If I had the age and leisure which I had in Paris, I would hope it would serve to make the progress in physics which your first gift helped me make in geometry. But that mental vigour is quite diminished and in addition I am distracted by completely different studies which seem to require my complete attention. From time to time I manage to escape from this prison where I find myself, and the trip as far as Italy which I have just undertaken has cheered me up a bit; but now I must return more than ever to my ordinary duties, and in particular to a far-reaching historical work, laden with facts, which requires great precision.

Writing on 29 November 1691 to one of his new correspondents on religious and philosophical issues, Paul Pellisson-Fontanier, he lamented, “Here, if I think about these things, it is as on the sly. One can hardly speak to anyone.” Intellectually, Leibniz was in fact a very gregarious spirit who thrived in his treasured exchanges with other minds. He always seemed to have time for a chat and apparently had the common touch as well – the gift of conversing with uneducated people.