CHAPTER V.. Logic of the Stoics.

LOGIC OF THE STOICS.

Under the head of Logic, in the Stoic use of the term after the time of Chrysippus, a number of intellectual enquiries are included which would not now be considered to belong to philosophy at all. One common element, however, characterised them all—they all referred to the formal conditions of thought and expression. Logic was primarily divided into two parts, sharply marked off from each other, roughly described as the art of speaking continuously and the art of conversing. The former is known as Rhetoric, the latter as Dialectic. To these two was added, as a third part, the doctrine of a standard of truth, or the theory of knowledge; and, according to some authorities, a fourth part, consisting of enquiries into the formation of conceptions. By others, these enquiries were regarded as the third main division, the theory of knowledge being included under dialectic. By rhetoric, however, little else was meant than a collection of artificial rules, of no philosophical value; and dialectic was in great measure occupied with enquiries referring to precision of expression. Dialectic is defined to be the science or art of speaking well; and since speaking well consists in saying what is becoming and true, dialectic is used to express the knowledge of what is true or false, or what is neither one nor the other, correctness of expression being considered inseparable [(2) Words and thoughts.] from correctness of thought. Words and thoughts are, according to this view, the very same things regarded under different aspects. The same idea (λόγος), which is a thought as long as it resides within the breast, is a word as soon as it comes forth. Accordingly, dialectic consists of two main divisions, treating respectively of utterance and the thing uttered, thoughts and words. Both divisions, again, have several subdivisions, which are only imperfectly known to us. Under the science of utterance, which was generally placed before the science of things uttered, are included, not only instruction as to sounds and speech, but also the theories of poetry and music, these arts being ranked under the head of the voice and of sound on purely external considerations. What is known of the teaching of the Stoics on these subjects, consisting, as it does, of a mass of definitions, differences, and divisions, has so little philosophical value, that it need not detain attention longer. Two parts only of the Stoic logic possess any real interest—the theory of knowledge, and that part of dialectic which treats of ideas, and which in the main agrees with our formal logic.

The Stoic theory of knowledge turns about the enquiry for a criterion or standard by which what is true in notions may be distinguished from what is false. Since every kind of knowledge, no matter what be its object, must be tested by this standard, it follows that the standard cannot be sought in the subject-matter of notions, but, on the contrary, in their form. The enquiry after a standard becomes therefore identical with another—the enquiry as to what kind of notions supply a knowledge that may be depended upon, or what activity of the power of forming conceptions carries with it a pledge of its own truth. It is impossible to answer these questions without investigating the origin, the various kinds, and the value and importance of notions. Hence the problem proposed to the Stoics is reduced to seeking by an analysis of notions to obtain a universally valid standard by which their truth may be tested.

Whether this enquiry was pursued by the older Stoics in all its comprehensiveness is a point on which we have no information. Boëthus, whose views on this subject were attacked by Chrysippus, had assumed the existence of several standards, such as Reason, Perception, Desire, Knowledge. Others, in the vaguest manner, had spoken of Right Reason (ὀρθὸς λόγος) as being the standard of truth. Hence it may be inferred that before the time of Chrysippus the Stoics had no distinctly developed theory of knowledge. Nevertheless there are expressions of Zeno and Cleanthes still extant which prove that the essential parts of the later theory were already held by these philosophers, although it is no doubt true that it first received that scientific form in which alone it is known to us at the hands of Chrysippus.

The character of this theory of knowledge appears mainly in three particulars:—(1) In the importance attached by the Stoics to the impressions of the senses. This feature they inherited from the Cynics and shared with the Epicureans. (2) In the exaltation of expression into a conception—a trait distinguishing this from either of the two other contemporary Schools. (3) In the practical turn given to the question of a criterion or standard of truth. We proceed to the expansion of this theory in detail.

The origin of all perceptions (φαντασίαι) may be referred to the action of some object (φανταστὸν) on the soul, the soul at birth resembling a blank page, and only receiving definite features by experience from without. By the elder Stoics, this action of objects on the soul was regarded as grossly material, Zeno defining a perception to be an impression (τύπωσις) made on the soul, and Cleanthes took this definition so literally as to compare the impression on the soul to the impression made by a seal on wax. Being himself a very exact pupil of Zeno, Cleanthes probably rendered the views of Zeno correctly in this comparison. The difficulties of this view were recognised by Chrysippus, who accordingly defined a perception to be the change (ἑτεροίωσις) produced in the soul by an object, or, more accurately, the change produced thereby in the ruling part of the soul; and whereas his predecessors had only considered sensible things to be objects, he included among objects conditions and activities of the mind. The mode, however, in which the change was produced in the soul did not further engage his attention.

