ourselves to affirmations and provided we avoid negative statements which limit the designs of God. All those who see. the admirable structure of ani- mals find themselves led to recognize the wisdom of the author of things and I advise those who have DISCOURSE ON METAPHYSICS. 35 any sentiment of piety and indeed of true philos- ophy to hold aloof from the expressions of certain pretentious minds who instead of saying that eyes were made for seeing, say that we see because we find ourselves having eyes. When one seriously holds such opinions which hand everything over to material necessity or to a kind of chance (although either alternative ought to appear ridiculous to those who understand what we have explained above) it is difficult to recognize an intelligent author of nature. The effect should correspond to its cause and indeed it is best known through the recognition of its cause, so that it is reasonable to introduce a sovereign intelligence ordering things, and in place of making use of the wisdom of this sov- ereign being, to employ only the properties of matter to explain phenomena. As if in order to account for the capture of an important place by a prince, the historian should say it was because the particles of powder in the cannon having been touched by a spark of fire expanded with a rapidity capable of pushing a hard solid body against the walls of the place, while the little particles which composed the brass of the cannon were so well interlaced that they did not separate under this impact,—as if he should account for it in this way instead of making us see how the foresight of the conqueror brought him to choose the time and the proper means and how his ability surmounted all obstacles.
XX. A noteworthy disquisition in Plato's Phaedo against the philosophers who were too materialistic.
This reminds me of a fine disquisition by Socrates in Plato’s Phaedo, which agrees perfectly with my 36 LEIBNIZ.
Opinion on this subject and seems to have been uttered expressly for our too materialistic philos- ophers. This agreement has led me to a desire to translate it although it is a little long. Perhaps this example will give some of us an incentive to share in many of the other beautiful and well bal- anced thoughts which are found in the writings of this famous author. * XXI. If the mechanical laws depended upon Geome- try alone without metaphysical influences, the phenom- ena would be very different from what they are.
Now since the wisdom of God has always been recognized in the detail of the mechanical struc- tures of certain particular bodies, it should also be shown in the general economy of the world and in the constitution of the laws of nature. This is so true that even in the laws of motion in general, the plans of this wisdom have been noticed. For if bodies were only extended masses, and motion were only a change of place, and if everything ought to be and could be deduced by geometric necessity from these two definitions alone, it would follow, as I have shown elsewhere, that the smallest body on contact with a very large one at rest would impart to it its own velocity, yet without losing any of the velocity that' it'had. ‘A ‘quantity ‘of other rules wholly contrary to the formation of a system would also have to be admitted. But the decree of the divine wisdom in preserving always the same force and the same total direction has provided for a * There is a gap here in the MS., intended for the passage from Plato, the translation of which Leibniz did not supply.— T7ans.
DISCOURSE ON METAPHYSICS. a7 system. I find indeed that many of the effects of nature can be accounted for in a twofold way, that is to say by a consideration of efficient causes, and again independently by a consideration of final causes. An example of the latter is God’s decree to always carry out his plan by the easiest and most determined way. I have shown this elsewhere in accounting for the catoptric and dioptric laws, and I will speak more at length about it in what follows.
XXII. Reconciliation of the two methods of explana- tion, the one using final causes, and the other efficient causes, thus satisfying both those who explain nature mechanically and those who have recourse to incorpo- real natures.
It is worth while to make the preceding remark in order to reconcile those who hope to explain mechanically the formation of the first tissue of an animal and all the interrelation of the parts, with those who account for the same structure by refer- ring to final causes. - Both explanations are good; both are useful not only for the admiring of the work of a great artificer, but also for the discovery of: useful facts in physics and medicine. And writers who take these diverse routes should not speak ill of each other. For 1 see that those who attempt to explain beauty by the divine anatomy ridicule those who imagine that the apparently fortuitous flow of certain liquids has been able to produce such a beautiful variety and that they regard them as over- bold and irreverent. These others on the contrary treat the former as simple and superstitious, and compare them to those ancients who regarded the physicists as impious when they maintained that 38 LEIBNIZ.
