1 Leibnitz here refers to the Tabula logica, in which Porphyry, 233-304, and after him the Scholastic logicians, such as Lambert of Auxerre, c. 1250, Petrus Hispanus, c. 122(i-1277, Raimund Lulli, 1234-1315, the Pseudo-Thomas, and Johannes Majoris Scotus, 1478-1540, sought, in connection with the live pre- dicables, to arrange in strict logical subordination by the process of dicho tomic or bifurcate division, all genera and species from the highest genera to the lowest species, between which is found the scale of subordinate notions which are at the same time both genus and species. This Tabula loyica was called by the later commentators, who added the diagram illustrating it, not found in Porphyry, the arbor Porphyriana or the arbor praedicamentalis, and the line of subordination from the highest genus to the lowest species was called the linea praedicamentalis or praedicabilis, or the ordo praedicamentalis. Cf. Porphyry, Eio-aywyij chap. 2, 1 b. 40 sq. (in Aristotle, ed. Berl. Acad., Vol. 4, p. 1); 'Ef>jyijo-i«, f. 18 b., Paris, 1543, 4to; Prantl, Gesch. d. Lor/ik im Abend- lande, Leipzig, 1855-1870, Vol. 1, pp. (527-8, note 41, <>33-4, note 67, Vol. 3, pp. 28, note 14: " Praedicamentnm autern nihil aliud est, quain ordinatio praedicabilium in linea praedicabile seciindnm sub et supra et a latere et in linea recta,...unde ilia tota ordinatio, qnae est inter genus generalissimum et speciem specialissimam et genera subalterna et differentias collaterales, voca- tur unum praedicamentum, sicut patet in arbore Porphyrii in tractatu Prae- dicabilium." (Lambert of Auxerre, Summa logicae, Paris, MS., Cod. tiorbonn. 1707), 4<>, note 1(58, 151, note 42, 252, note 315, c/. n. 311, Vol. 4, p. 249, note 434; also, Jevons, Elementary Lessons in Logic, p. 103 sg. — TR.
CH. iv] ON HUMAN UNDERSTANDING 323 species to the highest genus. The reason is that the lowest species being only a simple idea, nothing can be taken from it; for example, nothing can be taken from the ideas of white and red in order to retain the common appearance in which they agree. For this reason, they are included with yellow and others, under the genus or the name, color. And when men wish to frame a still more general term, comprising, also, sounds, tastes, and tangible qualities, they avail themselves of the general term, quality, in the sense ordinarily given it to distinguish these qualities of extension, number, motion, pleas ure, and pain, which act upon the mind and introduce into it their ideas by more than one sense.
Tk. [I have something more to say upon this remark. I hope that here and elsewhere you will do me the justice, sir, to believe that this is not from a spirit of contradiction, and that the subject seems to demand it. It is not an advan tage that the ideas of sensible qualities have so little subordina tion and are capable of so few subdivisions; for it arises only from the fact that we know little of them. But the fact itself that all colors have the common property of being seen by the eyes, of all passing into bodies from which one or more of them reappear, and of being reflected from the polished surfaces of bodies which do not allow them to pass, shows us that something can be taken from the ideas we have of them. Colors may indeed be divided with good reason into extremes (one of which is positive, viz. white; and the other privative, viz. black); and into means, which are called colors,1 however, in a particular sense, and which spring from light by refrac tion; which furthermore may be subdivided into those of the convex side, and those of the concave side of the broken ray. And these divisions and subdivisions are of not a little conse quence.]
Ph. But how can you find genera in simple ideas?
Th. [As they are simple only in appearance, they are accompanied by circumstances which are bound up with them, 1 Gerhardt reads: "et en moyens qu'on appelle encor couleurs dans un sens particulier et qui naissent de la lumiere par la refraction; qu'on peut encor," etc.; Erdmann and Jacques read: " et en moyens qu'on appelle encore sous-diviser," etc.; i.e. and into means which you are further called upon to subdivide, etc. — TR.