It follows, as a necessary corollary from this view, that the Stoics regarded sensation as the only source of all perceptions: the soul is a blank leaf, sensation is the hand which fills it with writing. But this is not all. Perceptions give rise to memory, repeated acts of memory to experience, and conclusions based on experience suggest conceptions which go beyond the sphere of direct sensation. These conclusions rest either upon the comparison, or upon the combination of perceptions, or else upon analogy; some add, upon transposition and contrast. The formation of conceptions by means of these agencies sometimes takes place methodically and artificially, at other times naturally and spontaneously. [(α) Κοιναὶ ἔννοιαι formed naturally.] In the latter way are formed the primary conceptions, προλήψεις or κοιναὶ ἔννοιαι, which were regarded by the Stoics as the natural types of truth and virtue, and as the distinctive possession of rational beings. To judge by many expressions, it might seem that by primary conceptions, or κοιναὶ ἔννοιαι, innate ideas were meant; but this view would be opposed to the whole character and connection of the system. In reality, these primary conceptions, or κοιναὶ ἔννοιαι, are only those conceptions which, by reason of the nature of thought, can be equally deduced by all men from experience; even the highest ideas, those of good and evil, having no other origin. The artificial formation of conceptions gives rise to knowledge, which is defined by the Stoics to be a fixed and immovable conception, or system of such conceptions. Persistently maintaining, [(β) Knowledge formed artificially.] on the one hand, that knowledge is a system of artificial conceptions, impossible without a logical process, they must, on the other hand, have felt it imperative from this platform that knowledge should agree in its results with primary conceptions, agreement with nature being in every department their watchword. For them it was as natural to derive support for their system from a supposed agreement with nature, as it was easy for their opponents to show that this agreement with nature was imaginary, and that many of their assertions were wholly opposed to general opinions.

Perceptions, and the conclusions based upon them, being thus, according to the Stoics, the two sources of all notions, the further question arises, How are these two sources related to each other? It might have been expected that only perceptions would be stated to be originally and absolutely true, since all general conceptions are based on them. Nevertheless, the Stoics are far from saying so. Absolute certainty of conviction they allow only to knowledge, and therefore declare that the truth of the perceptions of the senses depends on their relation to thought. Truth and error do not belong to disconnected notions, but to notions combined in the form of a judgment, and a judgment is produced by an effort of thought. Hence sensations, taken alone, are the source of no knowledge, knowledge first arising when the activity of the understanding is allied to sensation. Or, starting from the relation of thought to its object, since like can only be known by like according to the well-known adage, the rational element in the universe can only be known by the rational element in man. But again, the understanding has no other material to work upon but that supplied by sensation, and general conceptions are only obtained from sensation by conclusions. The mind, therefore, has the capacity of formally working up the material supplied by the senses, but to this material it is limited. Still, it can progress from perceptions to notions not immediately given in sensation, such as the conceptions of what is good and of God. And since, according to the Stoic teaching, material objects only possess reality, the same vague inconsistency may be observed in their teaching as has been noticed in Aristotle —reality attaching to individuals, truth to general notions. This inconsistency, however, is more marked in their case than in that of Aristotle, because the Stoics so far adhere to the Cynic nominalism as to assert that no reality attaches to thought. Such an assertion makes it all the more difficult to understand how greater truth can be attributed to thought, unreal as it is said to be, than to sensations of real and material objects. Do we then ask in what the peculiar character of thought consists, the Stoics, following Aristotle, reply that in thought the idea of universality is added to that which presents itself in sensation as a particular. More importance was attached by them to another point—the greater certainty which belongs to thought than to sensation. All the definitions given above point to the immovable strength of conviction as the distinctive feature of knowledge; and of like import is the language attributed to Zeno, comparing simple sensation with an extended finger, assent, as being the first activity of the power of judgment, with a closed hand, conception with the fist, and knowledge with one fist firmly grasped by the other. According to this view, the whole difference between the four processes is one of degree, and depends on the greater or less strength of conviction, on the mental exertion and tension. It is not an absolute difference in kind, but a relative difference, a gradual shading off of one into the other.

