Sources. All the writings of the earlier Stoics, with the
exception of a few fragments, have been lost. We possess, indeed, the
complete works of the later Stoics, -- Seneca, Epictetus, Marcus
Aurelius, Heraclitus, and Cornutus; but these philosophers
lived under the Roman Empire, at a time when foreign influences had
substituted new elements for the doctrines which had been
characteristic of the school at the beginning of its existence. We are
obliged, therefore, to rely for our knowledge of early Stoicism on
writers like Cicero, Plutarch, Diogenes Laertius, Sextus
Empiricus , and the Aristotelian commentators, who, however, do not
always distinguish between the earlier and the later forms of Stoicism.
Consequently, it will be found more satisfactory first to give a
history of the Stoic school, and then to describe the Stoic doctrine as
a whole, without attempting to determine the contributions made by
individual members of the school.
History of the Stoic School. (a) Greek Stoics. Zeno of
Cittium (350-258 B.C.), the founder of the Stoic school, was born
at Cittium in Cyprus in the year 350 B.C. He was at first a merchant,
but owing, it is said, to a shipwreck in which he lost a considerable
part of his wealth, he repaired to Athens with the intention of
pursuing the study of philosophy. On reading the Memorabilia of
Xenophon and the Apology of Plato, he was impressed with the
remarkable character of Socrates, and was led to attach himself to the
school of Crates, the Cynic, who appeared to reproduce in his own life
and manners the character of the sage. Later on, repelled, no doubt, by
the coarseness and vulgarity of the Cynics, he became successively
disciple of Stilpo, the Megarian, and of Xenocrates, the ruler of the
Academy. About the year 310 B.C. he founded a school of his own, which
reason of his habit of teaching in the Painted Porch (Stoa) came
to be known as the Stoic school. He reached an advanced age and,
according to account given by Diogenes and others, ended his life by
suicide. His writings have all been lost.
Cleanthes succeeded Zeno as master of the Stoa. He is said to
have been originally a pugilist. Zeno characterized the mental
temperament of Cleathes by comparing him to a hard slab on which it is
difficult to write, but which retains indefinitely whatever is written
on it. True to this description, Cleanthes preserved the teachings of
his master, but showed himself incapable of expanding them into a more
He is the reputed author of a Hymn to the Most High, preserved
by Stobaeus. 
 Cf. Zeller's Stoics, etc., p. 41, n.; Ritter and
Preller, op. cit., p. 394, note e.
Chrysippus, who succeeded Cleanthes, was born at Soli, in
Cilicia, in the year 280 B.C. He was more original than Cleanthes, and
under his direction the Stoic school reached its full development.
Among his disciples were Zeno of Tarsus, Diogenes of
Seleucia, and Antipater of Tarsus, whose pupil,
Panaetius (180-111 B.C.), introduced Stoicism into the Roman
(b) Roman Stoics. Among the Roman Stoics the best known are
L. Annaeus Cornutus (A.D. 20-66), M. Annaeus Lucanus
(A.D. 39-65), Seneca the younger (A.D. 3-65), Persius,
the satirist (A.D. 34-62), Epictetus, the philosopher-slave
(flourished A.D. 90), and the Emperor Marcus Aurelius (A.D.
It is a fact worthy of note that Cleanthes, Seneca, and Lucan committed
suicide in accordance with what as we shall see was one of the ethical
doctrines of the school, imitating in this the example of the founder.
General Idea of Stoic Philosophy. The Stoics evidently
considered themselves the true disciples of Socrates, and it was,
without doubt, from Socratic principles that they deduced their idea
of the aim and scope of philosophy. We have seen that Zeno was
first led to philosophy by the hope of finding in it consolation for
the loss of his temporal goods, and when he came to establish his
school he took for his starting point the Socratic doctrine that
knowledge is virtue, making the pursuit of knowledge (philosophy) and
the cultivation of virtue synonymous. When, however, the Stoics set
about discovering a systematic basis for their ethical
teachings, they went back to pre-Socratic systems, and drew largely
from the physical doctrines of Heraclitus. Now, there were two tenets
in the Heraclitean philosophy which recommended themselves in a special
manner to the Stoics: (1) that all individual things are but the
ever-changing manifestations, or apparitions, of the ever-enduring
fire, and (2) that there is but one law, which governs the actions of
men, as well as the
processes of nature. Consequently, the Stoics made these principles
the foundation of the science of human conduct. At the same time they
did not hesitate to supplement the physics of Heraclitus by borrowing
from Aristotle's physical doctrines. They were influenced, too, by
Antisthenes' nominalism and by his opposition to the Platonic theory
of Ideas, and in their theological doctrines they made use of the
Socratic and Platonic teleology. All these elements they amalgamated
into a consistent system. Logic and physics they made subservient to
ethics, on the principle that the theoretical should be subordinated
to the practical.
