TRANSLATION EDITED BY THOMAS JEFFERSON
In proportion as I advance in the digestion of these elements, I am incessantly obliged to return to objects, of which I have already treated. At the commencement of the grammar it was necessary to recall the attention of the reader to the analysis of the judgment, to render still more precise the idea of that intellectual operation, and of its results, and to repeat several of the effects already recognized in the signs, and several of their relations, with the nature of the ideas which they represent.
At the commencement of the volume which treats more especially of logic, I of necessity looked back on the ancient history of the science, to show, that true logic is absolutely the same science with that of the formation, the expression, and combination of our ideas; that is to say, that which has been since called Ideology, general grammar, or analysis of the understanding; and to show that my two first volumes are but the restoration, more or less fortunate, of the two first parts of the ancient logics, and the supplement of that which has always been wanting to these very important preliminaries. I have moreover been under the necessity of insisting also on the explication of the idea of existence, and on that of the reality of our perceptions, and of their necessary concordance with the reality of the beings which cause them, when they are all legitimately deduced from the first and direct impressions, which these beings make on us.
At present I find myself, in like manner, constrained to speak again of the conclusions of this logic, before advancing further, and not to apply my theory of the causes of certitude and error, to the study of the will and its effects, without having given it some new developments. The reader ought to pardon these frequent retrospects; for they arise almost necessarily from the nature of the subject, from the manner in which it has been treated hitherto, and from the necessity we are under, of anticipating a crowd of objections, when we wish to render a new opinion acceptable.
Let me be permitted then to mention here again, that I have reduced the whole science of logic to the observation of two facts, which result manifestly from the scrupulous examination of our intellectual operations. The first is, that our perceptions being every thing for us, we are perfectly, completely, and necessarily sure of all that we actually feel. The second, which is but a consequence of that, is that none of our judgments, taken separately, can be erroneous, since, for the very reason that we see one idea in another, it must be actually there; but that their falsity, when it takes place, is purely relative to all the anterior judgments, which we permit to subsist, and consists in this, that we believe the idea, in which we see a new element, to be the same we have always had under the same sign, while it is really different, since the new element we actually see there is incompatible with some of those which we have previously seen there. So that, to avoid contradiction, it would be necessary either to take away the former, or not to admit the latter.
After having established these two principles, or rather these two facts, I have given some elucidations, I have met in advance some objections, I have shown that these two objections are equally true, whatever be the nature of our ideas, and whatever the use we make of them; and hence I have concluded, that all the rules whatsoever which have been prescribed for the form of our reasonings, to assure us of their justice, are absolutely useless and illusory; and that our sole and only means of preserving ourselves from error, is to assure ourselves well that we comprehend the idea of which we judge, and if it be doubtful, to make the most complete enumeration possible of the elements which compose it, and principally of those which may either implicitly contain or exclude that whose admission or exclusion is in question. It is here that, without more details, I have terminated my treatise on logic, which consequently finishes almost at the point at which all the others commence. This ought so to be, as I meant to speak only of the science; while other logicians, neglecting the science almost entirely, have occupied themselves only with the art. I confess my belief, that my labour is more useful than theirs; because, in every matter, it is always very difficult, from premature consequences, to remount to the principles which ought to have served as their foundation. Whereas, when we have well established the first truths, it is easy to deduce the consequences which flow from them. Yet this second operation is important also, and as a subject is not completely treated of, but when it is executed, I will present, before proceeding further, summarily, but methodically, the series of practical maxims, which result from my method of considering our means of knowledge. The use I shall afterwards make of these same means, in the study of the will and its effects, will be an example of the manner in which these rules are applied in all our researches.
We know our existence only by the impressions we experience, and that of beings other than ourselves, but by the impressions which they cause on us.
In like manner, as all our propositions may be reduced to the form of enunciative propositions, because at bottom they all express a judgment, so all our enunciative propositions may afterwards be always reduced to some one of these: I think, I feel, or I perceive, that such a thing is in such a manner, or that such a being produces such an effect; propositions of which we are ourselves the subject, because in fact we are always the subject of all our judgments, since they never express but the impression which we experience.
From hence it follows: 1st. That our perceptions are all of them always such as we feel them, and are not susceptible of any error, taken each separately, and in itself.
2dly. That if in the different combinations, we make of them, we add to them nothing which is not primitively comprised in them, implicitly or explicitly, they are always conformable to the existence of the beings which cause them, since that existence is not known to us but by them, and consists for us only in those perceptions.
3dly. That we know nothing but relatively to ourselves, and to our means of receiving perceptions.