From these considerations it follows that in the last resort only a relative distinction is left whereby the truth of notions may be tested. Even the general argument for the possibility of knowledge starts with the Stoics by practically taking something for granted. Without failing to urge intellectual objections—and often most pertinent ones —against Scepticism, as was indeed natural, particularly since the time of Chrysippus, the Stoics nevertheless specially took up their stand on one point, which was this, that, unless the knowledge of truth were possible, it would be impossible to act on fixed principles and convictions. Thus, as a last bulwark against doubt, practical needs are appealed to.

The same result is obtained from a special enquiry into the nature of the standard of truth. If the question is asked, How are true perceptions distinguished from false ones? the immediate reply given by the Stoics is, that a true perception is one which represents a real object as it really is. You are no further with this answer, and the question has again to be asked, How may it be known that a perception faithfully represents a reality? The Stoics can only reply by pointing to a relative, but not to an absolute, test—the degree of strength with which certain perceptions force themselves on our notice. By itself a perception does not necessarily carry conviction or assent (συγκατάθεσις); for there can be no assent until the faculty of judgment is directed towards the perception, either for the purpose of allowing or of rejecting it, truth and error residing in judgment. Assent therefore, generally speaking, rests with us, as does also the power of decision; and a wise man differs from a fool quite as much by conviction as by action. Some of our perceptions are, however, of such a kind that they at once oblige us to bestow on them assent, compelling us not only to regard them as probable, but also as true and conformable to the actual nature of things. Such perceptions produce in us that strength of conviction which the Stoics call a conception; they are therefore termed conceptional perceptions. Whenever a perception forces itself upon us in this irresistible form, we are no longer dealing with a fiction of the imagination, but with something real; but whenever the strength of conviction is wanting, we cannot be sure of the truth of our perception. Or, expressing the same idea in the language of Stoicism, conceptional or irresistible perceptions, φαντασίαι καταληπτικαὶ, are the standard of truth. The test of irresistibility [(γ) Primary conceptions a standard as well as irresistible perceptions.] (κατάληψις) was, in the first place, understood to apply to sensations from without, such sensations, according to the Stoic view, alone supplying the material for knowledge. An equal degree of certainty was, however, attached to terms deduced from originally true data, either by the universal and natural exercise of thought, or by scientific processes of proof. Now, since among these derivative terms some—the primary conceptions (κοιναὶ ἔννοιαι), for instance—serve as the basis for deriving others, it may in a certain sense be asserted that sensation and primary conceptions are both standards of truth. In strict accuracy, neither sensation nor primary conceptions (πρόληψεις) can be called standards. The real standard, whereby the truth of a perception is ascertained, consists in the power, inherent in certain perceptions, of carrying conviction—τὸ καταληπτικὸν—a power which belongs, in the first place, to sensations, whether of objects without or within, and, in the next place, to primary conceptions formed from them in a natural way—κοιναὶ ἔννοιαι or προλήψεις. On the other hand, conceptions and terms formed artificially can only have their truth established by being subjected to a scientific process of proof. How, after these statements, the Stoics could attribute a greater strength of conviction to artificial than to primary conceptions; how they could raise doubts as to the trustworthiness of simple sensations, is one of the paradoxes of the Stoic system, which prove the existence, as in so many other systems, of a double current of thought. There is, on the one hand, a seeking for what is innate and original, a going back to nature, an aversion to everything artificial and of human device, inherited by Stoicism from its ancestral Cynicism. On the other hand, there is a desire to supplement the Cynic appeal to nature by a higher culture, and to assign scientific reasons for truths which the Cynics laid down as self-evident.

The latter tendency will alone explain the care and precision which the Stoics devoted to studying the forms and rules which govern intellectual processes. Attention to this branch of study may be noticed in Zeno and his immediate successors at the first separation of Stoicism from Cynicism. Aristo is the only Stoic who is opposed to it, his whole habit of mind being purely that of a Cynic. In Chrysippus it attained its greatest development, and by Chrysippus the formal logic of the Stoics reached scientific completeness. In later times, when Stoicism reverted more nearly to its original Cynic type, and appealed directly to the immediate suggestions of the mind, it lost its interest in logic, as may be observed in Musonius, Epictetus, and others. For the present, however, let it suffice to consider the logic of Chrysippus, as far as that is known to us.