We have, therefore, three divisions of Stoic Philosophy. (1)
Logic, including the theory of knowledge; (2) Physics,
including theology; and (3) Ethics, the hegemonic science.
Stoic Logic. It was probably Zeno who first gave to logic the
name by which it is now known, though this is by no means certain. The
logic of the Stoics was simply the Analytic of Aristotle
supplemented by a more adequate treatment of the hypothetical
syllogism and by the addition of the problem of the criterion of
truth. To the latter question they devoted special attention, and, in
their solution of it, developed the Stoic theory of knowledge.
Theory of knowledge. 1. The Stoics start with the Aristotelian
principle that all intellectual knowledge arises from sense perception.
Sense-perception (aisthÍsis) becomes
representation, or imagination (phantasia), as soon as it
rises into consciousness.  During the process of sense-perception the
soul remains passive, the object producing its image on the mind, just
as the seal produces its impression on wax. The process was, therefore,
called tupŰsis, although Chrysippus is said to have
substituted the word heteroiŰsis, alteration of the
soul.  When the object of knowledge is removed from the presence of
the senses, we retain a memory of it, and a large number of memories
constitutes experience (empeiria).
 Placita, IV, 12; Diels, op. cit.,
 Sext., Mathem., VII, 228.
2. The next step is the formation of concepts. Concepts are
formed either (a) spontaneously, that is, when, without our
conscious cooperation, several like representations fuse into universal
notions (prolÍpseis, or koinai ennoiai); or (b)
consciously, that is, by the reflex activity of the mind, which
detects resemblances and analogies between our representations, and
combines these into reflex concepts, or knowledge
(epistÍmÍ). Neither spontaneous nor reflex concepts
are, however, innate; spontaneity does not imply innateness.
3. As, therefore, all our knowledge arises from sense-perception, the
value to be attached to knowledge depends on the value to be attached
to sense-perception. Consequently, the Stoics decided that
apprehension (katalÍpsis) is the criterion of
truth. That is true which is apprehended to be true, and it is
apprehended to be true when it is represented in the mind with such
force, clearness, and energy of conviction that the truth of the
representation cannot be denied.  The saying attributed to Zeno by
Cicero  that Perception is like the fingers extended, that
Assent is like the half-closed hand, that Apprehension is
like the hand fully closed, and that Knowledge (Scientia)
is like the closed hand firmly grasped by the other hand, would seem to
attribute to knowledge a superiority over sense-perception. On closer
examination, however, it is seen that the difference is only a
difference of degree. 
 Sext., Mathem., VII, 244.
 Acad., II, 47.
 Cf. Ritter and Preller, op. cit., pp. 399 ff.
4. The question, What is the value of concepts? was answered by the
Stoics in accordance with nominalistic principles borrowed from
Antisthenes, who, in opposition to Plato, taught that no universality
exists outside the mind, the individual alone being real. 
 Placita, IV, xi ; Diels, op. cit., p.400.
5. In their classification of concepts the Stoics reduced the ten
Aristotelian categories to four: (1) substance
(hupokeimenon), (2) essential quality (to poion),
(3) accidental quality (pŰs echon),
and (4) relation (pros ti pŰ s echon).  This
enumeration, as will be readily perceived, does not retain the
Aristotelian distinction between predicables and categories. All the
Stoic categories, except the first, are modes of predication rather
than modes of being.
 For authorities, cf. Ritter and Preller, op. cit., p.
Stoic Physics and Theology. The physics of the Stoa is a system
of materialistic monism, while the theology of the Stoa may be
described as a compromise between theism and pantheism.
The Stoics maintained that the material alone is real. They
would not admit, for example, that the soul, or virtue, is real except
in so far as it is material. God Himself they believed to be material.
Above all the categories, therefore, they would place not on,
Being, but ti, something, a transcendental notion
including not-Being as well as Being, the incorporeal as well as the
corporeal. Thus did they identify the incorporeal with the unreal, and
include all real being under the generic concept of matter. 
 Cf. Seneca, Ep. 58.
Consistently with these principles the Stoics teach that all attributes
are air currents: emotions, concepts, judgments, virtues, and vices are
air currents which either pass into the soul or come out from it.  In
extenuation of this crude materialism, it must be remarked that the
Stoics distinguish between a finer and a coarser matter, attributing to
the former an active and to the latter a passive character. The air
currents are in substance material; in function, however, they are
active, and may be said to play a rŰle similar to that which the
form plays in Aristotelian philosophy. 