324 LEIBNITZ'S CRITIQUE OF LOCKE [UK. in although this bond is not understood by us, and these circum stances furnish somewhat that is explicable and susceptible of analysis, which gives also some hope that hereafter the reasons of these phenomena may be discovered. Thus it happens that there is a kind of pleonasm in our perceptions of sensible qualities, as well as sensible masses; and this pleonasm is, that we have more than one notion of the same subject. Gold may be denned nominally in several ways; you may say that it is the heaviest of our bodies, that it is the most malle able, that it is a fusible body which resists the cupel and aqua fortis, etc. Each of these marks is good and is sufficient for the recognition of gold, at least provisionally and in the present state of our bodies, until a heavier body is found, as some chemists maintain is the case in their philosopher's stone, or until that Luna fixa l is shown, which is a metal said to have the color of silver, and almost all the other qualities of gold, and which Chevalier Boyle 2 seems to say he has produced. Thus you may say that in matters which we know only empirically, all our definitions are merely provisional, as I believe I have already remarked above. It is then true that we do not know demonstratively whether a color may not pos- 1 Cf. Fratris Basilii Valentini Benedictiner Ordens Chymische Schrift., Hamburg, 1700, Pt. I., p. 272: " Wenn das Gold seiner Anima aucli verlustig wird / giebt es ein weiss Corpus und einen fixen weissen Gold-Leib / der von den suchenden Studenten / und von den Jiingern der Kunst cine Luna Jixa getaufft und genannt wird; " Pt. II., p. 381, Scliluss-Reden Fr. Basilii Valentini, Tract. 1, Sectio iii., De Magneta vulgi, § 3: "Mitdem Magnet und Antimonio wird auch eine Luna fixa gemacht / welche alsdann durch das Oleum, Murtis & Veneris gradirt [sic], und zu Gold gemacht wird: Jedoch kan mans mit Antimonio und Eisen auch verrichtcn." Martin Ruland, Lexicon alchemias, Francofurti, 1612, p. 308: "Luna compacta est argentum fixum vel aurum album: Silber fix oder weiss Gold." Robert Boyle, Works, ed. Birch, 5 vols., fol.: London, 1744, Vol. 1, p. 215; 2d ed., 6 vols., 4to: London, 1772, Vol. 1, p.
2 Robert Boyle, 1G27-1G91, a distinguished natural philosopher and chemist, the discoverer of the law of the compressibility of gases, which, confirmed by its independent discovery by Mariotte in 1(!76, has since been known as " Boyle and Mariotte's Law." He was one of the founders of the Royal Society of London, and by his will established the " Boyle Lectures." Leibnitz often refers to him, cf. Neiv Essays, Preface, ante, p. 47. — The title of Boyle's work there referred to is, Of Absolute Rest in Bodies, Works, ed., Birch, 6 vols., 4to, London, 1772, Vol. 1, pp. 443-457, in which he opposes the doctrine with convincing reasons; — Bk. IV., chap. 12, § 13, Th., infra, p. 526; Gerhardt, Leibniz philos. Schrift., 7, 342; Dutens, Leibnit op. om., 5, 98; 6, 107; Leib nitz's estimate of his experiments, 6, 318; Eulogy, 6, Pt. II., 217. — TR.
en. v] ON HUMAN UNDERSTANDING 325 sibly be produced by reflection alone without refraction, and whether the colors we have hitherto noticed in the concavity of the angle of ordinary refraction are not found in the con vexity of a kind of refraction hitherto unknown, and vice versa. Thus the simple idea of blue would be stripped of the genus which we have assigned it in our experiences. But it is well to stop at the blue we have and at the circumstances attending it. And it is something that they furnish us the means of making genera and species.]
§ 17. Ph. But what say you of the remark that has been made that simple ideas, since they are taken from the existence of things, are nowise arbitrary, while those of the mixed modes are wholly so, and those of substances to some extent?
Th. [1 believe that the arbitrary quality is found only in the words, and not at all in the ideas. For they express only possibilities. Thus, if there had never been a parricide, and if all the legislators had been as cautious as Solon in speaking of it, parricide would be a possible crime, and its idea would be real. For ideas are in God from all eternity; and indeed they are in us before we actually think of them, as" I have shown in our previous conversations.1 If any one wishes to take them as the actual thoughts of men, it is per mitted him to do so, but he will oppose himself without reason to the accepted language.
