THE STOICS

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The early Stoics, especially Chrysippus, were prolific writes, but what they wrote has been almost completely lost. So we depend on what others wrote about them. Cicero is one of our most important sources.

⊕ Cicero was primarily a Roman statesman. He lived from 106-43 BCE. Toward the end of his life in 46-44 BCE, because he was sidelined from politics, he wrote a series of works to present philosophy (which had been written in Greek) in his native Latin. The point was not to make philosophy available to the Roman elite. They were bilingual. It was to show that philosophy could be conducted in Latin. In his On Ends I.1.3, Cicero describes this project as a "labor of love." In part, it required Cicero to create a new philosophical vocabulary in Latin.

Cicero's philosophical works:

The Academica discusses the Stoics and the Academics on the possibility of knowledge. It is reconstructed from fragments of two works. The first (Lucullus or Academica Priora) consists in the now lost Catulus and the extant Lucullus. The second (Varro or Academica Posteriora) consists in the Academic Books, of which only part of the first book is extant.

Academica I (Varro) is what remains of the Academic Books.

Academica II (Lucullus) is the Lucullus.

Academica I consists mostly in Varro's speech on the history of philosophy from the point of view of Antiochus (I.15–42) and Cicero's alternative from the point of view of the Academics (I.43-46).

Academica II consists mostly in Lucullus's speech on the Stoics (II.10–62) and Cicero's defense of the Academics in reply (II.64–147).

On Divination (in two books) contains arguments for divination and refutations of these arguments.

On Ends (in five books) is a critical discussion of ethical views. There are separate dialogues devoted to each of the three views. The first (in books one and two) sets out Epicurean ethics and refutes it from the point the Stoics. The second dialogue (in books three and four) sets out Stoic ethics and refutes it from the point of view the Academics.

On the Nature of the Gods sets out (in three books) the theological views of the Epicureans, Stoics, and Academics.

Stoic Paradoxes (in six essays) discusses some of the more striking Stoic doctrines. The essays are intended as amusing popularizations, not serious works in philosophy.

Topica.

Tusculan Disputations (in five books) discusses the fear of death, the endurance of pain, the alleviation of distress, the remaining disorders of the soul, and the sufficiency of virtue for a happy life. (The discussions in the Tusculan Disputations take place in Cicero's villa in Tusculum (a now ruined Roman city about 14 miles south of Rome).)

Cicero (106-43 BCE)

The most important early Stoics (Zeno, Cleanthes, and Chrysippus) were dead when Cicero writes.

Zeno of Citium founded the school in about 300 BCE. Cleanthes and Chrysippus were the second and third leaders of the school. Chrysippus died in about 206 BCE. The school itself continued.

• Academica I.40
(Part of Varro's speech I.15-42) ⊕




Cicero's Latin translations of Greek philosophical terms can be hard to keep straight. Here is a partial list with English translations.

adsensio, "assent"
approbatio, "approval"
συγκατάθεσις, noun, "assent"

appetitio, "a grasping at, reaching after"
ὁρμή, noun, "impulse"

comprehensibilis, "graspable"
καταληπτός, adjective, "capable of being seized or grasped"

comprehensio, "grasp"
perceptio, "taking in, receiving"
κατάληψις, noun, "seizing"

"...cognition (cognitio) or perception (perceptio) or, to translate literally, grasp (comprehensio), they call κατάληψις..." (Academica II.17).

"The cognitions (cognitiones) of things (which we may term comprehensions (comprehensiones) or perceptions (perceptiones), or, if these words are distasteful or obscure, καταλήψεις..." (On Ends III.17).

impressio
visum
visio
φαντασία, noun, "impression"

visum comprehendible
καταληπτικὴ φαντασία, "cognitive impression"

inscientia, "ignorance"
ignorantia, "want of information, ignorance"
ἄγνοια, "want of perception, ignorance"

notio, "concept or notion"
ἔννοια, noun,
πρόληψις, noun,

"By concept (notio) I mean what the Greeks call now ἔννοια, now πρόληψις. This is an innate knowledge of anything, which has been previously grasped, and needs to be unfolded" (Topica VII.1.31).