The term formal logic is here used to express those investigations which the Stoics included under the doctrine of utterance. The common object of those enquiries is that which is thought, or, as the Stoics called it, that which is uttered (λεκτόν), understanding thereby the substance of thought—thought regarded by itself as a distinct something, differing alike from the external object to which it refers, from the sound by which it is expressed, and from the power of mind which produces it. For this reason, they maintain that only utterance is not material; things are always material; even the process of thought consists in a material change within the soul, and an uttered word, in a certain movement of the atmosphere. A question is here suggested in passing, which should not be lost sight of, viz. How far was it correct for the Stoics to speak of thoughts as existing, seeing they are not material, since, according to their teaching, reality only belongs to material things?

Utterance may be either perfect or imperfect. It is perfect when it contains a proposition; imperfect when the proposition is incomplete. The portion of logic, therefore, which treats of utterance falls into two parts, devoted respectively to the consideration of complete and incomplete expression.

In the section devoted to incomplete expression, much is found which we should include under grammar rather than under logic. Thus all incomplete expressions are divided into two groups—one group includes proper names and adjectives, the other includes verbs. These two groups are used respectively to express what is essential and what is accidental, and are again divided into a number of subdivisions and varieties. To this part of logic investigations into the formation and division of conceptions, and the doctrine of the categories, properly belong; but it cannot be said with certainty what place they occupy in the logic of the Stoics.

Certain it is that these researches introduced little new matter. All that is known of the Stoic views in reference to the formation, the mutual relation and the analysis of conceptions, differs only from the corresponding parts in the teaching of Aristotle by the change of a few expressions, and a slightly altered order of treatment.

Of greater importance is the Stoic doctrine of the categories. In this branch of logic, the Stoics again follow Aristotle, but not without deviating from him in three points. Aristotle referred his categories to no higher conception, but looked upon them severally as the highest class-conceptions; the Stoics referred them all to one higher conception. Aristotle enumerated ten categories; the Stoics thought that they could do with four, which four only partially coincide with those of Aristotle. Aristotle placed the categories side by side, as co-ordinate, so that no object could come under a second category in the same respect in which it came under the first one; the Stoics placed them one under the other, as subordinate, so that every preceding category is more accurately determined by the next succeeding one.

The highest conception of all was apparently by the older Stoics declared to be the conception of Being. Since, however, speaking strictly, only what is material can be said to have any being, and many of our notions refer to incorporeal and therefore unreal objects, the conception of Something was in later times put in the place of the conception of Being. This indefinite Something comprehends alike what is material and what is not material—in other words, what has being and what has not being; and the Stoics appear to have made this contrast the basis of a real division of things. When it becomes a question, however, of formal elementary conceptions or categories, other points are emphasised which have no connection with the division into things material and things not material. Of this kind are the four highest conceptions, —all subordinate to the conception of Something, viz. subject-matter or substance (τὸ ὑποκείμενον) property or form (τὸ ποιὸν), variety (τὸ πὼς ἔχον), and variety of relation (τὸ πρός τί πως ἔχον).

The first of these categories denotes the subject-matter of things in themselves (τὸ ὑποκείμενον), the material of which they are made, irrespective of any and every quality, the something which underlies all definite being, and which alone has a substantial value. Following Aristotle, the Stoics distinguish, in this category of matter, between matter in general, or universal matter, and the particular matter or material out of which individual things are made. The former alone is incapable of being increased or diminished. Far otherwise is the material of which particular things are made. This can be increased and diminished, and, indeed, is ever undergoing change; so much so, that the only feature which continues the same during the whole term of its existence and constitutes its identity, is its quality.

The second category, that of property or form, comprises all those essential attributes, by means of which a definite character is impressed on matter otherwise indeterminate. If the definite character be one which belongs to a group or class, it is called a common quality—κοινῶς ποιόν·—or, if it be something peculiar and distinctive, it is called a distinctive quality—ἰδίως ποιόν. Properties therefore combined with matter constitute the special materials out of which individual things are made; and quality in this combination (ποιόν), corresponds, as Trendelenburg has well shown, with the form (εἶδος) of Aristotle. It may, in fact, like that, be described as the active and efficient part of a thing. Aristotle’s form, however, expresses only the non-material side of a thing, whereas quality is regarded by the Stoics as something material—in fact, as an air-current. Hence the mode in which a quality is conceived to reside in matter is that of an intermingling of elements. The same theory of intermingling applies of course to the union of several properties in one and the same matter, and likewise to the combination of several attributes to produce a single conception of quality. In all cases the relation is supposed to be materialistic, and is explained by the doctrine of the mutual interpenetration of material things. This explanation, indeed, could not apply to every kind of attributes. Unable to dispense entirely with things not material, the Stoics were obliged to admit the existence of attributes belonging to immaterial things, these attributes being, of course, themselves not material. What idea they formed to themselves of these incorporeal attributes, when reality was considered to belong only to things corporeal, it is, of course, impossible for us to say.