CHAPTER V OF THE NAMES OF MIXED MODES AND RELATIONS §§ 2, 3, seq. Ph. But does not the mind form mixed ideas by bringing together simple ideas as suits its purpose, without the need of a real model; while simple ideas arise for it i Of. New Essays, Preface, ante, p. 42, sq., Bk. I., chap. 1, § 1, sq., ante, p. 70, sq., where Leibnitz develops more fully the thought repeated here. Leibnitz assumes that ideas — the pure truths of reason— exist in man, and come into consciousness by the self-development of the spirit. These ideas contain in themselves the potential representation of all possible reality, the realization of which is directly proportional to the measure of man's self- development. In God this realization is complete, since in his thought all real possibility is always actually represented. — TR.
326 LEIBNITZ'S CRITIQUE OF LOCKE [UK. in without choice, through the real existence of things? Is not the mixed idea often seen before the existing thing?
Tli. If you take the ideas as actual thoughts, you are right. But I do not see that it is necessary to apply your distinction to that which concerns the form itself, or the possibility of these thoughts, and yet this is the question in the ideal world which is distinguished from the existing world. The real existence of beings which are not at all necessary is a matter of fact or of history; but the knowledge of possibilities and necessities (for necessary is that the opposite of which is not at all possible) constitutes the demonstrative sciences.1] Ph. But is there more connection between the ideas of killing and of man than between the ideas of killing and of a sheep? Is parricide composed of more connected notions than infanticide? And is it more natural that what the English call stabbing, i.e., murder by a thrust, or by striking with the point, which is a greater wrong with them than killing by striking with the edge of the sword, should have deserved a name and an idea which is not accorded, for example, to the act of killing a sheep, or of killing a man by cutting?
Th. [If the question concerns only possibilities, all these ideas are equally natural. Those who have seen sheep killed have had an idea of this act in thought, although they have not deigned to give it their attention.2 Why, then, limit our selves to names, when the question concerns ideas themselves, and why occupy ourselves with the worth of the ideas of the mixed modes, when the question concerns these ideas in general?]
§ 8. Ph. Men form arbitrarily different kinds of mixed modes, so that words are found in one language for which there are no corresponding words in another. There are no words in other languages corresponding to the word Versura 3 1 Cf. New Essays, Preface, ante, p. 43. — TR.
2 Erdmann reads: " quoiqu'ils ne lui aient point donne de nom et ne 1'aient point daigne de lenr attention; " Jacques reads, after "daigne," " honorer," otherwise like Erdmann. The rendering then is: although they have not given it a name, nor have they vouchsafed (to honor — Jacques) it (with) their attention. — TR.
3 "Versura," literally "a turning round," means, in classical usage, "the borrowing of money to pay a debt," a process which resulted simply in changing one's creditor, not in extinguishing the obligation. Cf. Cicero, Epist.
en. v] ON HUMAN UNDERSTANDING 327 used among the Romans, nor to Corban,1 used by the Jews. We boldly translate the Latin words /torn, pes, and libra, by hour, foot, and pound; but the ideas of the Romans were very different from ours.
Tli. I see that many things which we discussed when the question was that of ideas themselves and their kinds, come back now, under cover of the names of these ideas. The statement is true as regards the names and the customs of men, but it changes nothing in the sciences and in the nature of things. It is true that he who would write a universal grammar would do well to pass from the essence of languages to their existence, and compare the grammars of many lan guages. In like manner, an author who should write a univer sal jurisprudence drawn from reason, would do well to unite with it the parallel laws and customs of peoples, which would be of service not only in practical life, but also in his reflec tions, and would give him occasion to consider many points which would otherwise escape him. But in science itself, apart from its history or existence, it is of no consequence whether people are or are not conformed to the dictates of reason.]
