and that of body; for it is as when in conceiving several things at once, one conceives something besides the number, viz.: res numeratas; and, moreover, there are not two multitudes, the one abstract-i. e., that of number; the other concrete-i. e., that of the things enumerated. Likewise one can say that it is not necessary to think of two extensions-the one abstract, of space, the other concrete, of body, the concrete existing as such only through the abstract. And as bodies pass from one part of space to another-i. e., change order among themselves-things also pass from one part of the order or of a number to the other, when, for example, the first becomes the second and the second the third, etc. In fact, time and space are only kinds of order, and in these orders the vacant place (which in relation to space is called vacuum), if there were any, would show the possibility only of that which is lacking together with its relation to the actual.

Ph. I am nevertheless very glad that you agree with me that matter does not change in volume. But you seem to go too far, Sir, in not recognizing two extensions, and you resemble the Cartesians, who do not distinguish space from matter. Now it seems to me that if a class is found who, not having these distinct ideas (of space and of solidity which fills it), blends them and makes of the two one only, we cannot see how these persons can converse with others. They are in that condition of a blind man with respect to another man who should speak to him of scarlet, whilst this blind man would believe that it resembles the sound of a trumpet.

Th. [But I hold at the same time that the ideas of extension and solidity, like that of scarlet-color, do not consist in a I know not what.' I distinguish extension and matter, contrary to the

1 Leibnitz's expression is un je ne say quoi." It seems to be equivalent to an indefinite somewhat which is the ultimate essence of things, and which is the cause of, and by differentiation becomes, the particular. Leibnitz, then, means to say that the ideas of extension and solidity are distinct. Cf. "Leibniz's New Essays Concerning the Human Understanding. A Critical Exposition." By John Dewey, Ph. D., Chicago: S. C. Griggs & Co., 1888, p. 134. As applied to personal beings, it seems to be equivalent to the "unconscious representations "-i. e., "the dark side of the soul-life," "the proper basis of Individuality." "Genius, disposition, feeling, are the terms by which a later time has designated what Leibnitz calls the je ne sais quoi, whereby every one is preformed by Nature to something Particular" ("Ganz wie bei dem blossen Monaden ihre individuelle Beschaffenheit in dem Momente der Schranke, der materia prima, lag, ganz so werden hier diese unbewussten Vorstellungen, d. h. wird die dunkle Seite des

view of the Cartesians. Still I do not believe that there are two extensions; and since those who dispute over the difference between extension and solidity are agreed on several truths upon this subject and have some distinct notions, they can find therein the means of extricating themselves from their disagreement; thus the assumed difference upon ideas ought not to serve as a pretext for eternal disputes, although I know that certain Cartesians, otherwise very able, are accustomed to intrench themselves in the ideas which they pretend to have. But if they would avail themselves of the means which I have before given for recognizing ideas true and false, and of which we shall speak also in the sequel, they would retire from a position which is not tenable.

CHAPTER V.

Of Simple Ideas which come by Different Senses.

Ph. The ideas, the perception of which comes to us from more than one sense, are those of Space, or Extension, or Figure, of Motion and Rest.

Th. [The ideas which are said to come from more than one sense, like those of space, figure, motion, rest, are rather from commonsense-i. e., from the mind itself, for they are ideas of pure understanding, but related to externality, and of which the senses make us conscious; they are also capable of definition and demonstration.]

CHAPTER VI.

Of Simple Ideas which come by Reflection.

Ph. The simple ideas which come by reflection are the ideas of the understanding and of the will [for we ourselves are conscious of them in reflecting upon ourselves.]

Th. [It is doubtful if all these ideas are simple, for it is clear, for example, that the idea of the will includes that of the understanding, and the idea of motion contains that of figure.

Seelenlebens, als der eigentliche Grund der Individualität bestimmt. Genius, Gemüth, Gefühl sind die Worte, mit denen eine spätere Zeit das bezeichnet hat, was Leibnitz das je ne sais quoi nennt, wodurch Jeder von Natur zu etwas Besonderem präformirt ist." Erdmann, “Grundriss d. Gesch. d. Philos.," 3te. Auflage 2te. Bd. s. 161. Berlin, 1878.) Cf. also Leibnitz, "Nouveaux Essais," Preface, pp. 46 sq. Gerhardt; 197, a, Erdmann; Book II, Ch. I, § 15. Th., sq., and Erdmann's exposition of the same, op. cit., s. 160, 161. Also Prof. Dewey's most excellent work cited above.-TR.

CHAPTER VII.

Of Ideas which come by Sensation and Reflection.

§ 1. Ph. There are some simple ideas which make themselves perceived in the mind by all the avenues of sensation and by reflection also-viz.: pleasure, pain, power, existence, unity.

Th. [It seems that the senses cannot convince us of the existence of sensible things without the aid of the reason. Thus I should think that the idea' of existence comes from reflection. That of power also and of unity come from the same source, and are of a wholly different nature from the perceptions of pleasure and pain.]

