In 1662 Oldenburg strongly advises Spinoza not to hesitate about publishing some work relating partly to theology, partly to philosophy, which means presumably the "Tractatus Theologico-Politicus."
I would by all means advise you not to begrudge to men of letters the ripe fruits of your ingenuity and learning in philosophy and theology, but let them go forth into the world, notwithstanding any possible grumbling from petty theologians. Your commonwealth is most free [Oldenburg was writing from England]; and therein the philosopher should work most freely. … Come then, my friend, cast out all fear of stirring up the feebler folk of our time against you; we have sacrificed enough to their ignorance and trifling scruples; let us spread our sails to the wind of true knowledge, and search out the secrets of nature more thoroughly than has yet been done. In Holland I should think it will be quite safe to print your treatise, and there is no reason to fear its giving the least offence, among men of learning at any rate. If such are your promoters and patrons — and such, I answer for it, you will find — why should you fear the detraction of the ignorant?[1]
In the following year Oldenburg was again pressing Spinoza to finish and publish a little book on "The Amendment of the Understanding," of which we now have only a fragment, published among the "Opera Posthuma."
Surely, my excellent friend, I believe nothing can be published more pleasant or acceptable to men of true learning and discernment than a treatise such as yours. This is what a man of your wit and genius should regard, more than what pleases theologians, as their manner now is; they care less for truth than for their own advantage.
And he conjures Spinoza by the bond of their friendship, by every duty of increasing and spreading abroad the truth, not to withhold the publication, or, if he indeed has grave reasons for withholding it, at least to write and explain them.[2] Oldenburg was a sincere friend to Spinoza, and a person worthy of all respect; but one cannot help observing that it is extremely easy for a man to be thus valiant in counsel when he does not risk anything on his own part. When Oldenburg in later years became better acquainted with Spinoza's results, he was himself not a little taken aback. Now, in spite of answers which were not encouraging, Oldenburg returned again and again to the charge he would never desist till his request was satisfied; meanwhile it would be the greatest possible favor if Spinoza would give him some summary of the contents of the treatise. All this while Spinoza and Boyle were holding a scientific correspondence on chemistry and pneumatics in the form of long messages contained in the letters between Spinoza and Oldenburg, though they seem to have exchanged nothing directly. There is no doubt that Boyle knew a good deal of Spinoza, and took much interest in his work. In 1665 Oldenburg writes: "Mr. Boyle and I often talk of you and of your learning and philosophy." Boyle is also mentioned as joining in Oldenburg's exhortations to Spinoza to persevere in philosophical research. We find allusions in Oldenburg's letters of this time to the miseries of the plague and of the war between England and Holland. A certain book about which Spinoza had asked has not yet reached England "because the plague has almost put an end to all communication, besides which this fearful war brings a very Iliad of mischiefs (nonnisi malorum Iliada) in its train, and is like to leave but little civility in the world." He adds that though the meetings of the Royal Society are suspended, Boyle and others go on working in private.
After 1665 there is an unexplained break of ten years in this correspondence, which is but imperfectly supplied by letters between Spinoza and other persons.
The most interesting of Spinoza's other correspondents is Simon de Vries. He was a man younger than Spinoza, his pupil in philosophy, and of much promise. He died in his master's lifetime, having shown his gratitude by material benefactions so far as he was allowed. Once he offered Spinoza a present of two thousand florins; this was declined. He was unmarried, and it was his intention to make a will leaving the bulk of his property to Spinoza. But Spinoza, knowing that Simon de Vries had a brother living, pressed on him the duty of thinking first of his own kindred; so that De Vries finally made the brother his heir, and charged his estate with an annuity of five hundred florins to Spinoza. After his death Spinoza would not entirely accept even this; when the annuity came to be paid in due course, he refused to take more than three hundred florins, which he said was quite enough for him. The letters between Spinoza and his young friend belong to the year 1663, and throw light both on Spinoza' s manner of life and on the growth of his philosophical system. They show that the leading definitions and propositions of the