§ 9. Ph. The doubtful signification of the word species makes the statement that the species of mixed modes are made by the understanding offensive to some people. But I leave it to others to consider who fixes the limits of each sort or species, for these two words are for me wholly synonymous.
ad Atticum, 5, 15, 2; Tacitus, Ann., 0, 1C. As a proverb, the word means "to get out of one difficulty by getting into another." Cf. Terence, Phormio, 5, 2, 15; Lactantius, 2, 8, 24. — TR.
1 "Corban," Hebrew JS "1J3, N.T. Kopfiav, i.e. SSipov, originally an offering to God of any kind, particularly in fulfilment of a vow. The original use was in course of time altered by the traditionalists, and the offerer of the gift interdicted from using it for himself, or giving it to others. The " corban " furnished a ready means to any one who wished to relieve himself from any inconvenient obligation, as of assisting his parents in poverty or distress; he simply brought his gift to the temple and offered it to God, saying, "Let it be corban," and departed free, as he said, from any further responsibility in the matter. It was this utter perversion of the spirit of the law, with its resultant positive wrong-doing, that Christ so severely rebuked. Cf. Mark 7:11-13; Matt. 15:5, 0; and H. A. W. Meyer, Krit. Ercr/. Knmmentar «. d. N.T., fith ed., Gottingen, 187<>— I., 2 [Vol. 2], p. 104; I., 1 [Vol. 1], p. 333; Smith's Diet, of the Bible, ed. Hackett and Abbot, New York, 1877, Vol. 1, 328 LEIBNITZ'S CRITIQUE OF LOCKE [BK. in Th. [The nature of things ordinarily fixes the limits of species; for example, of man and beast, of cut and thrust. I admit, however, that there are some notions in which the limit is truly arbitrary; for example, the question of determining a foot, for, the straight line being uniform and indefinite, nature indicates therein no limits. There are also essences, vague and imperfect, into which opinion enters; as when you ask how little hair must be allowed a man in order that he be not bald. This was one of the sophisms of the ancients, when one pressed upon his adversary: Dum cadat elusus ratione mentis acervi.1 But the true answer is that nature has not determined this notion, and that the opinion has its share therein that there are some persons regarding whom it may be questioned whether they are bald or not, and that there are some doubtful persons who will pass as bald with some and not with others, as you remarked that a horse which will be considered small in Holland, will pass as a large one in the country of the Gauls. There is indeed something of this nature in simple ideas, for I just observed that the final limits of colors are doubtful. There are also essences truly half-nominal, in which the name enters into the definition of the thing; for example, the degree or quality of doctor, chevalier, ambassador, king, is recognized when a person has acquired the recognized right to avail him self of this name. And a foreign minister, however complete his power and however extended his train, will not pass as an ambassador unless his letter of credence gives him the name. Biit these essences and ideas are vague, doubtful, arbi trary, nominal, in a sense a little different from those which you have mentioned.]
§ 10. Ph. But it seems that the name often conserves the essences of the mixed modes which you think are not arbitrary; for example, without the name triumph, we should have but little idea of what took place among the Romans upon that occasion.
Tli. [I agree that the name serves to call attention to things and to conserve the memory and the actual knowledge of them; CH. v] ON HUMAN UNDERSTANDING 329 but that accomplishes nothing as regards the point in question, nor does it render the essences nominal; and I do not under stand why you gentlemen absolutely require that the essences themselves should depend upon the choice of names. It would have been desirable that your distinguished author, instead of insisting upon that, had preferred to enter into a much more detailed account of ideas and of modes, and to have set them in order and developed the varieties. 1 would have followed him on this road with pleasure and with profit. For he would doubtless have given us much light.]
§ 12. Ph. When we speak of a horse, or of iron, we regard them as the things which furnish us the original patterns of our ideas; but when we speak of mixed modes or, at least, of the most important of these modes, which are moral entities, — for example, justice, gratitude, — we consider their original modes as existing in the mind. Therefore we say the notion of justice, of temperance; but we do not say the notion of a horse, of a stone.
