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LETTER XXV. a.: Oldenburg to Spinoza. - Benedict de Spinoza, The Chief Works of Benedict de Spinoza, vol. 2 [1662]

Edition used:

The Chief Works of Benedict de Spinoza, translated from the Latin, with an Introduction by R.H.M. Elwes, vol. 2 De Intellectus Emendatione - Ethica. (Select Letters). Revised edition (London: George Bell and Sons, 1901).

Part of: The Chief Works of Benedict de Spinoza, 2 vols.

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LETTER XXV.a.

Oldenburg to Spinoza.

[Oldenburg adduces certain further objections against Spinoza’s doctrine of necessity and miracles, and exposes the inconsistency of a partial allegorization of Scripture.]

To the most illustrious Master Benedict de Spinoza Henry Oldenburg sends greetings.

In your last letter,2 written to me on the 7th of February, there are some points which seem to deserve criticism. You say that a man cannot complain, because God has denied him the true knowledge of Himself, and strength sufficient to avoid sins; forasmuch as to the nature of everything nothing is competent, except that which follows necessarily from its cause. But I say, that inasmuch as God, the Creator of men, formed them after His own image, which seems to imply in its concept wisdom, goodness, and power, it appears quite to follow, that it is more within the sphere of man’s power3 to have a sound mind than to have a sound body. For physical soundness of body follows from mechanical causes, but soundness of mind depends on purpose and design. You add, that men may be inexcusable,1 and yet suffer pain in many ways. This seems hard at first sight, and what you add by way of proof, namely, that a dog2 mad from having been bitten is indeed to be excused, but yet is rightly killed, does not seem to settle the question. For the killing of such a dog would argue cruelty, were it not necessary in order to preserve other dogs and animals, and indeed men, from a maddening bite of the same kind.

But if God implanted in man a sound mind, as He is able to do, there would be no contagion of vices to be feared. And, surely, it seems very cruel, that God should devote men to eternal, or at least terrible temporary, torments, for sins which by them could be no wise avoided. Moreover, the tenour of all Holy Scripture seems to suppose and imply, that men can abstain from sins. For it abounds in denunciations and promises, in declarations of rewards and punishments, all of which seem to militate against the necessity of sinning, and infer the possibility of avoiding punishment. And if this were denied, it would have to be said, that the human mind acts no less mechanically than the human body.

Next, when you proceed to take miracles and ignorance to be equivalent, you seem to rely on this foundation, that the creature can and should have perfect insight into the power and wisdom of the Creator: and that the fact is quite otherwise, I have hitherto been firmly persuaded.

Lastly, where you affirm that Christ’s passion, death, and burial are to be taken literally, but His resurrection allegorically, you rely, as far as I can see, on no proof at all. Christ’s resurrection seems to be delivered in the Gospel as literally as the rest. And on this article of the resurrection the whole Christian religion and its truth rest, and with its removal Christ’s mission and heavenly doctrine collapse. It cannot escape you, how Christ, after He was raised from the dead, laboured to convince His disciples of the truth of the Resurrection properly so called. To want to turn all these things into allegories is the same thing, as if one were to busy one’s self in plucking up the whole truth of the Gospel history.

These few points I wished again to submit in the interest of my liberty of philosophizing, which I earnestly beg you not to take amiss.

Written in London, 11 Feb., 1676.

I will communicate with you shortly on the present studies and experiments of the Royal Society, if God grant me life and health.

LETTER XXVI. (VIII.)

Simon de Vries1to Spinoza.

[Simon de Vries, a diligent student of Spinoza’s writings and philosophy, describes a club formed for the study of Spinoza’s MS. containing some of the matter afterwards worked into the Ethics, and asks questions about the difficulties felt by members of the club.2 ]

Most Honourable Friend,—

I have for a long time wished to be present with you; but the weather and the hard winter have not been propitious to me. I sometimes complain of my lot, in that we are separated from each other by so long a distance. Happy, yes most happy is the fellow-lodger, abiding under the same roof with you, who can talk with you on the best of subjects, at dinner, at supper, and during your walks.1 However, though I am far apart from you in body, you have been very frequently present to my mind, especially in your writings, while I read and turn them over. But as they are not all clear to the members of our club, for which reason we have begun a fresh series of meetings, and as I would not have you think me unmindful of you, I have applied my mind to writing this letter.

