Descartes – the Doubting Founder of Modern Philosophy

René Descartes, Opera Philosophica (Principia philosophiae and Specimina philosophiae).

Printed by the Blaeu Printery in Amsterdam, 1685.


What can we truly know? ‘Truly’ is the operative word here. Nowadays, this branch of philosophy is known as epistemology. Its founder was one of the titans of intellectual history: René Descartes. He also produced fundamental works in the field of mathematics and natural sciences. In 1685, two of his major works were published in the academic language of Latin in Amsterdam under the title ‘Opera Philosophica’, meaning ‘philosophical works’. Before we take a look inside, let’s just ask ourselves why this book, which was intended, above all else, to prove rather than refute the existence of God, ended up in the Roman Catholic Church’s infamous Index of prohibited books.

René Descartes after 1649, in a portrait by Frans Hals.

Descartes – Visionary and Enlightener

Our story begins in a little cabin in Ulm, in the middle of a cold night during the Thirty Years’ War. The young René Descartes was sitting by the stove, where he is said to have had some kind of vision. He was wondering what, in this world, we can actually see as it is. Our senses are unreliable, they’re always playing tricks on us. Our thoughts, perhaps? But surely they can be manipulated too? But not our doubts! When we doubt something, there can be no doubt that we are doubting. Descartes carried this fundamental realisation around with him for decades and kept coming back to it, contemplating and analysing it from every angle like a treasured piece of jewellery. It crystallised into his famous dictum: I think, therefore I am (Latin: Cogito, ergo sum), which also features in this volume.

Descartes was born in 1596 in Brittany, the son of a lesser nobleman. He enjoyed an excellent education, studied law and travelled across Europe as a mercenary, under the command of various rulers. These travels not only took him to Ulm, but also to the studies of astronomers Tycho Brahe and Johannes Kepler. This young man was convinced of two things: firstly, that there must be a universal method for searching for truth and, secondly, that he, René Descartes, was destined to discover this method.

Descartes sought out scholars with whom he could discuss and exchange ideas, and began to publish his writings. Then came a shot across the bow: the trial of Galileo Galilei made him realise that he too was treading on dangerous ground. In his ‘Treatise on the World’, Descartes was actually trying to prove the existence of God – but in a scientific work. The Church’s response to the writings of Galilei, a devout Catholic, had shown just how sensitive they were about that sort of thing. It wasn’t enough to prove the existence of God; every other aspect of the proposed worldview had to be just right. And in Descartes’ works, as we’ll see, it was not. So, to be on the safe side, he left this draft in the drawer.

Because, unlike Galilei, Descartes didn’t write in Latin. He believed, not wrongly, that his ideas were too important to be made accessible only to his fellow scholars in their ivory tower. That’s why he wrote in the language of the people (French); he considered himself an enlightener in the truest sense.

In 1637, Descartes’ ‘Discourse on the Method’ was published anonymously. This work was aimed at a wide readership in French. It wasn’t translated into Latin until 1656.

Enemies Everywhere

But this enlightenment didn’t appeal to everyone. After abandoning the treatise that attempted to prove the existence of God, Descartes published a work that also features in our edition: his ‘Discourse on the Method of Rightly Conducting One’s Reason and of Seeking Truth in the Sciences, and in addition the Optics, the Meteorology and the Geometry’ was first published in 1637 – anonymously. Nevertheless, the whole of Europe soon knew who was behind the work. Descartes had retreated to the relatively liberal Netherlands, with good reason. Although he certainly believed in God, he held the firm conviction that God had created a world that functioned independently of Him according to fixed laws. And it was the task of scholars to identify and describe these laws. So, within the natural world, there was no longer any need for an intervening God nowadays, this school of thought is known as rationalism. At the time, it was very strong stuff. Descartes faced hostility on all sides, and feared reprisals. Was he being paranoid or just careful? In any case, he wandered restlessly across Europe. He kept in contact with the great thinkers of his time, but always via a good friend in Paris, who was the only one person who knew Descartes’ changing addresses.


He Who Thinks, Is. But What Is He?

Descartes’ approach represented a radical turnaround in philosophical thinking. Up to that point, philosophers had attempted to describe the world as it is. Descartes had taken a step back and asked: what can we know in the first place? He realised that we perceive everything through the notions formed in our own heads, that we can never truly understand anything objectively. And thus, epistemology was born. Curiously, the ‘Discourse’ of 1637 is presented as a kind of autobiography. The writer demonstrates the method on his own life story and his growing understanding of epistemology. He takes the reader by the hand and explains, step by step, how to argue cleanly and clearly. There’s no mistaking the mathematician’s hand here.

Our edition features a Latin text which was first published in 1656 in Amsterdam, this time under Descartes’ name; his game of hide-and-seek was no longer necessary.

The writer takes a very practical approach, presenting his method in reference to three topics which he examines in turn: refraction of light, celestial phenomenons and analytic geometry. We can see here that this man wasn’t just a philosopher, but also a physicist, astronomer and, above all, a mathematician.

But Descartes also asks how the method would be practically applied to ethical questions. This was a much larger problem, as Descartes’ complicated, we could say infinitely meticulous, analyses would keep modern supercomputers such as Deep Blue busy for years. This is no way to solve everyday problems. So Descartes advocates a provisional system of ethics, which can be practised temporarily until definitive answers are found. A pinch of pragmatism, which allowed one to live with the high standards of perfectionism with one’s head held high.

A Matter of Principle

In 1644, a few years after his ‘Discourse’, Descartes had another book printed, this time in Latin and therefore explicitly aimed at his colleagues: the ‘Principles of philosophy’ (‘Principia Philosophiae’). This work is dedicated to his pen friend and eager student, Elisabeth of the Palatinate. To ensure his ideas would reach a wider readership, Descartes also had this book translated into French three years later. Our edition contains a later, revised version of the original Latin text.

This work represents Descartes’ big shot. It is, in fact, the first mechanistic interpretation of the world and its laws. A milestone in the history of philosophy. In the work, Descartes incidentally mentions what is now known as the law of inertia or Newton’s First Law: an object stays at rest unless acted upon by an external force. Newton later borrowed this from Descartes.

(And by the way, in §7, you’ll find the famous dictum mentioned at the beginning: ‘Cogito, ergo sum’…)

The edition printed by Blaeu in Amsterdam (that’s right, the printing house that published the first atlas) in 1685, a generation after Descartes’ death, comprises these two works, the ‘Discourse’ and the ‘Principles’, both revised Latin versions produced by the writer himself. As was customary at that time, the main writings were printed again and again; sometimes they were sold individually, and sometimes they were bound in different combinations.

By that time, the influential Jesuits had long ensured that everything Descartes had ever published was included in the Index of Prohibited Books. They didn’t care whether or not Descartes believed in God. They could not conceive of a world that could be explained without the direct intervention of God. However, this seemingly naive attempt to brush a whole new worldview under the carpet obviously didn’t stop people from printing and reading this book. For centuries, Descartes ranked among the most influential figures in the history of philosophy. When you take a look at this book, you’ll understand why.


More Interesting Resources

If you’d like to browse (virtually) through the texts, the two individual works are available online.

Although there is no digital version of our edition of the ‘Principia philosophiae’, you can find an earlier edition here.

And here is the ‘Discourse’, Latin: ‘Specimina Philosophiae’.