opinio, "opinion"
δόξα, "belief"

probabilis, "likely, credible, probable"
πιθανός, adjective, "persuasive, plausible"

sapientia, "wisdom"
φρόνησις

scientia, "knowledge"
ἐπιστήμη, "knowledge"

virtus, "virtue"
ἀρετή, "virtue"


perspicuus,

The alterations [Zeno] made in the third part of philosophy [reasoning and argument, I.30] were more extensive. The first change here was his innovative set of claims about sense-perception itself. He considered sense-perceptions to be compounds of a kind of externally induced impact—he called this a φαντασία, but we can call it an impression (and let’s hold on to this term, since we’re going to need it rather often in the rest of our conversation). But, as I was saying, he conjoined these—the impressions received by the senses, so to speak—with the assent of our minds, which he took to be in us and voluntary.

• Academica II.24
(Lucullus’ Speech II.11-62)

⊕ There must be something for wisdom to follow when it begins to act, and this must be suited to our nature; for otherwise appetition (our equivalent for ὁρμή, by which we are impelled towards the object of our impression, cannot be set in motion; but we must have an impression of the thing that sets impulse in motion, and we must accept the impression, and this cannot take place if the object is indistinguishable from something false.

• Academica II.37
(Lucullus’ Speech II.11-62)

I will make a couple of points about approval or assent (which the Greeks call συγκατάθεσις). This is a big topic, of course, but we did the groundwork a bit earlier. First, when I was explaining the power of the senses, it also became clear that many things are grasped by them, which can’t happen without assent.

• Academica II.38
(Lucullus’ Speech II.11-62)

For just as the balance of a scale must sink down when weights are placed on it, so the mind must yield to clear impressions; just as an animal can’t fail to have an impulse towards something that appears suited to its nature (what the Greeks call οἰκεῖον), it can’t fail to approve a clear thing it is presented with.

Notes on the Text

Zeno founded the Stoic school in about 300 BCE.

The Stoics thought that we have impressions. When I look at something, for example, the thing might impress itself on me in such a way that I get the impression that it is red.

"An impression is an imprint on the soul: the name having been appropriately borrowed from the imprint made by the seal upon the wax" (Diogenes Laertius, Lives of the Philosophers VII.1.45).

Diogenes Laertius lived in the 3rd century CE. Life of Zeno = Lives of the Philosophers VII.1

Adults can assent to their impressions. Children and animals cannot assent because they do not have reason, but they do not need to assent. Nature in its providence has arranged things so that when children and animals get certain impressions, they get the appropriate impulses to maintain themselves.

Impressions in adults have propositions as their content.

"Another division of impressions is into rational and irrational, the former being those of rational creatures, the latter the irrational. Rational impressions are thoughts (νοήσεις), while those which are irrational have no name" (Diogenes Laertius, Lives of the Philosophers VII.1.51).

Assent to the impression results in a propositional attitude to the proposition.

In adults, assent is necessary for impulse and hence for action.

• Academica I.41
(Part of Varro's speech I.15-42)

  Zeno didn’t put his trust in all impressions but only in those that revealed their objects in a special way. Since this kind of impression could be discerned just by itself, he called it cognitive.—Can you bear this?
  Of course. How else could you translate καταληπτόν.
  But once it had been received and approved, he called it a cognition or grasp, like something grasped by one’s hand. (In fact, that was his source for this term, since no one had used this word for that kind of thing before. Zeno used a lot of novel terms, but what he was saying was new, too.) He called an impression that had been apprehended by one of the senses a perception itself. And if it had been apprehended in such a way that it couldn’t be dislodged by reason, he called it knowledge, if not, ignorance. The latter was also the source of opinion, which was a weak condition covering false as well as unknown impressions.

• Academica II.145
(Cicero’s Speech 64-147)

Zeno used to demonstrate this with gestures. When he had put his hand out flat in front him with his fingers straight, he would say an impression is like this. Next, after contracting his fingers a bit, he would say assent is like this. Then, when he had bunched his hand up to make a fist, he would say that that was a cognition. (This image also suggested the name he gave to it, κατάληψις, which hadn’t been used before.) Finally, when he had put his left hand on top, squeezing his fist tight with some force, he would say that knowledge was like that: a state none but the wise enjoyed—though as for who is or ever was wise, even they aren’t in a rush to say.