CHAPTER VIII.

Other Considerations upon Simple Ideas.

§ 2. Ph. What shall we say of ideas of privative qualities? It seems to me that the ideas of rest, darkness, and cold are as positive as those of motion, light, and heat. However, in proposing these privations as the causes of privative ideas I follow the common view; but in the main it will be difficult to determine whether there is really any idea which arises from a privative cause until it has been determined whether rest any more than motion is a privation.

Th. [I have never believed that you could have reason to doubt the privative nature of rest. It suffices it to deny motion in the body, but it does not suffice for motion to deny rest, and it is necessary to add something more to determine the degree of motion, since it receives materially more or less, while all rest is equal. It is another thing when you speak of the cause of rest, which should be positive in the second matter or mass. I should furthermore regard the idea itself of rest as privative-i. e., that it consists only in negation. It is true that the act of denial is positive.]

§ 9. Ph. The qualities of things being the faculties they have of producing in us perception of ideas, it is well to distinguish these qualities. They are primary and secondary. Extension, solidity, figure, number, mobility are the original qualities inseparable from body which I call primary. § 10. But I call second

1 French is "la consideration de l'existence."

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ary qualities the faculties or powers of bodies to produce certain sensations in us, or certain effects in other bodies, as the fire, for example, produces some effect in the wax when melting it.

Th. [I think you can say that when the power is intelligible, and can be distinctly explained, it should be reckoned among the primary qualities; but when it is only sensed and gives only a confused idea, it should be put among the secondary qualities.]

§ 11. Ph. These primary qualities show how bodies act upon one another. Now, bodies act only by impulse, at least so far as we can conceive the process, for it is impossible to understand how bodies can act upon what they do not touch, which is equivalent to imagining that they can act where they are not.

Th. [I am also of the opinion that bodies act only by impulse. However, there is some difficulty in proving what I have just heard; for attraction is not always without contact, and you can touch and draw without any visible impulse, as I have shown above in speaking of hardness. In the case of the atoms of Epicurus, the one part pushed would draw the other with it, and would touch it in putting it in motion without impulse. And in the case of attraction between contiguous things you cannot say that the one which draws with itself acts where it is not. This reason would militate only against attractions from a distance, as would be the case in reference to what are called vires centripetas, advanced by some scholars.]

§ 13. Ph. Now, certain particles, striking our organs in a certain way, cause in us certain sensations of colors or tastes or other secondary qualities which have the power of producing these sensations. And it is no more difficult to conceive that God can attach such ideas (as that of heat) to motions, with which these have no resemblance, than it is difficult to conceive that he has attached the idea of pain to the motion of a piece of iron which divides our flesh; which motion the pain in no manner resembles.

Th. [It is not necessary to suppose that ideas like those of color or of pain are arbitrary and without relation or natural connection with their causes; it is not the custom of God to act with so little order and reason. I should rather say that there is a kind of resemblance, not complete and, so to speak, in terminis, but expressive, or a kind of orderly relation, as an ellipse, and even a parabola or hyperbola resemble in some sense a circle of which

they are a projection upon a plane, since there is a certain exact and natural relation between what is projected and the projection which is made, each point of the one corresponding by a certain relation to each point of the other. This the Cartesians do not sufficiently consider, and for once you have deferred to them more than has been customary with you, and without reason for so doing.]

§ 15. Ph. I tell you how it appears to me, and the appearances are that the ideas of the primary qualities of bodies resemble these qualities, but the ideas produced in us by the secondary qualities resemble them in no way.

Th. [I have just shown how there is resemblance or exact relation in respect to the secondary as well as the primary qualities. It is certainly reasonable that the effect correspond to its cause; and how assert the contrary, since you know distinctly neither the sensation of blue (for example) nor the motions which produce it? It is true that pain does not resemble the motion of a pin, but it may very well resemble the motions which this pin causes in our body, and represent these motions in the soul, as I have no doubt it does. It is also on that account that we say that the pain is in our body and not that it is in the pin; but we say that the light is the fire, because there are in the fire motions which are not distinctly sensible apart from it, but whose confusion or conjunction becomes sensible, and is represented to us by the idea of light.

§ 21. Ph. But if the relation between the object and the sensation be natural, how can it be, as we notice in fact, that the same water may appear warm to one hand and cold to the other? which shows that the heat is no more in the water than the pain is in the pin.

Th. [That proves all the more that heat is not a quality of sense or power of making itself felt absolutely all at once, but that it is relative to the suitable organs; for a motion proper in the hand may be there mixed and change in appearance. Light, furthermore, does not make itself evident to badly constituted eyes, and when they are themselves filled with a great light, a less is not sensed by them. Even the primary qualities (according to our classification)-for example, unity and number-may not appear as they should; for, as Descartes has already stated, a globe touched by the fingers in a certain way appears double, and mir