Th. [The patterns of the ideas of the one are as real as those of the ideas of the other. The qualities of the mind are not less real than those of the body. It is true you do not see justice as you see a horse, but you understand it no less, or rather you understand it better; it is no less in acts than directness or obliqueness is in motions, whether you consider it or not. And to show you that men are of my opinion, and men, indeed, the most capable and most experi enced in human affairs, I have only to avail myself of the authority of the Roman jurisconsults, followed by all others, who call these mixed modes or these moral entities, things, and in particular, incorporeal things. For servitudes,1 for ex ample (like that of the passage through the ground of one's neighbor), are with them res incorporates, in which there is a property which may be acquired by long use, and may be possessed and reclaimed. As for the word notion, many clever people have considered it as large as that of idea; Latin usage 1 Cf. Sandars, Institutes of Justinian, Lib. II., Tit. III., p. 118, 8th ed., London: Longmans, Green, & Co., 1H88; Poste, Gaius, Elements of Roman Law, Bk. II., 29, 31, pp. Kio-fi,:id ed., Oxford, 18<K); Mommsen, Digest, Lib. VIII., 1, Vol. 1, p. 250, Berlin: Weidmann, 1870; Hadley, In trod, to Roman Law, pp. 158-101, 180-19(i, New York, D. Appletou & Co., 18*1. — Tu.
330 LEIBNITZ'S CRITIQUE OF LOCKE [nK. in is not opposed thereto, nor do I know whether that of the English or the French is contrary to it.1] § 15. Ph. It is further to be remarked that men learn the names before the ideas of the mixed modes; the name showing them that this idea deserves to be observed.
Tli. [This remark is a good one, although it is true that now-a-days children, with the aid of nomenclators, ordinarily learn the names not only of the modes, but also of substances, before the things, and indeed rather the names of substances than of the modes; for it is a defect in these same nomen clators that they employ nouns only, and not verbs; not con sidering that verbs, although signifying the modes, are more essential in conversation than the majority of nouns, which indicate particular substances.2] CHAPTER VI OF THE NAMES OF SUBSTANCES § 1. Ph. The genera and species of substances, as of other beings, are only sorts. For example, suns are a sort of stars, i.e. they are fixed stars, for it is not without reason that we think each fixed star would make itself known as a sun to a person placed at a proper distance. § 2. ISTow that which limits each sort is its essence. It is known either by its interior structure, or by external indications which make us recognize it and call it by a certain name: and thus it is that we may recognize the clock of Straslmrg either as the clock- maker who made it, or as a spectator who sees its effects.
Tli. [If this is your statement, I have nothing to oppose to it.]
1 Cf. Neio Essm/K, Bk. II., chap. 22, § 2, Th. mite, p. 222; Discoiirs de Meta- physique, lf>8(i, § 29, Gerhardt, 4, 452. For the meaning and use of these terms: in Latin, idea, notio, conceptus or conccptio; in French, idee, notion, concep tion; in German, Idee, Vorstelhtny, Bee/riff; in English, idea, notion, con ception or concept, which varies according to the period in the history of thought in which they are employed, and according to the theory of knowledge implicitly or consciously held hy the author using them, cf. Krauth-Flemming, Vocab.ofthe Philos. Sciences, ed. of 1877, sub roc. — Tn.
2 " For," as Schaarschmidt says, " the activity is first perceived, and hy its means the substance recognized and formulated." — TR.
CH. vi] ON HUMAN UNDERSTANDING 331 Ph. I express myself in a way suited not at all to renew our discussions. But I add that the essence is related only to sorts, and that nothing is essential to individuals. An accident or a disease may change my color or shape; a fever or a fall may take away my reason or memory; apoplexy may leave me neither feeling, understanding, nor life. If you ask me if it is essential to me to have reason, I reply: no.
Th. [I think that there is something essential to individuals and more than you suppose. It is essential to substances to act, to created substances to suffer, to minds to think, to bodies to have extension and motion. That is, there are some sorts or species to which an individual cannot (naturally at least) cease to belong, when it has once been of their number, what ever revolutions may happen in nature. But there are some sorts or species, which are accidental (I admit) to the indi viduals, which may cease to belong to them. Thus you may cease to be healthy, beautiful, wise, and indeed to be visible and palpable, but you cannot cease to have life and organs and perception. I have stated sufficiently, above, why it appears to men that life and thought sometimes cease, although they cease not to endure and to have their effects.]