Notes on the Text

Some impressions are cognitive. These impressions are "clear" and "distinct."

Cognition consists in assent to a cognitive impression.

Knowledge consists in assent to a cognitive impression that no rational means can convince one to withdraw.

An assent is knowledge or opinion but not both.

Only the wise have knowledge, but no one is wise. In this, the Stoics follow Socrates. His interlocutors could not answer his questions about their beliefs without contradicting themselves.

⊕ "According to [the Stoics], ... of men the greatest number are bad, or rather there are one or two whom they speak of as having become good men as in a fable, a sort of incredible creature as it were and contrary to nature and rarer than the Ethiopian phoenix; and the others are all wicked and are so to an equal extent, so that there is no difference between one and another, and all who are not wise are alike mad" (Alexander of Aprodisias, De fato XXVIII).

(For the Ethiopian phoenix, see Herodotus, Histories II.73.1 and Pliny the Elder, The Natural History X.2.) "It happens more often that a mule brings forth a colt than that nature produces a wise man" (On Divination II.28.61). "The man in whom there is perfect wisdom—we have never seen a living example, but his character, if only one day he can be found, is described in the words of philosophers..." (Tusculan Disputations II.22.51).

"Of impressions, some are cognitive and some are not. The former, which they say is the criterion of reality, is defined as that which proceeds from a real object, agrees with that object itself, and has been imprinted seal-fashion and stamped upon the mind: the latter, that which does not proceed from any real object, or, if it does, fails to agree with the reality itself, not being clear or distinct" (Diogenes Laertius, Lives of the Philosophers VII.1.45).

• Academica I.39

⊕ "[W]e prefer to apply the term disorders (perturbationes) rather than diseases to what the Greeks call πάθη" (Tusculan Disputations IV.5.10).

"This is Zeno’s definition of disorder, which he terms πάθος, that it is an agitation of the soul alien from right reason and contrary to nature" (Tusculan Disputations IV.6.11).

"They think all disorders are due to judgment and opinion" (Tusculan Disputations IV.7.14).

"Chrysippus says that passion is an irrational and unnatural movement of the soul and an excessive impulse" (Galen, On the Doctrines of Hippocrates and Plato IV.2.8-9).

Galen of Pergamum (130-210 CE) is a Greek physician and philosopher. He wrote the first six (of the nine) books of On the Doctrines of Hippocrates and Plato in 162 to 166 CE. His aim was to show that Hippocrates and Plato agreed and were correct about the faculties of animals. The work is largely polemical. In books III-V, he attacks Chrysippus' understanding of the soul and conception of the passions.

"Passion is defined by Zeno as an irrational and unnatural movement in the soul, or again as impulse in excess (ὁρμὴ πλεονάζουσα)" (Diogenes Laertius, Lives of the Philosophers VII. 1.110).

"They hold the passions (πάθη) to be judgements, as is stated by Chrysippus in his treatise On the Passions" (Diogenes Laertius, Lives of the Philosophers VII. 1.111).

"[T]hey say that the wise man is free from passion (ἀπαθῆ)" (Diogenes Laertius, Lives of the Philosophers VII. 1.117). Whereas the ancients [Plato and Aristotle] claimed the disorders are natural and have nothing to do with reason, and whereas they located desire in one part of the soul, and reason in another, Zeno would not agree with that. He thought that they were equally voluntary and arose from a judgment which was a matter of opinion.

• Academica I.42
(Part of Varro's speech I.15-42)

But to the cognition I mentioned Zeno assigned a position in between knowledge and ignorance, counting it as neither good nor bad, though he said it alone warranted our trust. Owing to it he also rated the senses as trustworthy, since, as I said before, he thought that an cognition caused by the senses was true and reliable—not because it grasped all the features of its object, but on the ground that it omitted nothing detectable by it. Another reason was that nature had given cognition as a standard and starting point for knowledge of the world: it was the source from which our conceptions of things were later stamped on our minds, which in turn give rise not just to the starting points but to certain broader paths for discovering reason. But error, rashness, ignorance, opinion, supposition, and, in a word, everything foreign to stable and consistent assent, he excluded from virtue and wisdom. These were pretty much all the changes marking Zeno’s disagreement with his predecessors.