not Jupiter thundered but some material which is found in the clouds. The best plan would be to join the two ways of thinking. To use a practical comparison, we recognize and praise the ability of a workman not only when we show what designs he had in making the parts of his machine, but also when we explain the instruments which he employed in making each part, above all if these instruments are simple and ingeniously contrived. God is also a workman able enough to produce a machine still a thousand times more ingenious than is our body, by employing only certain quite simple liquids pur- posely composed in such a way that ordinary laws of nature alone are required to develop them so as to produce such a marvellous effect. But it is-also true that this development would not take place if God were not the author of nature. Yet I find that the method of efficient causes, which goes much deeper and is in a measure more immediate and @ priort, is also more difficult when we come to details, and I think that our philosophers are still very frequently far removed from making the most of this method. The method of final causes, however, is easier and can be frequently employed to find out important and useful truths which we should have to seek for a long time, if we were confined to that other more physical method of which anatomy is able to furnish many examples. It seems to me that Snellius, who was the first discoverer of the laws of refraction would have waited a long time before finding them if he had wished to seek out first how light was formed. But he apparently followed that method which the ancients employed for Catoptrics, that is, the method of final causes. Because, while DISCOURSE ON METAPHYSICS. 39 seeking for the easiest way in which to conduct a ray of light from one given point to another given point by reflection from a given plane (supposing that that was the design of nature) they discovered the equality of the angles of incidence and reflec- tion, as can be seen from a little treatise by Helio- dorus of Larissa and also elsewhere. This principle Mons. Snellius, I believe, and afterwards independ- ently of him, M. Fermat, applied most ingeniously te refraction. For since the rays while in the same media always maintain the same proportion of sines, which in turn corresponds to the resistance of the media, it appears that they follow the eastest way, or at least that way which is the most determinate for passing from a given point in one medium toa given point in another medium. That demonstra- tion of this same theorem which M. Descartes has given, using efficient causes, is much less satisfac- tory. At least we have grounds to think that he would never have found the principle by that means if he had not learned in Holland of the discovery of Snellius.
XXIII. Returning to immaterial substances we ex- plain how God acts upon the understanding of spirits and ask whether one always keeps the idea of what he thinks about.
] have thought it well to insist a little upon final causes, upon incorporeal natures and upon an intelligent cause with respect to bodies so as to show the use of these conceptions in physics and in mathematics. This for two reasons, first to purge from mechanical philosophy the impiety that ts imputed to it, second, to elevate to nobler lines of 40 is LEIBNIZ.
thought the thinking of our philosophers who -incline to materialistic considerations alone. Now, however, it will be well to return from corporeal substances to the consideration of immaterial natures and particularly of spirits, and to speak of the methods which God uses to enlighten them and to act upon them. Although we must not forget that there are here at the same time certain laws of nature in regard to which I can speak more amply elsewhere. It will be enough for now to touch upon ideas and to inquire if we see everything in God and how God is our light. First of all it will be in place to remark that the wrong use of ideas occasions. many errors. For when one reasons in regard to anything, he imagines that he has an idea of it and this is the foundation upon which certain philosophers, ancient and modern, have constructed a demonstration of God that is extremely imperfect. It must be, they say, that I have an idea of God, or of a perfect being, since I think of him and we can- not think without having ideas; now the idea of this being includes all perfections and since exist- ence is one of these perfections, it follows that he exists. But I reply, inasmuch as we often think of impossible chimeras, for example of the highest degree of swiftness, of the greatest number, of the meeting of the conchoid with its base or determinant, such reasoning is not sufficient. It is therefore in this sense that we can say that there are true and false ideas according as the thing which is in ques- tion ts possible or not. And it is when he is assured of the possibility of a thing, that one can boast of having an idea of it. Therefore, the aforesaid argu- ment proves that God exists, if he is possible. This DISCOURSE ON METAPHYSICS, 41 is in fact an excellent privilege of the divine nature, to have need only of a possibility Or an essence in order to actually exist, and it is just this ween Is called ens a se.
XXIV. What clear and obscure, distinct and con- fused, adequate and inadequate, intuitive and assumed knowledge is, and the definition of nominal, real, causal and essential.
In order to understand better the nature of ideas it is necessary to touch somewhat upon the various kinds of knowledge. WhenIam able to recognize a thing among others, without being able to say in what its differences or characteristics consist, the knowl- edge is confused. Sometimes indeed we may know clearly, that is without being in the slightest doubt, that a poem or a picture is well or badly done because there is in it an “I know not what’? which satisfies or shocks us. Such knowledge is not yet distinct. It is when I am able to explain the pecu- liarities which a thing has, that the knowledge is called distinct. Such is the knowledge of an assayer who discerns the true gold from the false by means of certain proofs or marks which make up the definition of gold. But distinct knowledge has degrees, because ordinarily the conceptions which enter into the definitions will themselves have need of definition, and are only known confusedly. When at length everything which enters into a definition or into distinct knowledge is known dis- tinctly, even back to the primitive conception, I | call that knowledge adequate. When my mind | understands at once and distinctly all the primitive ingredients of a conception, then we have intuitive 42 LEIBNIZ.