As regards our club, the following is its order. One of us (that is everyone by turn) reads through and, as far as he understands it, expounds and also demonstrates the whole of your work, according to the sequence and order of your propositions. Then, if it happens that on any point we cannot satisfy one another, we have resolved to make a note of it and write to you, so that, if possible, it may be made clearer to us, and that we may be able under your guidance to defend the truth against those who are superstitiously religious, and against the Christians,2 and to withstand the attack of the whole world. Well then, since, when we first read through and expounded them, the definitions did not all seem clear to us, we differed about the nature of definition. Next in your absence we consulted as our authority a celebrated mathematician, named Borel:3 for he makes mention of the nature of definition, axiom, and postulate, and adduces the opinions of others on the subject. But his opinion is as follows: “Definitions are cited in a demonstration as premisses. Wherefore it is necessary, that they should be accurately known; otherwise scientific or accurate knowledge cannot be attained by their means.” And elsewhere he says: “The primary and most known construction or passive quality of a given subject should not be chosen rashly, but with the greatest care; if the construction or passive quality be an impossibility, no scientific definition can be obtained. For instance, if anyone were to say, let two two straight lines enclosing a space be called figurals, the definition would be of non-existences and impossible: hence ignorance rather than knowledge would be deduced therefrom. Again, if the construction or passive quality be possible and true, but unknown or doubtful to us, the definition will not be good. For conclusions arising from what is unknown or doubtful are themselves uncertain or doubtful; they therefore bring about conjecture or opinion, but not certain knowledge.

Jacquet1 seems to dissent from this opinion, for he thinks that one may proceed from a false premiss directly to a true conclusion, as you are aware. Clavius,2 however, whose opinion he quotes, thinks as follows: “Definitions,” he says, “are artificial phrases, nor is there any need in reasoning that a thing should be defined in a particular way; but it is sufficient that a thing defined should never be said to agree with another thing, until it has been shown that its definition also agrees therewith.”

Thus, according to Borel, the definition of a given thing should consist as regards its construction or passive quality in something thoroughly known to us and true. Clavius, on the other hand, holds that it is a matter of indifference, whether the construction or passive quality be well known and true, or the reverse; so long as we do not assert, that our definition agrees with anything, before it has been proved.

I should prefer Borel’s opinion to that of Clavius. I know not which you would assent to, if to either. As these difficulties have occurred to me with regard to the nature of definition, which is reckoned among the cardinal points of demonstration, and as I cannot free my mind from them, I greatly desire, and earnestly beg you, when you have leisure and opportunity, to be kind enough to send me your opinion on the matter, and at the same time to tell me the distinction between axioms and definitions. Borel says that the difference is merely nominal, but I believe you decide otherwise.

Further, we cannot make up our minds about the third definition.1 I adduced to illustrate it, what my master said to me at the Hague,2 to wit, that a thing may be regarded in two ways, either as it is in itself, or as it is in relation to something else; as in the case of the intellect, for that can be regarded either under the head of thought, or as consisting in ideas. But we do not see the point of the distinction thus drawn. For it seems to us, that, if we rightly conceive thought, we must range it under the head of ideas; as, if all ideas were removed from it, we should destroy thought. As we find the illustration of the matter not sufficiently clear, the matter itself remains somewhat obscure, and we need further explanation.