• Academica II.30
(Lucullus’ Speech II.11-62)

[T]he amount of craftsmanship that nature has employed in the construction first of every animal, then most of all in man,—the power possessed by the senses, the way in which we are first struck by the sense impressions, next follows appetition imparted by their impact, and then we direct the senses to perceive the objects. For the mind itself, which is the source of the sensations and even is itself sensation, has a natural force which it directs to the things by which it is moved. Accordingly some sense impressentations it seizes on so as to make use of them at once, others it as it were stores away, these being the source of memory, while all the rest it unites into systems by their mutual resemblances, and from these are formed the concepts of objects ⊕ "[We get] a fully completed grasp of things, for instance, 'If it is a human being, it is a rational mortal animal.' From this set are imprinted upon us our notions of things, without which all understanding and all investigation and discussion are impossible" (Academica II.21).

"And nature, the Stoics say, made no difference originally between plants and animals, for she regulates the life of plants too, in their case without impulse and sensation, just as also certain processes go on of a vegetative kind in us. But when in the case of animals impulse has been superadded, whereby they are enabled to go in quest of their proper aliment, for them, say the Stoics, Nature's rule is to follow the direction of impulse. But when reason by way of a more perfect leadership has been bestowed on the beings we call rational, for them life according to reason rightly becomes the natural life. For reason artfully directs impulse. This is why Zeno was the first (in his treatise On the Nature of Man) to designate as the end 'life in agreement with nature' (or living agreeably to nature), which is the same as a virtuous life, virtue being the goal towards which nature guides us. ... And this is why the end may be defined as life in accordance with nature, or, in other words, in accordance with our own human nature as well as that of the universe, a life in which we refrain from every action forbidden by the law common to all things, that is to say, the right reason which pervades all things, and is identical with this Zeus, lord and ruler of all that is. And this very thing constitutes the virtue of the happy man and the smooth current of life, when all actions promote the harmony of the spirit dwelling in the individual man with the will of him who orders the universe" (Diogenes Laertius, Lives of the Philosophers VII.1.86-88). which the Greeks term sometimes ἐννοίας and sometimes προλήψεις. When thereto there has been added reason and proof and an innumerable multitude of facts, then comes the clear perception of all these things, and also this same reason having been by these stages made complete finally attains to wisdom. Since therefore the mind of man is supremely well adapted for the knowledge of things and for consistency of life, it welcomes knowledge beyond all else, and your κατάληψιν, which as I said we will express by a literal translation as ‘grasp,’ is loved by the mind both for itself (for nothing is dearer to the mind than the light of truth) and also for the sake of its utility. Hence the mind employs the senses, and also creates the sciences as a second set of senses, and strengthens the structure of philosophy itself to the point where it may produce virtue, the sole source of the ordering of the whole of life.

Notes on the Text

Human beings develop reason as they mature. Their souls start out as nonrational. As humans mature, this nonrational soul is transformed and replaced by a rational soul. (It is important to distinguish the Stoic view from Aristotle's. He too thinks that humans develop reason as they mature. Unlike the Stoics, though, he thinks the nonrational part of the soul survives in the adult and coexists with the rational part of the soul.)

"When a man is born, the Stoics say, he has the commanding-part (ἡγεμονικὸν) of his soul like a sheet of paper ready for writing upon. On this he inscribes each of his conceptions. The first method of inscription is through the senses. For by perceiving something, e.g., white, they have a memory of it when it has departed. And when many memories of a similar kind have occurred, we then say we have experience (ἐμπειρίαν). For the plurality of similar impressions is experience. Some conceptions arise naturally in the aforesaid ways and undesignatedly, others through our own instruction and attention. The later are called 'conceptions (ἔννοιαι)' only, the former are called 'preconceptions (προλήψεων)' as well. Reason (λόγος), for which we are called rational (λογικοί), is said to be completed from our preconceptions during our first seven years" (Pseudo-Plutarch, Placita 4.11).