4thly. That these perceptions are every thing for us; that we know nothing ever but our perceptions; that they are the only things truly real for us, and that the reality which we recognize in the beings that cause them is only secondary, and consists only in the permanent power of always causing the same impressions under the same circumstances, whether on ourselves, or on other sensible beings, who give us an account of them (also by the impressions which they cause in us) when we have become able to hold communication with them by signs.
Since our perceptions are all of them always such as we feel them, when we perceive one idea in another, it is actually and really there, from the very circumstance of our perceiving it there: hence no one of our judgments taken separately and detached, is false. It has always and necessarily the certitude which belongs inevitably to each of our actual perceptions.
None of our judgments then can be false, but relatively to anterior judgments, and that suffices to render them false relatively to the existence of beings, the causes of our impressions, if these anterior judgments were just, relatively to that existence.
When we see in an idea, or a perception, an element incompatible with those which it included before, this idea is different from what it was, for, such as it was, it excluded this new element which we see there; and, such as it is, it excludes those which are incompatible with it.
That it may then be the same idea which it was before, we must exclude from it the element which we see there at present, or if those which are repugnant to it, are misplaced in this idea, they must themselves be excluded from it; that is to say, it must be rendered such as it was, when they were erroneously admitted into it, which is to restore it again to the same state in which it was, before it was changed by a false judgment, without our perceiving it.
When we form a judgment of an idea, when we see in it a new element, one of these four things must necessarily happen: Either the judgment which we now form is consequent to a just idea, in which case it is just; and the idea without changing its nature has only developed and extended itself.
Or it is inconsequent to a just idea, in which case it is false; and the idea is changed, and is become false.
Or it is consequent to an idea already false, then it is false, but the idea is not changed; it is when it has become false previously, that it has changed in relation to what it was primitively.
Or it is inconsequent to a false idea, then it may be just or false; but never certain, for the idea is changed. But it may have become just, such as it was originally, or false, in a manner different from the preceding.
Remark always, that an idea infected with false elements, and consequently meriting the name of false, taken in mass, may also contain many true elements. We may form then, in consequence of these true elements, just judgments, and then they will be completely true; as we may also form from them false judgments, which shall be completely false; but these judgments will not be formed from that idea, inasmuch as it is false, and in consequence of that which it has of falsity; they ought therefore to be considered as formed from a true idea, and enter into what we have said of these.
This is what most frequently happens to us, so few compound ideas have we which are perfectly pure, and without mixture of imperfection. Perhaps we have none. Perhaps it would suffice for us to have one alone, to render all our others the same, by the sole force of their relations and combinations, proximate or remote.
Thus all our perceptions are originally just and true, and error is only introduced to them at the moment when we admit an element which is opposed to them. That is to say, which denaturalises and changes them, without our perceiving it.
This would never happen to us, if we had always present to the mind, that which the idea comports, of which we judge. Thus all our errors really come from this: that we represent the idea imperfectly to ourselves.
What precedes not appertaining to any circumstance peculiar to any one of our perceptions rather than to another, agrees generally with all.
Hence it follows, 1st. That our manner of proceeding is the same for our ideas of every kind.
2dly. That all our errors originate from the basis of our ideas, and not from the form of our reasonings.
3dly. That all the rules which can be prescribed for the forms of these reasonings, can contribute nothing to avoid error; or at least can contribute to it but accidentally.
We have then no other effectual means of avoiding error, but to assure ourselves well of the comprehension of the idea of which we judge, that is to say, of the elements of which it is composed.
That is not possible, unless we commence by well determining the extension of this idea, for it contains many elements in certain degrees of its extension, which it does not in others, that is to say, it is not exactly similar to itself, it is not rigorously the same idea in their different degrees of extension.
This general and only method embraces several others, and first that of studying with care the object, or objects, from which the idea in question emanates, and afterwards that of guarding ourselves with the same care from the affections, passions, prejudices, dispositions, habits and manners of being, by which the idea could be altered.
These two precautions are necessary, the first to assemble, as far as possible, all the elements which really appertain to the idea in question, the second to separate from it in like manner all those which are foreign to it, and which might mingle themselves with it, and alter it, without our perceiving it.
After these two necessary preliminaries, if we are still in doubt as to the judgment we are to form, the most useful expedient of which we can avail ourselves, is to make an enumeration the most complete possible of the elements composing the idea, which is the subject of the judgment, and principally of those which have relation to the idea which we propose to attribute to it, that is to say, to the attribute of the contemplated judgment.
The effect of this operation is to recall to ourselves, or to those whom we wish to convince of the truth or falsity of a proposition, the elements of the subject which implicitly comprehend the proposed attribute, or which on the contrary may exclude it.
