On Blood and Lymph: Spinoza's Letter 32, summary

by Corry Shores
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[The following summarizes the first part of the letter. After which, I include the text of the letter in full.]

Spinoza responds to Oldenburg's inquiry into his "grounds of our belief that each part of Nature accords with the whole and coheres with other parts" (192b).

Spinoza responds that he is incapable of knowing exactly how it is so, for that requires knowing "the whole of Nature and all its parts." However, he will account for why he holds this belief.

By coherence of parts, Spinoza means "that the laws or nature of one part adapts itself to the laws or nature of another part in such wise that there is the least possible opposition between them" (192d). He considers

things as parts of a whole to the extent that their natures adapt themselves to one another so that they are in the closest possible agreement. In so far as they are different from one another, to that extent each one forms in our mind a separate idea and is therefore considered as a whole, not a part. (192-193)

Spinoza offers for an example "the motions of particles of lymph, chyle, etc." They

adapt themselves to one another in accordance with size and shape so as to be fully in agreement with one another and to form all together one single fluid, to that extent only are the chyle, lymph, etc. regarded as parts of the blood. But in so far as we conceive the particles of lymph as different from the particles of chyle in respect of shape and motion, to that extent we regard them each as a whole, not a part. (193a)

Spinoza then has us imagine a tiny worm swimming in our blood, which is a) capable of distinguishing the blood particles (chyle, lymph, etc.) and b) able to observe how "each particle, on colliding with another, either rebounds or communicates some degree of its motion, and so forth" (193b). This worm exists in our blood just as we do in "our part of the universe:" it regards each part of the blood as a whole rather than as a part, and it could not possibly know how the blood's overall nature controls its parts and compels them to mutually adapt to each other "as the overall nature of the blood requires, so as to agree with one another in a definite way." (193bc)

If no external force "communicates new motions to the blood," then the blood would remain as it is and "its particles would undergo no changes other than those which can be conceived as resulting from the existing relation between the motion of the blood and of the lymph, chyle, etc. Thus the blood would always have to be regarded as a whole, and not a part." (193c)

However, there are in fact numerous causes that modify the blood so that the it undergoes motions and changes not caused by its inherent parts. These new motions result "not solely from the reciprocal relation of its particles but from the relation between the motion of the blood on the one hand and external causes on the other. From this perspective the blood is accounted as a part, not as a whole" (194a).

We should consider all the bodies of Nature this way, "for all bodies are surrounded by others and are reciprocally determined to exist and to act in a fixed and determinate way, the same ratio of motion to rest being preserved in them taken all together, that is, in the universe as a whole" (194a.b).

Thus all modified bodies "must be considered as a part of the whole universe, and as agreeing with the whole and cohering with the other parts" (194b).

But unlike blood, the universe is not limited; it is absolutely infinite, so its infinite potency controls its parts in infinite ways, thereby compelling them to undergo infinite variations. Yet, we must conceive each part as intimately bound up with the whole of substance. (194c)

So the human body is a part of Nature, so too the human mind, because Nature bears an infinite power of thinking that contains "the whole of Nature ideally, and whose thoughts proceed in the same manner as does Nature, which is in fact the object of its thought" (194-195).

The human mind has this same power of thinking: it does not understand the whole of nature, because the human mind is finite, so it apprehends the human body only. But the human body is a part of infinite substance, so the human mind is part of "an infinite intellect." (195b)

The letter's text:

LETTER XV. (XXXII.)

SPINOZA TO OLDENBURG.

[Spinoza writes to his friend concerning the reasons which lead us to believe, that "every part of nature agrees with the whole, and is associated with all other parts." He also makes a few remarks about Huyghens.]

Distinguished Sir,—For the encouragement to pursue my speculations given me by yourself and the distinguished R. Boyle, I return you my best thanks. I proceed as far as my slender abilities will allow me, with full confidence in your aid and kindness. When you ask me my opinion on the question raised concerning our knowledge of the means, whereby each part of nature agrees with its whole, and the manner in which it is associated with the remaining parts, I presume you are asking for the reasons which induce us to believe, that each part of nature agrees with its whole, and is associated with the remaining parts. For as to the means whereby the parts are really associated, and each part agrees with its whole, I told you in my former letter that I am in ignorance. To answer such a question, we should have to know the whole of nature and its several parts. I will therefore endeavour to show the reason, which led me to make the statement; but I will premise that I do not attribute to nature either beauty or deformity, order or confusion. Only in relation to our imagination can things be called beautiful or deformed, ordered or confused.

By the association of parts, then, I merely mean that the laws or nature of one part adapt themselves to the laws or nature of another part, so as to cause the least possible inconsistency. As to the whole and the parts, I mean that a given number of things are parts of a whole, in so far as the nature of each of them is adapted to the nature of the rest, so that they all, as far as possible, agree together. On the other hand, in so far as they do not agree, each of them forms, in our mind, a separate idea, and is to that

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extent considered as a whole, not as a part. For instance, when the parts of lymph, chyle, &c., combine, according to the proportion of the figure and size of each, so as to evidently unite, and form one fluid, the chyle, lymph, &c., considered under this aspect, are part of the blood; but, in so far as we consider the particles of lymph as differing in figure and size from the particles of chyle, we shall consider each of the two as a whole, not as a part.