knowledge. This is extremely rare as most human knowledge is only confused or indeed assumed. It is well also to distinguish nominal from real defini- tion. I call a definition nominal when there is doubt whether an exact conception of it is pos- sible; as for instance, when I say that an endless screw is a line in three dimensional space whose parts are congruent or fall one upon another. Now although this is one of the reciprocal proper- ties of an endless screw, he who did not know from elsewhere what an endless screw was could doubt if such a line were possible, because the other lines whose ends are congruent (there are only two: the circumference of a circle and the straight line) are plane figures, that is to say they can be described in plano. This instance enables us to see that any reciprocal property can serve as a nominal defint- tion, but when the property brings us to see the possibility of a thing it makes the definition real, and as long as one has only a nominal definition he cannot be sure of the consequences which he draws, because if it conceals a contradiction or an impos- sibility he would be able to draw the opposite con- clusions. That is why truths do not depend upon names and are not arbitrary, as some of our new philosophers think. There is also a considerable difference among real definitions, for when the pos- sibility proves itself only by experience, as in the definition of quicksilver, whose possibility we know because such a body, which is both an extremely heavy fluid and quite volatile, actually exists, the definition is merely real and nothing more. If, however, the proof of the possibility is @ prtort, the definition is not only real but also causal as for DISCOURSE ON METAPHYSICS. 43 instance when it contains the possible generation of a thing. Finally when the definition, without assuming anything which requires a proof @ priorz of its possibility, carries the analysis clear to the primitive conception, the definition is perfect or essential, XXV. In what cases knowledge is added to mere con- templation of the idea.
Now it is manifest that we have no idea of a con- ception when it is impossible. And in case the knowl- edge, where we have the idea of it, is only assumed, we do not visualize it because such a conception is known only in like manner as conceptions internally impossible. And if it be in fact possible, it is not by this kind of knowledge that we learn its possi- bility. For instance, when I am thinking of a thousand or of a chiliagon, I frequently do it with- out contemplating the idea. Even if I say a thou- sand is ten times a hundred, I frequently do not trouble to think what ten and a hundred are, because I assume that ] know, and I do not con- sider it necessary to stop just at present to conceive of them. Therefore it may well happen, as it in fact does happen often enough, that I am mistaken in regard to a conception which I assume that I understand, although it is an impossible truth or at least is incompatible with others with which I join it, and whether I am mistaken or not, this way of assuming our knowledge remains the same. It ts, then, only when our knowledge is clear in regard to confused conceptions, and when it is intuitive in regard to those which are distinct, that we see its entire idea.
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XXVI. Ideas are all stored up within us. Plato’s doctrine of reminiscence.
In order to see clearly what an idea is, we must guard ourselves against a misunderstanding. Many regard the idea as the form or the differentiation of our thinking, and according to this opinion we have the idea in our mind, in so far as we are thinking of it, and each separate time that we think of it anew we have another idea although similar to the preceding one. Some, however, take the idea as the immediate object of thought, or as a permanent form which remains even when we are no longer contemplating it. Asa matter of fact our soul has the power of representing to itself any form or nature whenever the occasion comes for thinking about it, and I think that this activity of our soul is, so far as it expresses some nature, form or essence, properly the idea of the thing. This is in us, and is always in us, whether we are thinking of it or no. (Our soul expresses God and the uni- verse and all essences as well as all existences.) This position is in accord with my principles that naturally nothing enters into our minds from outside.
It is a bad habit we have of thinking as though our minds receive certain messengers, as it were, or as if they had doors or windows. We have in our minds all those forms for all periods of time because the mind at every moment expresses all its future thoughts and already thinks confusedly of all that of which it will ever think distinctly. Nothing can be taught us of which we have not already in our minds the idea. This idea ts as it were the material out of which the thought will form itself. This is what Plato has excellently brought DISCOURSE ON METAPHYSICS, 45 out in his doctrine of reminiscence, a doctrine which contains a great deal of truth, provided that it is properly understood and purged of the error of pre-existence, and provided that one does not con- ceive of the soul as having already known and thought at some other time what it learns and thinks now. Plato has also confirmed his position by a beautiful experiment. He introduces a small boy, whom he leads by short steps, to extremely difficult truths of geometry bearing on incommen- surables, all this without teaching the boy anything, merely drawing out replies by a well arranged se- ries of questions. This shows that the soul virtually knows those things, and néeds only to be reminded (animadverted) to recognize the truths. Conse- quently it possesses at least the idea upon which “those truths depend. We may say even that it already possesses those truths, if we consider them as the relations of the ideas.
XXVII. In what respect our souls can be compared - to blank tablets and how conceptions are derived from the senses.
Aristotle preferred to compare our souls to blank tablets prepared for writing, and he maintained that nothing is in the understanding which does not come through the senses. This position is in accord with the popular conceptions as Aristotle’s positions usually are. Plato thinks more pro- foundly. Such tenets or practicologies are never- theless allowable in ordinary use somewhat in the same way as those who accept the Copernican theory still continue to speak of the rising and set- ting of the sun. I find indeed that these usages can 46 LEIBNIZ.