Pseudo-Plutarch (2nd century CE) Placita Philosophorum (Views of the Philosophers) (once wrongly attributed to Plutarch) records views of the philosophers on physics. Stobaeus (5th century CE) and Theodoret (5th century CE) preserve parts of this same work. Theodoret names (the otherwise unknown) Aëtius as the source.

"A notion is an impression to the intellect" (Diogenes Laertius, Lives of the Philosophers VII.1.61).

"The notions of justice and goodness come by nature" (Diogenes Laertius, Lives of the Philosophers VII.53).

• On the Nature of the Gods I.39

⊕ "God is one and the same with Mind, Fate, and Zeus (νοῦν καὶ εἱμαρμένην καὶ Δία); he is also called by many other names" (Diogenes Laertius, Lives of the Philosophers VII.135). Chrysippus..., musters an enormous mob of unknown gods.... He says that the divine power resides in reason, and the soul and mind of the universe; the the world itself a god, and also the all-pervading world-soul, and again the guiding principle of that soul, which operates in the intellect and reason, and the common and all-embracing nature of things; and also the power of fate, and the necessity that governs future events.

• On Divination 1.125

By fate, I mean what the Greeks call εἱμαρμένῃ--an ordering and sequence of causes, since it is the connection of cause to cause which out of itself produces anything. It is everlasting truth, flowing from all eternity. Consequently nothing has happened which was not going to be, and likewise nothing is going to be of which nature does not contain causes working to bring that very thing about. This makes it intelligible that fate should be, not the fate of superstition, but that of physics, an everlasting cause of things--why past things happened, why present things are now happening, and why future things will be.

Notes on the Text

• On Ends III.16

⊕ "An animal's first impulse, say the Stoics, is to self-preservation, because nature from the outset endears it to itself, as Chrysippus affirms in the first book of his work On Ends....[N]ature in constituting the animal made it near and dear to itself; for so it comes to repel all that is injurious and give free access to all that is serviceable or akin to it" (Diogenes Laertius, Lives of the Philosophers VII.1.85). It is the view of whose system I [Cato, who speaks for the Stoics] adopt, that immediately upon birth (for that is the proper point to start from) a living creature feels an attachment for itself, and an impulse to preserve itself and to feel affection for its own constitution and for those things which tend to preserve that constitution; while on the other hand it conceives an antipathy to destruction and to those things which appear to threaten destruction. In proof of this opinion they urge that infants desire things conducive to their health and reject things that are the opposite before they have ever felt pleasure or pain; this would not be the case, unless they felt an affection for their own constitution and were afraid of destruction

• On Ends III.20

⊕ ⊕ [T]he first appropriate act' (for so I render the Greek καθῆκον) is to preserve oneself in one's natural constitution; the next is to retain those things which are in accordance with nature and to repel those that are the contrary; then when this principle of choice and also of rejection has been discovered, there follows next in order choice conditioned by 'appropriate action'; then, such choice become a fixed habit; and finally, choice fully rationalized and in harmony with nature. It is at the right aim, this final stage that the good properly so called first emerges and comes to be understood in its true nature. For originally man comes to be attached to those things which are in accordance with nature. But as soon as he has gained this understanding, or rather this notion which they call ἔννοιαν, and he has come to see the order and, to put it this way, concord of the things to be done, he has come to value this concord so much more than all those things he had originally come to hold dear. And thus by insight and reasoning (cognitione et ratione) he has come to the conclusion that this highest good of men which is worthy of praise or admiration and desirable for its own sake lies precisely in this. It rests in what the Stoics call ὁμολογιαν, but which we may call agreement.

Notes on the Text

• Tusculan Disputations IV.6.12

⊕ "Also they [the Stoics] say that there are three emotional states which are good, namely, joy, caution, and wishing (χαράν, εὐλάβειαν, βούλησιν). Joy, the counterpart of pleasure, is rational elation; caution, the counterpart of fear, rational avoidance; for though the wise man will never feel fear, he will yet use caution. And they make wishing the counterpart of desire (or craving), inasmuch as it is rational impulse" (Diogenes Laertius, Lives of the Philosophers VII.1.116).

"Zeno says that even the wise man’s mind will keep its scar long after the wound has healed. He will experience, therefore, certain suggestions and shadows of passion, but from passion itself he will be free" (Seneca, On Anger I.16.7). (See also Plato, Gorgias 524e and Homer, Odyssey 11.40.)