Lastly, in the third note to the eighth proposition,3 the beginning runs thus:—“Hence it is plain that, although two attributes really distinct be conceived, that is, one without the aid of the other, we cannot therefore infer, that they constitute two entities or two different substances. For it belongs to the nature of substance, that each of its attributes should be conceived through itself, though all the attributes it possesses exist simultaneously in it.” Here our master seems to assume, that the nature of substance is so constituted, that it may have several attributes. But this doctrine has not yet been proved, unless you refer to the sixth definition, of absolutely infinite substance or God. Otherwise, if it be asserted that each substance has only one attribute, and I have two ideas of two attributes, I may rightly infer that, where there are two different attributes, there are also different substances. On this point also we beg you to give a further explanation. Besides I thank you very much for your writings communicated to me by P. Balling,4 which have greatly delighted me, especially your note on Proposition XIX.1 If I can do you any service here in anything that is within my power, I am at your dispesal. You have but to let me know. I have begun a course of anatomy, and am nearly half through with it; when it is finished, I shall begin a course of chemistry, and thus under your guidance I shall go through the whole of medicine. I leave off, and await your answer. Accept the greeting of

Your most devoted

S. J. de Vries.

Amsterdam, 24 Feb., 1663.

LETTER XXVII. (IX.)

Spinoza to Simon de Vries.

[Spinoza deprecates his correspondent’s jealousy of Albert Burgh; and answers that distinction must be made between different kinds of definitions. He explains his opinions more precisely.]

Respected Friend,—

I have received2 your long wished-for letter, for which, and for your affection towards me, I heartily thank you. Your long absence has been no less grievous to me than to you; yet in the meantime I rejoice that my trifling studies are of profit to you and our friends. For thus while you3 are away, I in my absence speak to you. You need not envy my fellow-lodger. There is no one who is more displeasing to me, nor against whom I have been more anxiously on my guard; and therefore I would have you and all my acquaintance warned not to communicate my opinions to him, except when he has come to maturer years. So far he is too childish and inconstant, and is fonder of novelty than of truth. But I hope, that in a few years he will amend these childish faults. Indeed I am almost sure of it, as far as I can judge from his nature. And so his temperament bids me like him.

As for the questions propounded in your club, which is wisely enough ordered, I see that your1 difficulties arise from not distinguishing between kinds of definition: that is, between a definition serving to explain a thing, of which the essence only is sought and in question, and a definition which is put forward only for purposes of inquiry. The former having a definite object ought to be true, the latter need not. For instance, if someone asks me for a description of Solomon’s temple, I am bound to give him a true description, unless I want to talk nonsense with him. But if I have constructed, in my mind, a temple which I desire to build, and infer from the description of it that I must buy such and such a site and so many thousand stones and other materials, will any sane person tell me that I have drawn a wrong conclusion because my definition is possibly untrue? or will anyone ask me to prove my definition? Such a person would simply be telling me, that I had not conceived that which I had conceived, or be requiring me to prove, that I had conceived that which I had conceived; in fact, evidently trifling. Hence a definition either explains a thing, in so far as it is external to the intellect, in which case it ought to be true and only to differ from a proposition or an axiom in being concerned merely with the essences of things, or the modifications of things, whereas the latter has a wider scope and extends also to eternal truths. Or else it explains a thing, as it is conceived or can be conceived by us; and then it differs from an axiom or proposition, inasmuch as it only requires to be conceived absolutely, and not like an axiom as true. Hence a bad definition is one which is not conceived. To explain my meaning, I will take Borel’s example—a man saying that two straight lines enclosing a space shall be called “figurals.” If the man means by a straight line the same as the rest of the world means by a curved line, his definition is good (for by the definition would be meant some such figure as (), or the like); so long as he does not afterwards mean a square or other kind of figure. But, if he attaches the ordinary meaning to the words straight line, the thing is evidently inconceivable, and therefore there is no definition. These considerations are plainly confused by Borel, to whose opinion you incline. I give another example, the one you cite at the end of your letter. If I say that each substance has only one attribute, this is an unsupported statement and needs proof. But, if I say that I mean by substance that which consists in only one attribute, the definition will be good, so long as entities consisting of several attributes are afterwards styled by some name other than substance. When you say that I do not prove, that substance (or being) may have several attributes, you do not perhaps pay attention to the proofs given. I adduced two:—First, “that nothing is plainer to us, than that every being may be conceived by us under some attribute, and that the more reality or essence a given being has, the more attributes may be attributed to it. Hence a being absolutely infinite must be defined, &c.” Secondly, and I think this is the stronger proof of the two, “the more attributes I assign to any being, the more am I compelled to assign to it existence;” in other words, the more I conceive it as true. The contrary would evidently result, if I were feigning a chimera or some such being.