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be given a real meaning containing no error, quite in the same way as I have already pointed out that we may truly say particular substances act upon one another. In this same sense we may say that knowledge is recetved from without through the medium of the senses because certain exterior things contain or express more particularly the causes which determine us to certain thoughts. Because in the ordinary uses of life we attribute to the soul only that which belongs to it most manifestly and particularly, and there is no advantage in going further. When, however, we are dealing with the exactness of metaphysical truths, it is important to recognize the powers and independence of the soul which extend infinitely further than is commonly supposed. In order, therefore, to avoid misunder- standings it would be well to choose separate terms for the two. These expressions which are in the soul whether one ts conceiving of them or not may be called ideas, while those which one conceives of or constructs may be called conceptions, conceptus. But whatever terms are used, it is always false to say that all our conceptions come from the so-called external senses, because those conceptions which I have of myself and of my thoughts, and con- sequently of being, of substance, of action, of identity, and of many others came from an inner experience.
XXVIII. The only immediate object of our percep- tions which exists outside of us is God, and in him alone is our light.
In the strictly metaphysical sense no external cause acts upon us excepting God alone, and he ts DISCOURSE ON METAPHYSICS. 47 in immediate relation with us only by virtue of our continual dependence upon him. Whence it fol- lows that there is absolutely no other external object which comes into contact with our souls and directly excites perceptions in us. We have in our souls ideas of everything, only because of the con- tinual action of God upon us, that is to say, because every effect expresses its cause and therefore the essences of our souls are certain expressions, imita- tions or images of the divine essence, divine thought and divine will, including all the ideas which are there contained. We may say, therefore, that God is for us the only immediate external object, and that we see things through him. For example, when we see the sun or the stars, it is God who gives to us and preserves in us the ideas and whenever our senses are affected according to his own laws in a certain manner, it is he, who by his continual concurrence, determines our thinking. God is the sun and the light of souls, /wsmen clluminans omnem hominem venientem in hunc mundum, although this is not the current conception. I think I have already remarked that during the scholastic period many believed God to be the light of the soul, intellectus agens anime rationalis, following in this the Holy Scriptures and the fathers who were always more Platonic than Aristotelian in their mode of thinking. The Averroists misused this conception, but others, among whom were several mystic theologians, and William of Saint Amour, also I think, understood this conception in a manner which assured the dignity of God and was able to raise the soul to a knowledge of its welfare.
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XXIX. Yet we think directly by means of our own ideas and not through God’s.
Nevertheless I cannot approve of the sosition of certain able philosophers who seem to hold that our ideas themselves are in God and not at all in us. I think that in taking this position they have neither sufficiently considered the nature of sub- stance, which we have just explained, nor the entire extension and independence of the soul which includes all that happens to it, and expresses God, and with him all possible and actual beings in the same way that an effect expresses its cause. It is © indeed inconceivable that the soul should think using the ideas of something else. The soul when it thinks of anything must be affected effectively in a certain manner, and it must needs have in itself in advance not only the passive capacity of being thus affected, a capacity already wholly determined, but it must have besides an active power by virtue of which it has always had in its nature the marks of the future production of this thought, and the disposition to produce it at its proper time. All of this shows that the soul already includes the idea which is comprised in any particular thought.
XXX. How God inclines our souls without necessitat- ing them; that there are no grounds for complaint; that we must not ask why Judas sinned because this free act is contained in his concept, the only question being why Judas the sinner is admitted to existence, preferably to other possible persons; concerning the original imperfec- tion or limitation before the fall and concerning the different degrees of grace.
Regarding the action of God upon the uae DISCOURSE ON METAPHYSICS. 49 will there are many quite different considerations which it would take too long to investigate here. Nevertheless the following is what can be said in general. God in co-operating with ordinary actions only follows the laws which he has established, that 1s to say, he contirually preserves and pro- duces our being so that the ideas come to us spon- taneously or with freedom in that order which the concept of our individual substance carries with itself. In this concept they can be foreseen for all eternity...Furthermore, by virtue of, the decree which God has made that the will shall always seek the apparent good in certain particular respects (in regard to which this apparent good always has in it something of reality expressing or imitating God’s will), he, without at all necessitating our choice, determines it by that which appears most desirable. For absolutely speaking, our will as contrasted with necessity, is in a state of indiffer- ence, being able to act otherwise, or wholly to sus- pend its action, either alternative being and remain- ing possible. It therefore devolves upon the soul to be on guard against appearances, by means of a firm will, to reflect and to refuse to act or decide in certain circumstances, except after mature delibera- tion. It is, however, true and has been assured from all eternity that certain souls will not employ their power upon certain occasions.
But who could do more than God has done, and can such a soul complain of anything except itself? All these complaints after the deed are unjust, inas- much as they would have been unjust before the deed. Would this soul a little before committing the sin have had the right to complain of God as 50 LEIBNIZ.