By Sebastian Olden-Jørgensen

During his studies in the Netherlands, Steensen had come into contact with a philosophical trend which influenced him deeply.  This was Cartesianism, named after the great French philosopher, René Descartes (1596-1650). Descartes plays a critical role in the history of philosophy, but here we will focus on two points alone.  First, Cartesianism was a theory regarding proper scientific method. One of its basic tenants, the basis of all modern science, is to question everything and put everything to the test. This was exactly the sort of maxim which made sense to Niels Steensen. Through his experiments he had observed many  incongruities between what was held to be common knowledge and what he saw.

But Cartesianism was more than a methodology which ensured results. Cartesianism was also an ideology, indeed quite a materialist and mechanist/deterministic ideology, which had only supercilious contempt for Christianity, although this, for obvious political reasons, was seldom voiced openly. In many ways Cartesianism can be likened to the Marxist wave at universities in the 1960’s-1980’s.  One finds the same mixture of science and ideology founded upon premises assumed to be scientifically sound, even identical with science.

During his student years in Copenhagen, Niels Steensen had encountered Cartesianism, and in terms of method, he remained a Cartesian until his dying day. In the Netherlands he experienced Cartesianism as an ideology and encountered the  multiplicity of outlooks on life which thrived in the relative tolerance there. This plunged him into a deep religious crisis, which almost transformed him into an atheist Cartesian, a crisis which was only first resolved when he converted to Catholicism in 1667.

The first step towards resolving the crisis was a series of anatomical observations which convinced him that the heart was a muscle, not the seat of the emotions the Cartesians held it to be. This made him sceptical of the Cartesian ‘gurus’, because he thought: If they can be wrong about materials things which can be easily investigated by simple observation, why should one believe them when they pronounce themselves on metaphysical matters such as the soul and God?

Even after Steensen had liberated himself from overweening respect for the Cartesians, their view of, or criticism of religion, troubled his soul. According to the Cartesians, one religion was as good as another. Religion was simply a human device which allowed man to express his gratefulness to his creator and this could be done equally well within Christianity, Hinduism or Buddhism.  For those enlightened ones who had realized this, it was enough to adapt to one’s surroundings and adopt the religion of whichever country one happened to find oneself in. The thought that there was one true faith, revealed and prescribed by God, was to the Cartesian, an expression of ignorant naiveté.

When Steensen lost faith in the infallibility of the Cartesian scientists, he began to question their understanding of religion as well. But what was the alternative? His faith was shaken and he could not fall back on the Lutheran faith of his fathers, his years abroad had made that impossible for him. There he had witnessed Christian churches arguing one against each other, each claiming to have support in the Bible for their point of view: sola scriptura. Their disagreement was also reflected in their translations of the Bible. Steensen concluded that this formal principle, sola scriptura, was not sufficient basis for true Christianity.

The Cartesian answer of course, was that there was no one true form for Christianity, that all were equally good or bad. To a Cartesian the question was scarcely relevant, it was simply a practical question of adapting. Then Steensen became aware of the Catholic Church. The formal principle of the Catholic Church is not scripture alone, but tradition (including scripture) as it is entrusted a particular, concrete religious community: the Catholic Church. Here was a genuine alternative to the lukewarm Cartesianism religiosity.