As a result, both the form and content of his research have a distinctly contemporary feel for today’s scientists.

On the other hand, virtually every page of the Book of Nature contains pantheistic exhortations to praise the “Supreme Architect” God (Christ is only mentioned three times), and uses the wonders revealed by the microscope and the dissecting instruments as proof of the glory of the Creator.

Amazed by the beauty and order he discovered in the organisms he observed and dissected under the microscope, Swammerdam could only draw one conclusion: order could not be a product of chance, it must therefore be divine. This view was hardly unusual at the time — only Darwinism would free biology of such reasoning.

Swammerdam’s opposition to spontaneous generation was not only motivated by his discoveries, but by his belief that it was “the short path to atheism”. As he explained in The Book of Nature: “For if the generation of things be so subject to chance, what prevents man from being thus as easily produced in the same manner.”

However, in repeatedly asserting that insects were as complex as higher organisms and that “The body of a beast deserves as great admiration as the human body, if we consider both in their kind and nature”, he was asserting the unicity of the natural world and unwittingly laying the basis for God’s eventual departure from the scientific scene.

Although Swammerdam’s repeated and lyrical expressions of wonder would have no place in a modern text, they are commonplace in contemporary scientific discourse, both in the informality of the laboratory and even in the more staid setting of a conference lecture. The religious framework is, of course, absent today, but the starting point — “non-scientific” expressions of beauty and awe — is essentially the same.

Swammerdam’s religious beliefs — rather vague and mystical, “more catholic than reformed” as he described them — not only informed his scientific investigations, they ultimately threatened their very existence.

In 1673-1676 he fell under the influence of the itinerant French mystic, Antoinette Bourignon (1616-1680). Bourignon, who argued that Adam was hermaphrodite, heard voices and insisted that all her followers give up their worldly goods and preoccupations to follow her and worship Christ.

Her theology — which became quite notorious in the decades after her death, and was denounced by both Catholic and Protestant churches — was a form of primitive ecumenism, arguing for the reunification of the Christian community on simple Biblical principles.

As a consequence of Bourignon’s influence, Swammerdam abandoned science for a while (she described his work as “amusements de Satan”) and even destroyed his study of the silk-worm larva (although he had the good sense to send the drawings to Malpighi — for more on this click here).

Bourignon allowed him to publish his study of the may-fly, but it was undoubtedly her influence that led him to smother his findings with pages and pages of poems and religious reflections. After nine months following Bourignon and working for her, copying out her letters and visiting high-ranking people for her in Denmark, (apparently he never went to stay on her island off the coast of Schleswig, although he did arrive in Schleswig city at the end of September 1675), a disappointed Swammerdam returned to his father’s home in Amsterdam in June 1676.

However, letters exchanged by Bourignon and Swammerdam, recently discovered by the Dutch researcher Mirjam de Baar, indicate that their relationship continued for sometime after 1676, with Swammerdam seeking her advice on a number of occasions.

Swammerdam’s scientific judgement clearly suffered during his period of full immersion in the Bourignon cult. Thus in Ephemeri Vita (1675), his monograph on the may-fly written at the height (or depth) of his religious infatuation, Swammerdam argued that “the curing of human afflictions does not depend on the knowledge of anatomy or of any other science (...) but on the fear of the Lord.”

Three years later, in the conclusion to The Book of Nature, he reiterated an earlier, more lucid appreciation of the true value of his work: “I believe physicians if they had clear and distinct ideas of the structure of our bodies, and of the motions of the blood, and other juices belonging to them, would be able to mend radically any unnatural disposition in these parts, as they could then prove the validity of such clear and distinct ideas, by reducing them to the test of experiments, which is allowed in every country to deserve credit, more than reason itself.”

Swammerdam’s most Biblical religious beliefs also came into clear contradiction with his “experimental philosophy”. Like many other early moderns, Swammerdam was highly critical of all those who blindly followed the views of the Ancients (essentially Aristotle). Indeed, he legitimately claimed that his work marked the first decisive advance on Aristotle for 2000 years! However, in one respect Swammerdam remained wedded to the argument of Authority: his view of the Bible, in particular the stories of the Old Testament.

Thus in The Book of Nature he discusses at some length the story of Samson and the lion, the bees that nested in the dead lion’s carcass and how they could have produced honey so rapidly. Even more bizarrely to modern eyes, having noted that metamorphosis in the butterfly leads to a change in the digestive apparatus, he wonders whether the Old Testament King Nebuchadnezzar, who turned into a grass-eating beast with a hairy hide and long talons and was cast into the wilderness, “did not suffer a change in his internal parts, correspondent to that which appeared in his external form”!

For an article on the relation between Swammerdam's emotional responses to the world and modern science, click here.

References about Antoinette Bourignon:

Bouquet, H (1912) Le mysticisme d’un anatomist du XVIIe siècle: Jean Swammerdam et Antoinette Bourignon, Æsculape:171-176

van der Does, M. (1974) Antoinette Bourignon: Sa Vie (1616-1680) — Son Œuvre (Amsterdam, 1974).

Lindeboom, G. A. (1974) ‘Antoinette Bourignon’s first letter to Jan Swammerdam. A contribution to his biography’, Janus, 61:183-199.

This page is partly excerpted and adapted from an article that appeared in Endeavour (2000) 24(3) pp122-128. © Elsevier Science, 2000.

To download a PDF version of the full article, click here.