 For references, cf. Zeller, Stoics, etc., p. 127,
n.; cf. als o Ritter and Preller, op. cit., p. 408, note
 Cf. Ritter, History of Ancient Philosophy, trans. by
Morrison (Oxford, 1838), Vol III, p. 513; also Benn, The Greek
Philosophers , Vol. II, p. 13. The latter says:" Virtues and vices
were, according to the Stoics, so many gaseous currents by which the
soul is penetrated and shaped -- a materialistic rendering of Plato's
theory that qualities are distinct and independent substances."
Everything, therefore, is material: the common distinction between
corporeal and incorporeal is merely a distinction between coarser and
finer matter. We may, indeed, distinguish two principles, or sources,
of reality, -- matter and force, -- but we shall find that in
ultimate analysis force, too, is material.
God is, at once, the Author of the universe and its Soul, -- the
immanent principle of its life; for every kind of action ultimately
proceeds from one source, which, whether it resides in the heavens or
in the sun or in the center of the world (on this point the Stoics were
not agreed), diffuses itself throughout every part of the universe, as
the cause of heat and growth and life and motion.
God is at one time described as Fire, Ether, Air, Atmospheric
Current (pneuma); at another time as Soul, Mind,
spermatikos); while sometimes both styles of phraseology are
combined, and He is called the Fiery Reason of the World, Mind in
Matter, Reasonable Pneuma. The language of compromise is
never wholly consistent, and the Stoic theology is an attempt to
compromise between theism and pantheism. It is, however, certain
that the Stoics conceived God to be something material; for in their
explanation of the presence of God in the universe they assume that the
universal intermingling (krasis di holŰn) implies the
impenetrability of matter, so that even when they call Him Mind, Law,
Providence, Destiny, they understand by these terms something
 Cf. Cicero, De Nat. Deorum, II, 7 ff.; ibid., I,
God and the world are the same reality, although there exists a
relative difference between God, or reality regarded as a whole, and
the world, or reality considered in some one or other of its aspects.
This pantheism is the central doctrine of the Stoic physics;
indeed, it may be said to be the inspiring thought which justified to
the Stoic mind the study of natural phenomena. For the Stoics, as has
been said, looked upon philosophy as primarily a matter of practical import, and studied physics only in
order to find a basis for their ethical speculations. Such a basis they
found in the doctrine of pantheism. This doctrine may, therefore, be
said to have been their religion as well as their philosophy.
Accordingly, they criticised the popular beliefs of their time, being
careful, however, to admit whatever elements of truth they found in
polytheistic religion, and making free use of allegory as a means of
bridging over the chasm between polytheism and pantheism.
 Cicero, De Nat. Deodrum, III, 24ff.
We may, therefore, speak of the world as the body, and of the
Deity as the soul of the universe, if we are careful to bear in
mind that the distinction is merely a relative one. The world
arose in the following manner. The primal fire was condensed into
air and water; water in turn was condensed into earth The derived
elements are constantly tending to return by rarefaction to the primal
fire;  but no sooner will this destruction by conflagration have
taken place than the primal fire will issue forth in another series of
condensations, thus beginning another cosmic period, which will end
like its predecessor in conflagration. Here the influence of Heraclitus
 Stob., Ed., I, 444; Diels, op. cit., p. 465.
The Deity, regarded as the origin of these processes of condensation
and returning rarefaction, -- the primal fire, -- is logos
spermatikos regarded as the ruling or guiding principle of these
processes, He is Providence (pronoia) and Destiny
(eimarmenÍ). For all things come forth from the primal
fire according to law, and all the subsequent changes in the world, all
the events of human history, take place according to the necessary
sequence of cause and effect. When we think of the order and
intelligent arrangement of the divine government, we name the Divine
Ruler Providence; when we think of the necessary dependence of
effect on cause, we name Him Destiny or Fate. 
According to the Stoic conception, Providence is
directed immediately to the processes of the universe in general and
only mediately to the individual and his actions.
 Diog. Laer., VII, 149.
In support of their doctrine of Providence, the Stoics appeal to the
universal consent of mankind,  being, apparently, the first to
use this argument.
 Stob., Ecl., I, 100.
