lam very much in your debt for all the trouble you put yourself to for my sake, and for the concern you show yourself to have for my interests. But since I have far less of the latter than you, I should think myself guilty of an injustice if I did not beg you to ignore completely whatever you may hear against me, and not even bother to listen to it, or write to me about it. For my part, I have long known that there are fools abroad in the world, and I have so little regard for their judgement that I should be extremely sorry to lose a single moment of my leisure or my peace and quiet on their account.

As for my Metaphysics, I have completely stopped thinking about it since the day I sent you my answer to Hyperaspistes – so much so that I have not picked up the work since then. So I cannot answer a single one of the queries you sent me in your letter last week, except to say that I beg you not to give them any more thought than I do. In publishing the book I did what I thought I had to for the glory of God and to satisfy the demands of my conscience. If my project has failed, and there are too few people in the world capable of understanding my arguments, it is not my fault: the arguments are no less true for that. But it would be my fault if I got angry, or used up more time answering the irrelevant objections of those who have been in touch with you . . .

TO BEECKMAN, 24 JANUARY 1619

I have received your letter, which I was expecting. On first glancing over it, I was delighted to see your notes on music. What clearer evidence could there be that you had not forgotten me? But there was something else I was looking for, and that the most important, namely news about what you have been doing, what you are doing, and how you are. You ought not to think that all I care about is science, I care about you, and not just your intellect – even if that is the greatest part of you – but the whole man.

As for me, in my usual state of indolence I have hardly put a title to the books which, on your advice, I am going to write. But you should not think me so lazy as to fritter away all my time. On the contrary, I have never been more usefully employed – but on matters which your intellect, occupied with more elevated subjects, would no doubt despise, looking down on them from the lofty heights of science, namely painting, military architecture and above all, Flemish. You will soon see what progress I have made in this language, for I am coming to Middelburg, God willing, at the beginning of Lent …

If you look carefully at what I wrote on discords and the rest of my treatise on music, you will find that all the points I made on the intervals of harmonies, scales and discords were demonstrated mathematically; but the account I gave is too brief, confused, and not properly worked out.