Your remark, that you cannot conceive thought except as consisting in ideas, because, when ideas are removed, thought is annihilated, springs, I think, from the fact that while you, a thinking thing, do as you say, you abstract all your thoughts and conceptions. It is no marvel that, when you have abstracted all your thoughts and conceptions, you have nothing left for thinking with. On the general subject I think I have shown sufficiently clearly and plainly, that the intellect, although infinite, belongs to nature regarded as passive rather than nature regarded as active (ad naturam naturatam, non vero ad naturam naturantem).

However, I do not see how this helps towards understanding the third definition, nor what difficulty the latter presents. It runs, if I mistake not, as follows: “By substance I mean that, which is in itself and is conceived through itself; that is, of which the conception does not involve the conception of anything else. By attribute I mean the same thing, except that it is called attribute with respect to the understanding, which attributes to substance the particular nature aforesaid.” This definition, I repeat, explains with sufficient clearness what I wish to signify by substance or attribute. You desire, though there is no need, that I should illustrate by an example, how one and the same thing can be stamped with two names. In order not to seem miserly, I will give you two. First, I say that by Israel is meant the third patriarch; I mean the same by Jacob, the name Jacob being given, because the patriarch in question had caught hold of the heel of his brother. Secondly, by a colourless surface I mean a surface, which reflects all rays of light without altering them. I mean the same by a white surface, with this difference, that a surface is called white in reference to a man looking at it, &c.

LETTER XXVIII. (X.)

Spinoza to Simon de Vries.

[Spinoza, in answer to a letter from De Vries now lost, speaks of the experience necessary for proving a definition, and also of eternal truths.]

Respected Friend,—

You ask me if we have need of experience, in order to know whether the definition of a given attribute is true. To this I answer, that we never need experience, except in cases when the existence of the thing cannot be inferred from its definition, as, for instance, the existence of modes (which cannot be inferred from their definition); experience is not needed, when the existence of the things in question is not distinguished from their essence, and is therefore inferred from their definition. This can never be taught us by any experience, for experience does not teach us any essences of things; the utmost it can do is to set our mind thinking about definite essences only. Wherefore, when the existence of attributes does not differ from their essence, no experience is capable of attaining it for us.

To your further question, whether things and their modifications are eternal truths, I answer: Certainly. If you ask me, why I do not call them eternal truths, I answer, in order to distinguish them, in accordance with general usage, from those propositions, which do not make manifest any particular thing or modification of a thing; for example, nothing comes from nothing. These and such like propositions are, I repeat, called eternal truths simply, the meaning merely being, that they have no standpoint external to the mind, &c.

LETTER XXIX. (XII.)

Spinoza to L. M.1(Lewis Meyer).

Dearest Friend,—

I have received two letters from you, one dated Jan. 11, delivered to me by our friend, N. N., the other dated March 26, sent by some unknown friend to Leyden. They were both most welcome to me, especially as I gathered from them, that all goes well with you, and that you are often mindful of me. I also owe and repay you the warmest thanks for the courtesy and consideration, with which you have always been kind enough to treat me: I hope you will believe, that I am in no less degree devoted to you, as, when occasion offers, I will always endeavour to prove, as far as my poor powers will admit. As a first proof, I will do my best to answer the questions you ask in your letters. You request me to tell you, what I think about the infinite; I will most readily do so.