"That only the wise man is free, and that every foolish man is a slave" (Stoic Paradoxes V).

"[T]hey say that the wise man will never form opinions, that is to say, he will never give assent to anything that is false. ... [And] they declare that he alone is free" (Diogenes Laertius, Lives of the Philosophers VII.1.121).


Stoic πάθη and εὐπάθειαι

For by a law of nature all men pursue apparent good and shun its opposite; for which reason, as soon as the semblance of any apparent good presents itself, nature of itself prompts them to secure it. Where this takes place in an equable and wise way the Stoics employ the term βούλησις for this sort of longing, we should employ the term wish. That, they think, is found in the wise man alone and they define it in this way: wish is a rational longing for anything. Where, however, wish is alien from reason and is too violently aroused, it is lust or unbridled desire, which is found in all fools. And also, where we are satisfied that we are in possession of some good, this comes about in two ways: for when the soul has this satisfaction rationally and in a tranquil and equable way, then the term joy is employed; when on the other hand the soul is in a transport of meaningless extravagance, then the satisfaction can be termed exuberant or excessive delight and this they define as irrational excitement of the soul. And since we naturally desire good in the same manner as we naturally turn away from evil, and such a turning away, when rational, would be called precaution, and is consequently found in the wise man only; but when dissociated from reason and associated with mean and abject pusillanimity, it would be named fear; therefore fear is precaution alien from reason. The wise man, however, is not subject to the influence of present evil; fools are subject to distress and feel its influence in the face of expected evil, and their souls are downcast and shrunken together in disobedience to reason. And consequently the first definition of distress is that it is a shrinking together of the soul in conflict with reason. Thus there are four disorders, three equable states, since there is no equable state in opposition to distress.

Notes on the Text

⊕ "It is a tenet of theirs that between virtue and vice there is nothing" (Diogenes Laertius, Lives of the Philosophers VII.1.127). The Stoics thought that adults are either fools or are wise.

Fools suffer from passions. The wise do not. They are ἀπαθεῖς.

This, though, does not mean that the wise are without emotion. They know "joy," "caution," and "wishing."

Consider "caution." In fools, what corresponds to this emotion is "fear."

The fool has false believes about what is good and what is bad. Suppose he believes that death is bad and that he gets and assents to the impression that he is in danger of dying. His assent issues in an "excessive impulse" (ὁρμὴ πλεονάζουσα) to eliminate this danger. This impulse is "excessive" because it is way out of proportion to the value of his death. He thinks death is bad, but in fact it is indifferent.

The wise do not have false beliefs about what is good and what is bad. He understands that nature in its providence arranges things so that in general living things find food when they are hungry, recover from illness when they are ill, and so on. He does not know whether nature has arranged things so that in his case he will avoid death, but given his understanding of the arrangement in nature generally, he knows it is reasonable for him to to try to avoid his death. So, like the fool, he tries to eliminate the danger, but his impulse is not excessive.

⊕ ⊕ • Academica II.36
(Lucullus’ Speech II.11-62)

⊕ What then is the persuasiveness that your school [the Academics] talk about? ... [W]hen they say that it can happen to the wise man that after he has taken every precaution and explored the position most carefully, something may yet arise that while appearing to resemble truth (veri simile) is really very remote from truth, they will be unable to trust themselves, even if they advance at all events a large part of the way, as they are in the habit of saying, towards the truth, or indeed come as near to it as possible. For to enable them to trust their judgement, it will be necessary for the characteristic mark of truth to be known to them, and if this be obscured and suppressed, what truth will they suppose that they attain to?

• Academica II.99.

Carneades holds that there are two classifications of impressions, which under one are divided into those that can be perceived and those that cannot, and under the other into those that are persuasive (probabilia) and those that are not persuasive.... [H]is view is that there is no impression of such a sort as to result in perception [no cognitive impression], but many that result in a judgement of persuasiveness. For it is contrary to nature for nothing to be persuasive, and entails that entire subversion of life"

Notes on the Text

• Carneades seems to have argued that assent to "persuasive" impressions is permitted. Lucullus because, as the Academics admit, a persuasive impression can be false.

