Pablo asked:

Dear Philosophers,

I would like to ask whether there is any reasonable explanation why many after/ today’s philosophers rather refer to Descartes than to Leibniz. Although Descartes had influenced significantly new modern era in philosophical thinking, so did Leibniz. Moreover, Leibniz proved some imperfections in Descartes metaphysics. I mean both of them deserve our attention, yet in my opinion Leibniz is somehow still in Descartes shadow. Why is that?

Thank you in advance for any tangible arguments or inspiring ideas.

Answer by Jürgen Lawrenz

There is a simple and a complex answer to this.

The simple one is that Descartes was in a sense the father of the modern scientific method. His mind/ matter dualism had the effect of enabling us to focus on matter (res extensa) as the appropriate substance for scientific research. Res cogitans (the mind) is on the contrary the instrument for ascertaining truths in relation to the material world, i.e. the instance responsible for segregating fact from fancy. This removed at one stroke a large number of dubious human preoccupations from the scientific scene, e.g. the clutter of superstitions, astrology, alchemy etc. that could not sustain the mind’s enquiry into their truth status. Thereby Descartes placed epistemology, reductive and mathematical methodology on the map, and these have occupied us ever since, leading among other things, to the triumphal march of science down to the development of digital computers.

In a word: he saddled western philosophy with so many difficult problems that we have not tired of trying to solve them ever since, and our technology has been the principal beneficiary.

In contrast, Leibniz became a victim of publications problems, both of his own doing and posthumously. The only books he ever published under his name were ‘News from China’ and ‘Theodicy’, popular tracts heavily soaked in religion. Most of his published papers are similarly circumspect and reveal very little of his authentic philosophy — in fact he once asked John Bernoulli, in whom he confided, not to reveal anything for fear of his thoughts being misunderstood! Understandable, because he was a diplomat by profession. He suffered enough mistrust on account of being a protestant working in mostly catholic countries.

So for nearly 300 years his posthumous reputation suffered from the twofold malaise that his invention of the calculus was disputed by followers of Newton and that his philosophy was seen as pure metaphysics without effective connections to the problems of real life. It meant that historically we had to cope with the notion that Leibniz fell between two stools. As a scientist he was far advanced and proposed many brilliant new ideas especially in mathematics; but as a philosopher he was (supposedly) superseded by Kant. So there were two Leibnizes: the reactionary philosopher with his head in the clouds, and the scientist with both feet on the ground. In the result, his philosophy was read by philosophers, and his science by scientists, without either of these groups taking much notice of each other or of the Leibniz who was the author of both clutches of writings.

This is where the complex answer comes in.

Leibniz himself said that you cannot understand his philosophy without consulting his science, and vice versa. But his interpreters ignored this injunction. And so philosophers concentrated on a small handful of his papers (e.g. Monadology) as the full expression of his philosophy, which resulted in an impression that fundamentally his thinking on metaphysics looked backward rather than forward and was best regarded as a sort of idealism without any genuine importance to our modern understanding of the world. The hundreds of papers and letters that convey a totally different picture were left in the archives. No-one understood them anyway. Scientists curious about his philosophy were directed to these papers by their philosophical confreres and found nothing of value in them. As recently as 1945 Bertrand Russell (who admired Leibniz) repeated this mistake by telling his readers that Leibniz’s philosophy was nothing but a logical exercise, and that its impact on him was that of a philosophical fairy tale. With friends like these, who needs enemies?

Yet when Einstein got to reading one of Leibniz’s less well-known papers, he said, if only I had known, it would have saved me years of struggling with relativity (some of his ideas were already hidden in Leibniz’s philosophy). Today a small handful of theoretical physicists like Julian Barbour or Lee Smolin have seen the light, but the underappreciation of Leibniz as a pioneer in philosophy persists. And if you pick up almost any one of the standard philosophical interpretations of Leibniz today, you will still find him categorised as ‘two Leibnizes’, of whom only one is genuinely relevant to us.

And so, to put it in a nutshell: Ever since his death, philosophers have read Leibniz’s philosophy in a certain light that is at least 50% the wrong way around — namely in disregard of Leibniz’s explicit injunction to read his companion papers on dynamics. Nothing of this kind ever happened to Descartes, who published very little and repeated himself constantly in those few writings. But although Leibniz’s pioneering papers have at last come to light in the last 30 years, the academic industry is still largely committed to the ‘old’ out of date Leibniz. The most recent student editions continue this tradition of narrow, selective readings of papers that all concentrate on his supposedly ‘idealistic’ frame of mind.

So there is your answer. I guess some day this lopsided point of view is going to be revised. I’ve written 2 books in the last 10 years on this state of affairs; but it would be over-optimistic of me to claim that they’ve made an impact. Yet ‘hope springs forever’. It is certainly high time that the study of Leibniz reveals the authentic greatness and importance of his thought for us today. If nothing else, Leibniz solved the philosophical problem of Descartes’ dualism 300 years ago; but we don’t know it yet and thus continue to invest billions of research dollars on projects that even on Descartes’ own say-so are not subjects of scientific enquiry.