It is the object which the logicians propose to attain by what they call definitions; but in my opinion they fall into several errors relatively to definitions, and they greatly mistake their effects and properties.
1st. They believe that there are definitions of words, and definitions of things, while in truth there are none but definitions of ideas. When I explain the sense of a word, I do nothing but explain the idea which I have when I pronounce that word, and when I explain what a being is, I still do nothing but explain the idea I have of that being, and which I express when I pronounce its name.
2d. They aver that definitions are principles, and that we cannot dispute about definitions. These two assertions are contraries, and yet both of them false.
In the first place they are contradictory, for if definitions are principles, we can and we ought frequently to question their truth, as we ought never to recognise any principle as true without a previous examination, and if we cannot contest definitions, they cannot be principles, since every principle should be proved before it is admitted.
Again, these two assertions are both false. Definitions are not principles: for facts are the only true principles; and definitions are not facts, but simple explanations founded on facts, as all our other propositions whatsoever. Now we may contest a definition, as every other proposition; for when I explain the idea that I have of a being, I do not pretend to say merely that I have this idea; I pretend also to affirm that this idea agrees with that being, and that we may so conceive it without error; now this is what may be false, and what may be contested. So also when I explain the idea which I have of the sense of a word, I do not solely pretend that I have this idea, I pretend further that it does not affect the real relations of this word with an infinity of others, that we may employ it in this sense without inconvenience and without inconsequence; now this is what again may be contested with reason. In fine, if I should pretend by a definition only to explain the complex and compound idea that I have actually in my head, yet it should always be allowed to show me that this idea is badly formed, that it is composed of judgments inconsequent the one to the other, and that it includes contradictory elements. Then definitions never are principles, and yet they always are contestible.
3dly. The logicians have believed that the definition is good, and that the idea defined is perfectly explained when they have determined it, per genus proximum et differentiam specificam, as they say; that is to say, when they have expressed that one of its elements which constitutes it of such a genus, and the one which in this genus distinguishes it from the ideas of the neighbouring species. Now this is still false, and is only founded on the fantastical doctrine, in virtue of which they believed they v were able to distribute all our ideas into different arbitrary classes called categories.
That is false, first, because these arbitrary classifications never represent nature. Our ideas are connected the one to the other by a thousand different relations. Seen under one aspect they are of one genus, and under another they are of another genus; subsequently each of them depends on an innumerable multitude of proximate ideas, by an infinity of relations, of natures so different that we cannot compare them together, to decide which is the least remote. Thus we can never, or almost never find really the proximate genus or specific difference which deserves exclusively to characterise an idea.
Moreover, if we should have found in this idea the elements which in fact determine the genus and species in which it is reasonably permitted to class it, the idea would still be far from sufficiently explained, to be well known.
These two elements might even be absolutely foreign to the decision of the question which may have given place to the definition. Assuredly when I say that gold is a metal, and the heaviest of metals except platina, I have correctly ranged gold in the genus of beings to which it belongs, and I have distinguished it by a characteristic difference from those nearest to it in that genus. Yet this does not help me to know whether the use of gold, as money, is useful to commerce, or pernicious to morality, nor even whether it is the most ductile of metals. The two first questions depend on ideas too foreign to those which fix gold in a certain place amongst metals; and though the latter may be less distant, yet we do not know the direct and necessary relation between weight and ductility.
Logicians have been mistaken respecting the nature, the effects and properties of definitions. They are incapable of answering the end which they propose to attain by their means, that of presenting the idea of which we are to judge in such a manner that we cannot avoid forming a just judgment. The only mean of attaining this is to make the best description possible of the idea, and with the precautions which we have indicated.
It is necessary to observe that all that we have advised in the 8th, 9th and 10th aphorisms, and also what we shall advise hereafter to be done, to know well the idea, the subject of the judgment in question is equally applicable to the idea which is the attribute of the same judgment, a knowledge of which is equally essential, and can only be acquired by the same mean.
The means indicated above of knowing well the idea of which we are to judge, are the only really efficacious ones in bringing us to the formation of just judgments; but they may very possibly be insufficient to give us a certitude of having succeeded. We must therefore add subsidiary means.
The best and most useful of our secondary means is to see, on the one hand, if the judgment we are to form is not in opposition to anterior judgments, of the certitude of which we are assured; and on the other if it does not necessarily lead to consequences manifestly false.
The first point is that which has so strongly accredited the usage of general propositions; for, as we can confront them with a number of particular propositions, we have frequently had recourse thereto, and we have habituated ourselves to remount no further, and to believe that they are the primitive source of truth. The second is the motive of all those reasonings which consist in a reduction to what is absurd.