The two remaining categories include everything which may be excluded from the conception of a thing on the ground of being either non-essential or accidental. In as far as such things belong to an object taken by itself alone, they come under the category of variety (πὼς ἔχον); but when they belong to it, because of its relation to something else, they come under the category of variety of relation (πρός τί πως ἔχον). Variety includes all accidental qualities, which can be assigned to any object independently of its relation to any other object. Size, colour, place, time, action, passion, possession, motion, state, in short, all the Aristotelian categories, with the exception of substance, whenever they apply to an object independently of its relation to other objects, belong to the category of variety (πὼς ἔχον). On the other hand, those features and states which are purely relative—such as right and left, sonship and fatherhood, &c.—come under the category of variety of relation (πρός τί πως ἔχον); and from this category the simple notion of relation (πρὸς τὶ) must be distinguished. Simple relation (πρὸς τὶ) is not treated as a distinct category, since it includes not only accidental relations, but also those essential properties (ποιὰ) which presuppose a definite relation to something else—such as knowledge and perception.

The relation of these four categories to one another is such, that each preceding category is included in the one next following, and receives from it a more definite character. Substance never occurs in reality without property, but has always some definite quality to give it a character. On the other hand, property is never met with alone, but always in connection with some subject-matter. Variety presupposes some definite substance, and variety of relation supposes the existence of variety. It will hereafter be seen how closely these deductions, and, indeed, the whole doctrine of the categories, depend on the metaphysical peculiarities of the Stoic system.

Passing from incomplete to complete utterance, we come, in the first place, to sentences or propositions, all the various kinds of which, as they may be deduced from the different forms of syntax, are enumerated by the Stoics with the greatest precision. Detailed information is, however, only forthcoming in reference to the theory of judgment (ἀξίωμα), which certainly occupied the chief and most important place in their speculations. A judgment is a perfect utterance, which is either true or false. Judgments are divided into two classes: simple judgments, and composite judgments. By a simple judgment the Stoics understand a judgment which is purely categorical. Under the head of composite judgments are comprised hypothetical, corroborative, copulative, disjunctive, comparative, and causal [(α) Simple judgment.] judgments. In the case of simple judgments, a greater or less definiteness of expression is substituted in place of the ordinary difference in respect of quantity; and with regard to quality, they not only make a distinction between affirmative and negative judgments, but, following the various forms of language, they speak of judgments of general negation, judgments of particular negation, and judgments of double negation. Only affirmative and negative judgments have a contradictory relation to one another; all other judgments stand to each other in the relation of contraries. Of two propositions which are related as contradictories, according to the old rule, one must be true and the other false.

Among composite judgments the most important are the hypothetical and the disjunctive. As regards the latter, next to no information has reached us. A hypothetical judgment (συνημμένον) is a judgment consisting of two clauses, connected by the conjunction ‘if,’ and related to one another as cause and effect; the former being called the leading (ἡγούμενον), and the latter the concluding or inferential clause (λῆγον). In the correctness of the inference the truth of a hypothetical judgment consists. As to the conditions upon which the accuracy of an inference rests, different opinions were entertained within the Stoic School itself. In as far as the leading clause states something, from the existence of which an inference may be drawn for the statement in the concluding clause, it is also called an indication or suggestive sign.

The modality of judgments, which engaged the attention of Aristotle and his immediate pupils so much, was likewise treated by the Stoics at considerable length; but of this branch of enquiry so much only is known to us as concerns possible and necessary judgments, and it is the outcome chiefly of the contest between Chrysippus and the Megarian Diodorus. It is in itself of no great value. By the Stoics, nevertheless, great value was attached to it, in the hope of escaping thereby the difficulties which necessarily result from their views on freedom and necessity.