Sextus Empiricus (2nd or 3rd century CE)

Sextus Empiricus was a physician and philosopher (in the empirical and Pyrrhonian tradition).

⊕ In a list of Empiricist physicians, Diogenes Laertius mentions "Sextus the Empiricist" (Lives of the Philosophers IX.116).

Sextus Empiricus says that he himself wrote a (now lost) set of discourses on Empiricism (Against the Grammarians III.61). Sextus Empiricus's surviving works include:

Outlines of Pyrrhonism
Against the Mathematicians (Adversus Mathematicos)

Against the Mathematicians (M) is in eleven books that have separate titles:

Against the Grammarians is M I
Against the Logicians I and II is M VII and M VIII.
Against the Physicists I and II is M IX and M X
Against the Ethicists is M XI.

• Against the Logicians I.151

⊕ "These men [the Stoics], then, assert that the criterion of truth is the cognitive impression" (Against the Logicians I.227).

"Knowledge itself they define either as secure cognition or as a habit or state which in reception of impressions cannot be shaken by argument. Without the study of dialectic, they say, the wise man cannot guard himself in argument so as never to fall; for it enables him to distinguish between truth and falsehood, and to discriminate what is merely plausible and what is ambiguously expressed, and without it he cannot methodically put questions and give answers" (Diogenes Laertius, Lives of the Philosophers VII.1.47).

"The criterion of truth they declare to be the cognitive impression" (Diogenes Laertius, Lives of the Philosophers VII.1.54). [The Stoics] assert that there are three criteria—knowledge and opinion and, set midway between these two, cognition; and of these knowledge is the unerring and firm cognition which is unalterable by reason, and opinion is weak and false assent, and cognition is intermediate between these, being assent to a cognitive impression; and a cognitive impression, according to them, is one which is true and of such a kind as to be incapable of becoming false. And they say that, of these, knowledge subsists only in the wise, and opinion only in the fools, but cognition is shared alike by both, and it is the criterion of truth.

Notes on the Text

• This is a good summary of the main points in Stoic epistemology.

• Against the Logicians I.257

[A cognitive impression] being plainly evident and striking, lays hold of us, almost by the very hair, as they say, and drags us off to assent, needing nothing else to help it to be thus impressive or to suggest its superiority over all others. For this reason, too, every man, when he is anxious to cognize any object exactly, appears of himself to pursue after an impression of this kind—as, for instance, in the case of visible things, when he receives a dim impression of the real object. For he intensifies his gaze and draws close to the object of sight so as not to go wholly astray, and rubs his eyes and in general uses every means until he can receive a clear and striking impression of the thing under inspection, as though he considered that the credibility of the cognition (τὴν τῆς καταλήψεως πίστιν) depended upon that.

Notes on the Text

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• Against the Logicians I.432

[If] only the wise man speaks the truth and possesses firm knowledge of the truth, it follows that, since up till now the wise man has proved undiscoverable, the truth also is necessarily undiscoverable; and because of this, all things are non-graspable (ἀκατάληπτα), seeing that we all, being fools, do not possess a firm grasp [or: cognition] of existent things (οὐκ ἔχομεν βεβαίαν τῶν ὄντων κατάληψιν).

• Against the Ethicists 183

[A]ccording to the Stoics the cognitive impression is judged to be cognitive by the fact that it proceeds from an existing object and in such a way as to bear the impress and stamp of that existing object; and the existing object is approved as existent because of its exciting a cognitive impression.

Stobaeus. John of Stobi. 5th century CE

Stobaeus compiled an anthology of extracts from philosophers for the education of his son, Septimius. Book II begins with "The views of Zeno and the rest of the Stoics about the ethical part of philosophy" (II.7.5-12). The source may be Arius Didymus (active in the time of the Roman emperor Augustus, 63 BCE-14 CE).

"The Stoics say that all impulses are acts of assent, and [although there are other kinds of assent,] the practical ones also contain motive power. Acts of assent and impulses differ in their objects: propositions are the objects of acts of assent, but impulses are directed toward predicates contained somehow in the propositions" (2.88.2-6).

Notes on the Text

This one of the few surviving reports about how the Stoics understood impulsive impressions.