Everyone regards the question of the infinite as most difficult, if not insoluble, through not making a distinction between that which must be infinite from its very nature, or in virtue of its definition, and that which has no limits, not in virtue of its essence, but in virtue of its cause; and also through not distinguishing between that which is called infinite, because it has no limits, and that, of which the parts cannot be equalled or expressed by any number, though the greatest and least magnitude of the whole may be known; and, lastly, through not distinguishing between that, which can be understood but not imagined, and that which can also be imagined. If these distinctions, I repeat, had been attended to, inquirers would not have been overwhelmed with such a vast crowd of difficulties. They would then clearly have understood, what kind of infinite is indivisible and possesses no parts; and what kind, on the other hand, may be divided without involving a contradiction in terms. They would further have understood, what kind of infinite may, without solecism, be conceived greater than another infinite, and what kind cannot be so conceived. All this will plainly appear from what I am about to say.

However, I will first briefly explain the terms substance, mode, eternity, and duration.

The points to be noted concerning substance are these: First, that existence appertains to its essence; in other words, that solely from its essence and definition its existence follows. This, if I remember rightly, I have already proved to you by word of mouth, without the aid of any other propositions. Secondly, as a consequence of the above, that substance is not manifold, but single: there cannot be two of the same nature. Thirdly, every substance must be conceived as infinite.

The modifications of substance I call modes. Their definition, in so far as it is not identical with that of substance, cannot involve any existence. Hence, though they exist, we can conceive them as non-existent. From this it follows, that, when we are regarding only the essence of modes, and not the order of the whole of nature, we cannot conclude from their present existence, that they will exist or not exist in the future, or that they have existed or not existed in the past; whence it is abundantly clear, that we conceive the existence of substance as entirely different from the existence of modes. From this difference arises the distinction between eternity and duration. Duration is only applicable to the existence of modes; eternity is applicable to the existence of substance, that is, the infinite faculty of existence or being (infinitum existendi sive (invitâ Latinitate1 ) essendi fruitionem).

From what has been said it is quite clear that, when, as is most often the case, we are regarding only the essence of modes and not the order of nature, we may freely limit the existence and duration of modes without destroying the conception we have formed of them; we may conceive them as greater or less, or may divide them into parts. Eternity and substance, being only conceivable as infinite, cannot be thus treated without our conception of them being destroyed. Wherefore it is mere foolishness, or even insanity, to say that extended substance is made up of parts or bodies really distinct from one another. It is as though one should attempt by the aggregation and addition of many circles to make up a square, or a triangle, or something of totally different essence. Wherefore the whole heap of arguments, by which philosophers commonly endeavour to show that extended substance is finite, falls to the ground by its own weight. For all such persons suppose, that corporeal substance is made up of parts. In the same way, others, who have persuaded themselves that a line is made up of points, have been able to discover many arguments to show that a line is not infinitely divisible. If you ask, why we are by nature so prone to attempt to divide extended substance, I answer, that quantity is conceived by us in two ways, namely, by abstraction or superficially, as we imagine it by the aid of the senses, or as substance, which can only be accomplished through the understanding. So that, if we regard quantity as it exists in the imagination (and this is the more frequent and easy method), it will be found to be divisible, finite, composed of parts, and manifold. But, if we regard it as it is in the understanding, and the thing be conceived as it is in itself (which is very difficult), it will then, as I have sufficiently shown you before, be found to be infinite, indivisible, and single.