Let us imagine, with your permission, a little worm, living in the blood, able to distinguish by sight the particles of blood, lymph, &c., and to reflect on the manner in which each particle, on meeting with another particle, either is repulsed, or communicates a portion of its own motion. This little worm would live in the blood, in the same way as we live in a part of the universe, and would consider each particle of blood, not as a part, but as a whole. He would be unable to determine, how all the parts are modified by the general nature of blood, and are compelled by it to adapt themselves, so as to stand in a fixed relation to one another. For, if we imagine that there are no causes external to the blood, which could communicate fresh movements to it, nor any space beyond the blood, nor any bodies whereto the particles of blood could communicate their motion, it is certain that the blood would always remain in the same state, and its particles would undergo no modifications, save those which may be conceived as arising from the relations of motion existing between the lymph, the chyle, &c. The blood would then always have to be considered as a whole, not as a part. But, as there exist, as a matter of fact, very many causes which modify, in a given manner, the nature of the blood, and are, in turn, modified thereby, it follows that other motions and other relations arise in the blood, springing not from the mutual relations of its parts only, but from the mutual relations between the blood as a whole and external causes. Thus the blood comes to be regarded as a part, not as a whole. So much for the whole and the part.

All natural bodies can and ought to be considered in the same way as we have here considered the blood, for all bodies are surrounded by others, and are mutually determined to exist and operate in a fixed and definite proportion,

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while the relations between motion and rest in the sum total of them, that is, in the whole universe, remain unchanged. Hence it follows that each body, in so far as it exists as modified in a particular manner, must be considered as a part of the whole universe, as agreeing with the whole, and associated with the remaining parts. As the nature of the universe is not limited, like the nature of blood, but is absolutely infinite, its parts are by this nature of infinite power infinitely modified, and compelled to undergo infinite variations. But, in respect to substance, I conceive that each part has a more close union with its whole. For, as I said in my first letter 1 (addressed to you while I was still at Rhijnsburg), substance being infinite in its nature, 2 it follows, as I endeavoured to show, that each part belongs to the nature of substance, and, without it, can neither be nor be conceived.

You see, therefore, how and why I think that the human body is a part of nature. As regards the human mind, I believe that it also is a part of nature; for I maintain that there exists in nature an infinite power of thinking, which, in so far as it is infinite, contains subjectively the whole of nature, and its thoughts proceed in the same manner as nature—that is, in the sphere of ideas. 3 Further, I take the human mind to be identical with this said power, not in so far as it is infinite, and perceives the whole of nature, but in so far as it is finite, and perceives only the human body; in this manner, I maintain that the human mind is a part of an infinite understanding.

variations. But, in respect to substance, I conceive that each part has a more close union with its whole. For, as I said in my first letter 1 (addressed to you while I was still at Rhijnsburg), substance being infinite in its nature, 2 it follows, as I endeavoured to show, that each part belongs to the nature of substance, and, without it, can neither be nor be conceived.

You see, therefore, how and why I think that the human body is a part of nature. As regards the human mind, I believe that it also is a part of nature; for I maintain that there exists in nature an infinite power of thinking, which, in so far as it is infinite, contains subjectively the whole of nature, and its thoughts proceed in the same manner as nature—that is, in the sphere of ideas. 3 Further, I take the human mind to be identical with this said power, not in so far as it is infinite, and perceives the whole of nature, but in so far as it is finite, and perceives only the human body; in this manner, I maintain that the human mind is a part of an infinite understanding.

But to explain, and accurately prove, all these and kindred questions, would take too long; and I do not think you expect as much of me at present. I am afraid that I may have mistaken your meaning, and given an answer to a different question from that which you asked. Please inform me on this point.

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You write in your last letter, that I hinted that nearly all the Cartesian laws of motion are false. What I said was, if I remember rightly, that Huyghens thinks so; I myself do not impeach any of the laws except the sixth, concerning which I think Huyghens is also in error. I asked you at the same time to communicate to me the experiment made according to that hypothesis in your Royal Society; as you have not replied, I infer that you are not at liberty to do so. The above-mentioned Huyghens is entirely occupied in polishing lenses. He has fitted up for the purpose a handsome workshop, in which he can also construct moulds. What will be the result I know not, nor, to speak the truth, do I greatly care. Experience has sufficiently taught me, that the free hand is better and more sure than any machine for polishing spherical moulds. I can tell you nothing certain as yet about the success of the clocks or the date of Huyghens' journey to France.

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Footnotes

292:1 Letter II.

292:2 Ethics, I. viii.

292:3 I have given what seems to be the meaning of this passage. The text is very obscure: "Nempe quia statuo dare etiam in natura potentiam infinitam cogitandi, quæ, quatenus infinita, in se continet totam naturam objective et cujus cogitationes procedunt ac natura ejus, nimirum idearum." M. Saisset in his French translation says here, "In this place I rather interpret than translate Spinoza, as his thought does not seem to me completely expressed."—[Tr.]

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Summary based on:

Spinoza. The Letters. Transl Samuel Shirley. Cambridge: Hackett Publishing Company, Inc., 1995.

Text reproduction from R. H. M. Elwes translation, available online at:

http://www.sacred-texts.com/phi/spinoza/corr/corr12.htm