§ 8. Ph. Many individuals ranked under a common name, considered as belonging to one species only, have nevertheless very different qualities depending upon their real (particular) constitutions. This is easily observed by all those who ex amine natural bodies; and chemists often are convinced of it by sad experience, when they vainly seek in one portion of antimony, sulphur, and vitriol for the qualities which they have found in other portions of these minerals.
Th. [Xo statement has more truth, and I could myself even furnish intelligence concerning it. Books have also been written expressly de infido experimentorum chymicorum successu. But the error consists in taking these bodies as similar or uniform, while they are more mixed than we suppose; for in dissimilar bodies we are not surprised to remark differences between individuals, and physicians do not know how much the tem peraments and natural dispositions of human bodies differ. In a word, we shall never find the final logical species, as I have already remarked above, and two real or complete indi- 332 LEIBNITZ'S CRITIQUE OF LOCKE [HK. in viduals of one and the same species are never perfectly alike.1] Ph. We do not notice all these differences, because we do not know the little parts, nor consequently the interior struct ure of things. Thus we do not avail ourselves of them in order to determine the sorts or species of things, and if we wished to do so by means of these essences, or by what the schools call substantial forms, we should be like a blind man who desired to arrange bodies according to colors. § 11, We do not indeed know the essences of spirits, we know not how to form distinct specific ideas of angels, although we well know that there must be many kinds of spirits. Thus it seems that in our ideas we put no difference between God and the spirits by any number of simple ideas, save that we attribute infinity to God.
Th. [There is, however, another difference in my system between God and created spirits, viz. that in my view all created spirits must have bodies, just as our soul has one.2] § 12. Ph. I think at least that there is this analogy between bodies and spirits, that as there is 110 gap in the varieties of the corporeal world, so there will be no less variety in intelli gent creatures. Commencing from ourselves and proceeding even to the lowest things, a descent is made by very small 1 Cf. New Essays, Preface, ante, p. 51, Bk. II., chap. 27, ante, p. 238 sq.; De ipsa natura, § 13, Gerhardt, 4, 512, Erdmann, 158, b, Jacques, 1, 464 (in French), trans. Duncan, Philos. Works of Leibnitz, 122, 123; Monadoloyie, § 9, G. 6, 608, E. 705, J. 2, 392, trans. D. 219, ~F. H. Hedge, "Jour. Spec. Philos.," 1, 129; 4th letter to Clarke, §§ 4 sq., G. 1, 372, E. 755, b, J. 2, 432, trans. D. 247, 5th letter to Clarke, § 21, G. 7, 393, E. 765, J. 2, 449, trans. D. 258. This is the principle of the identity of indiscernibles, principium identitatis indiscerni- bilium — i.e. that " things qualitatively (indistinguishable are absolutely identi cal." According to Leibnitz, there are no such things, there being in the universe no two objects perfectly alike; though abstractly possible, they are inconsistent with the order of things, and with the divine wisdom, which admits nothing therein without reason. Cf.;ilso Kant's development and criticism of Leibnitz's principles in his Dilucidatio nova, 1755. Werke, ed. Rosenkranz & Schubert, Leipzig, 1838-42, Vol. 1, p. 1; ed. Hartenstein, Leipzig, 1867-68, Vol. 1, p. 365, Krit. d. r. Vernunft, V. d. Amphibolic d. Reflerions- bef/nfe, ed. R. & S. 2, 214, ed. H. 3, 225, 4th ed., J. H. v. Kirchmann, Leipzig, 1877, p. 268 sq., E. Caird, The frit. Philos. of Immanvel Kant, 1, 106 sq., 445 sq., 500 sq., New York, Macmillan & Co., 1889: Ueberweg, Hist,, of Philos., 2 Cf. Ncio Essays, Preface, ante, p. 52, Bk. II., chap. 1, § 12, Th. ante, p. 113, chap. 15, § 4, Th. ante, p. 159, and note. — TR.
en. vj] ON HUMAN UNDERSTANDING 333