Again, from the fact that we can limit duration and quantity at our pleasure, when we conceive the latter abstractedly as apart from substance, and separate the former from the manner whereby it flows from things eternal, there arise time and measure; time for the purpose of limiting duration, measure for the purpose of limiting quantity, so that we may, as far as is possible, the more readily imagine them. Further, inasmuch as we separate the modifications of substance from substance itself, and reduce them to classes, so that we may, as far as is possible, the more readily imagine them, there arises number, whereby we limit them. Whence it is clearly to be seen, that measure, time, and number, are merely modes of thinking, or, rather, of imagining. It is not to be wondered at, therefore, that all, who have endeavoured to understand the course of nature by means of such notions, and without fully understanding even them, have entangled themselves so wondrously, that they have at last only been able to extricate themselves by breaking through every rule and admitting absurdities even of the grossest kind. For there are many things which cannot be conceived through the imagination but only through the understanding, for instance, substance, eternity, and the like; thus, if anyone tries to explain such things by means of conceptions which are mere aids to the imagination, he is simply assisting his imagination to run away with him.1 Nor can even the modes of substance ever be rightly understood, if we confuse them with entities of the kind mentioned, mere aids of the reason or imagination. In so doing we separate them from substance, and the mode of their derivation from eternity, without which they can never be rightly understood. To make the matter yet more clear, take the following example: when a man conceives of duration abstractedly, and, confusing it with time, begins to divide it into parts, he will never be able to understand how an hour, for instance, can elapse. For in order that an hour should elapse, it is necessary that its half should elapse first, and afterwards half of the remainder, and again half of the half of the remainder, and if you go on thus to infinity, subtracting the half of the residue, you will never be able to arrive at the end of the hour. Wherefore many, who are not accustomed to distinguish abstractions from realities, have ventured to assert that duration is made up of instants, and so in wishing to avoid Charybdis have fallen into Scylla. It is the same thing to make up duration out of instants, as it is to make number simply by adding up noughts.

Further, as it is evident from what has been said, that neither number, nor measure, nor time, being mere aids to the imagination, can be infinite (for, otherwise, number would not be number, nor measure measure, nor time time); it is hence abundantly evident, why many who confuse these three abstractions with realities, through being ignorant of the true nature of things, have actually denied the infinite.

The wretchedness of their reasoning may be judged by mathematicians, who have never allowed themselves to be delayed a moment by arguments of this sort, in the case of things which they clearly and distinctly perceive. For not only have they come across many things, which cannot be expressed by number (thus showing the inadequacy of number for determining all things); but also they have found many things, which cannot be equalled by any number, but surpass every possible number. But they infer hence, that such things surpass enumeration, not because of the multitude of their component parts, but because their nature cannot, without manifest contradiction, be expressed in terms of number. As, for instance, in the case of two circles, non-concentric, whereof one encloses the other, no number can express the inequalities of distance which exist between the two circles, nor all the variations which matter in motion in the intervening space may undergo. This conclusion is not based on the excessive size of the intervening space. However small a portion of it we take, the inequalities of this small portion will surpass all numerical expression. Nor, again, is the conclusion based on the fact, as in other cases, that we do not know the maximum and the minimum of the said space. It springs simply from the fact, that the nature of the space between two non-concentric circles cannot be expressed in number. Therefore, he who would assign a numerical equivalent for the inequalities in question, would be bound, at the same time, to bring about that a circle should not be a circle.

The same result would take place—to return to my subject—if one were to wish to determine all the motions undergone by matter up to the present, by reducing them and their duration to a certain number and time. This would be the same as an attempt to deprive corporeal substance, which we cannot conceive except as existent, of its modifications, and to bring about that it should not possess the nature which it does possess. All this I could clearly demonstrate here, together with many other points touched on in this letter, but I deem it superfluous.

From all that has been said, it is abundantly evident that certain things are in their nature infinite, and can by no means be conceived as finite; whereas there are other things, infinite in virtue of the cause from which they are derived, which can, when conceived abstractedly, be divided into parts, and regarded as finite. Lastly, there are some which are called infinite or, if you prefer, indefinite, because they cannot be expressed in number, which may yet be conceived as greater or less. It does not follow that such are equal, because they are alike incapable of numerical expression. This is plain enough, from the example given, and many others.

Lastly, I have put briefly before you the causes of error and confusion, which have arisen concerning the question of the infinite. I have, if I mistake not, so explained them that no question concerning the infinite remains untreated, or cannot readily be solved from what I have said; wherefore, I do not think it worth while to detain you longer on the matter.