In their theory of illation, to which the Stoics attached special value, and on which they greatly prided themselves, chief attention was paid to hypothetical and disjunctive inferences. In regard to these forms of inference, the rules they laid down are well known: and from these forms they invariably take their examples, even when treating of inference [(α) Hypothetical inference the original form.] in general. According to Alexander, the hypothetical and disjunctive forms are held to be the only regular forms of inference; the categorical form is considered correct in point of fact, but defective in syllogistic form. In hypothetical inferences a distinction was also made between such as are connected and such as are disconnected. In connected inferences the Stoics look principally at the greater or less accuracy of expression, and partly at the difference between correctness of form and truth of matter. They also remark that true conclusions do not always extend the field of knowledge; and that those which do frequently depend on reasons conclusive for the individual, but not on proofs universally acknowledged. The main point, however, to be considered in dividing inferences is their [(β) The five simple forms of hypothetical inference.] logical form. There are, according to Chrysippus, who herein adopted the division of Theophrastus, five original forms of hypothetical inference, the accuracy of which is beyond dispute, and to which all other forms of inference may be referred and by which they may be tested. Yet even among these five, importance is attached to some in which the same sentence is repeated tautologically in the form of a conclusion, which proves how mechanical and barren must have been the formalism with which the Stoic logic abounds.

The combination of these five simple forms of inference gives rise to the composite forms of inference, all of which may be again resolved into their simple forms. Among composite forms of inference, those composed of similar parts are distinguished from those composed of dissimilar parts; in the treatment of the former, however, such a useless formality is displayed, that it is hard to say what meaning the Stoics attached to them. If two or more inferences, the conclusion of one of which is the first premiss of the other, are so combined that the judgment which constitutes the conclusion and premiss at once is omitted in each case, the result is a Sorites or Chain-inference. The rules prescribed by the Peripatetics for the Chain-inference are developed by the Stoics with a minuteness far transcending all the requirements of science. With these [(δ) Inference from a single premiss.] composite forms of inference Antipater contrasted other forms having only a single premiss, but it was an addition to the field of logic of very doubtful worth. On a few other points connected with the Stoic theory of illation, we have very imperfect information. The loss, however, is not to be regretted, seeing that in what we already possess there is conclusive evidence that the objections brought against the Stoic logic were really well deserved, because of the microscopic care expended by them on the most worthless logical forms.

Next to describing inferences which are valid, another subject engaged the close attention of the Stoics, and afforded opportunity for displaying their dialectical subtlety. This is the enumeration and refutation of false inferences, and in particular the exposing of the many fallacies which had become current since the age of the Sophists and Megarians. In this department, as might be expected, Chrysippus led the way. Not that Chrysippus was always able to overcome the difficulties that arose; witness his remarkable attitude towards the Chain-inference, from which he thought to escape by withholding judgment. The fallacies, however, to which the Stoics devoted their attention, and the way in which they met them, need not occupy our attention further.

In all these researches the Stoics were striving to find firm ground for a scientific process of proof. Great as was the value which they attached to such a process, they nevertheless admitted, as Aristotle had done before, that everything could not be proved. Here was their weak point. Instead, however, of strengthening this weak point by means of induction, and endeavouring to obtain a more complete theory of induction, they were content with conjectural data, sometimes self-evident, at other times depending for their truth on the truth of their inferences. Thus, their theory of method, like their theory of knowledge, ended by an ultimate appeal to what is directly certain.

No very high estimate can therefore be formed of the formal logic of the Stoics. Incomplete as our knowledge of that logic may be, still what is known is enough to determine the judgment absolutely. We see indeed that the greatest care was expended by the Stoics since the time of Chrysippus in tracing the forms of intellectual procedure into their minutest ramifications, and referring them to fixed types. At the same time, we see that the real business of logic was lost sight of in the process, the business of portraying the operations of thought, and giving its laws, whilst the most useless trifling with forms was recklessly indulged in. The Stoics can have made no discoveries of importance even as to logical forms, or they would not have been passed over by writers ever on the alert to note the slightest deviation from the Aristotelian logic. Hence the whole contribution of the Stoics to the field of logic consists in their having clothed the logic of the Peripatetics with a new terminology, and having developed certain parts of it with painful minuteness, whilst they wholly neglected other parts, as was the fate of the part treating of inference. Assuredly it was no improvement for Chrysippus to regard the hypothetical rather than the categorical as the original form of inference. Making every allowance for the extension of the field of logic, in scientific precision it lost more than it gained by the labours of Chrysippus. The history of philosophy cannot pass over in silence this branch of the Stoic system, so carefully cultivated by the Stoics themselves, and so characteristic of their intellectual attitude. Yet, when all has been said, the Stoic logic is only an outpost of their system, and the care which was lavished on it since the time of Chrysippus indicates the decline of intellectual originality.