But I should like it first to be observed here, that the later Peripatetics have, I think, misunderstood the proof given by the ancients who sought to demonstrate the existence of God. This, as I find it in a certain Jew named Rabbi Ghasdai, runs as follows:—“If there be an infinite series of causes, all things which are, are caused. But nothing which is caused can exist necessarily in virtue of its own nature. Therefore there is nothing in nature, to whose essence existence necessarily belongs. But this is absurd. Therefore the premise is absurd also.” Hence the force of the argument lies not in the impossibility of an actual infinite or an infinite series of causes; but only in the absurdity of the assumption that things, which do not necessarily exist by nature, are not conditioned for existence by a thing, which does by its own nature necessarily exist.

I would now pass on, for time presses, to your second letter: but I shall be able more conveniently to reply to its contents, when you are kind enough to pay me a visit. I therefore beg that you will come as soon as possible; the time for travelling is at hand. Enough. Farewell, and keep in remembrance Yours, &c.

Rhijnsburg, 20 April, 1663.

[2 ] Letter XXV.

[3 ]Potestas, as distinguished from potentia—the word just above translated power—means power delegated by a rightful superior, as here by God. So it is rendered here “sphere of power,” and in Tract. Pol. generally “authority.” It would not be proper to say that the “image of God” implied potestas.

[1 ] Surely this is a mistake for “excusable”—[Tr.]

[2 ] See Letter XXV. Oldenburg misunderstands Spinoza’s illustration, because he takes “canis” in the phrase, “qui ex morsu canis furit,” to be nominative instead of genitive; “a dog which goes mad from a bite,” instead of “he who goes mad from the bite of a dog.”

[1 ] For an account of Simon de Vries see Introduction, p. xiv. His letters are written in very indifferent Latin, which is, perhaps, one reason, why the present letter at least has been altered freely by the first editors.

[2 ] The version of this letter in Bruder’s and former editions is much altered by the omission of all mention of the club, and of the reference to Albert Burgh, and by the change throughout of the plural referring to the members of the club into the singular referring to the writer only. The genuine form here followed is to be found in Van Vloten’s Supplementum.

[1 ] This “fellow-lodger,” again mentioned in the next letter, is pretty certainly Albert Burgh, concerning whom see Introduction, p. xv, and Letters LXXIII. and LXXIV.

[2 ] Van Vloten infers that the members of the club were chiefly Jews.

[3 ] Peter Borel, born 1620, physician to the king of France, died 1689. He wrote several medical and philosophical works, and became in 1674 a member of the French Academy of Sciences.

[1 ] Andrew Jacquet, born at Antwerp 1611, was mathematical professor in that town, died 1660.

[2 ] Christopher Clavius, born at Bamberg 1537, was mathematical professor at Rome, died 1612.

[1 ] The third definition of the Ethics, as they now exist. See p. 45.

[2 ] Spinoza must, therefore, have visited the Hague before he lived there.

[3 ] In the Ethics as they now exist, “in I. x. note, towards the beginning,” to which reading the editors consequently altered the text, till the true reading was restored by Van Vloten.

[4 ] Peter Balling is the correspondent, to whom Spinoza wrote Letter XXX., which see. He translated into Dutch Spinoza’s Principia, as to which see Introduction, p. xv.

[1 ] There is no note to Ethics, I. xix. As there is nothing to show what proposition is intended, the old version suppressed the whole passage from “Besides I thank you” to “medicine.”

[2 ] The whole beginning of this letter, till after the mention of the club, is omitted in the editions before Van Vloten’s Supplementum, to make the letter agree with the altered version of Letter XXVI., to which it is an answer.

[3 ] “You” in these two places is plural, and refers to the club; so also the second “your” on the next page; elsewhere “you” and “your” refer to De Vries only.

[1 ] See Note 3 on previous page.

[1 ] See Introduction, pp. xv, xx.

[1 ] Spinoza apologizes here in the original for the use of the unclassical form “essendi,” being. The classical Latin verb of being is, as the ancients themselves admitted, defective in a most inconvenient degree.

[1 ] “Nihilo plus agit, quam si det operam ut sua imaginatione insaniat.” Mr. Pollock paraphrases, “It is like applying the intellectual tests of sanity and insanity to acts of pure imagination.”