The human soul is material. This not only follows from the
general principles of Stoic philosophy but is also expressly taught by
the Stoics and proved with the aid of many arguments. The soul is
conceived as fiery breath (pneuma) diffused throughout the body;
in fact, the relation of the soul to the body is the same as that of
the Deity to the world. It is, in a special sense, part of the Deity,
partaking more and more of the nature of the Deity according as we
allow greater play to the divine, or reasonable, in us. Now, it is
precisely on account of this special proximity of the soul to the
divine that it cannot escape the necessity which divine law
imposes on all things. The soul is in no sense free, unless it be
said to be free because the necessity by which it is ruled comes from
its own nature rather than from anything external to it. Merit and
reward follow the action which, although it must be performed, is
performed voluntarily, that is, with perfect acquiescence in the rule
of divine destiny. "Volentem fata ducunt; nolentem trahunt."
 Diog. Laer., VII, 157.
 Seneca, Ep. 31.
 Cf. Cicero, De Fato, XVIII.
The Stoic idea of the soul is as incompatible with immortality
as it is with the freedom of the will. The soul, being material, is
destined to destruction. The time, however, at which the soul is to be
dissolved into the primal fire is not the moment of death, but the end
of the cosmic period, when all matter is to be destroyed by
conflagration. The Stoics were divided as to whether the souls of all
men, or only those of the wise, will last until that time.  Seneca's
reference  to death as the birth of a future life, and his
description of the peace that awaits the
soul beyond the grave, suggestive as they are of Platonic and,
possibly, Christian influences, contain nothing that is at variance
with what the Stoics taught about the destiny of the human soul.
 Diog. Laer., VII, 256.
 Ep. 102.
Stoic Ethics. The Stoics regarded ethics as the "divine part" of
philosophy, from which, as from a center, all their logical and
physical inquiries radiate. Questions of logic and physics were of
interest merely in so far as their solution threw light on the
paramount problem of philosophy, the problem of human destiny and human
happiness. Thus, at the very outset of the ethical inquiry concerning
happiness, the Stoics applied the most characteristic of their physical
doctrines, -- that everything in the world of reality obeys and must
obey inevitable law. Man, it is true, is endowed with reason, and is
thereby enabled to know the law which he obeys; he is none the less
obliged to obey it. Nay, more, since he is in a special sense divine,
he is under greater necessity to obey than other manifestations of the
Divine. The supreme canon of conduct is, therefore, to live conformably
to nature (homologoumenŰs tÍ phusei zÍn), or,
as Zeno is said to have formulated the maxim, to live a consistent
life, homologoumenos zÍn. This is man's happiness
(eudaimonia), his chief good (agathon), the end of his
existence (telos). 
 Cf. Cicero, De Finibus, III, 5; Diog. Laer., VII,
The highest purpose of human life is not, therefore, contemplation, but
action in accordance with the laws of universal nature, with the will
of the Deity. A hint of this purpose is contained in the instinct of
self-preservation which is the primary impulse in every being.
Action in accordance with nature's laws is virtue, which Cicero
translates recta ratio. Virtue is not merely a good; it
is the only good. Consequently, riches and pleasure and health
and honors are not goods in any true sense of the word; and the Stoics
persistently combated the teaching of Plato and Aristotle, who
considered that the external goods of life are worthy of
being desired, although they are subservient to the chief good, which
is virtue. Stoicism was still more decided in its opposition to the
Hedonist doctrine which made virtue itself to be a good subordinate to
 Diog. Laer., VII, 30; Marcus Aurelius, IX, 16.
Tf, then, virtue is the only good, it must be sought for its own
sake; it contains all the conditions of happiness; virtue is
virtue's own reward.  Everything else is indifferent
 Diog. Laer., VII, 102; Seneca, Ep. 85.
The Stoics adhered to the Socratic doctrine that virtue is one, and
yet, since virtue, while one, may have a plurality of objects, they
considered that there are different manifestations of virtue, such as
prudence, courage, temperance, and justice (which Plato regarded as
four kinds of virtue), and patience, magnanimity, etc., which may be
regarded as derivations from one or other of the cardinal virtues.
Accordingly, a man who is prudent must of necessity be courageous; for
he who possesses one virtue must possess all. Now, he who has
a right appreciation of good and evil, and who consequently intends to
do good, is virtuous. From which it follows that no act is in itself
praiseworthy or reprehensible; the morality of the act is determined by
the disposition: "Non quid fiat, aut quid detur refert, sed qua
 Stob., Ed., II, 204.
 Cicero, Paradoxa, 3, 1.
 Seneca, De Beneficiis, VI, 6.
Vice, the opposite of virtue, consists in living out of harmony
with the laws of nature. Like virtue, it is essentially one. He who is
guilty of one vice is guilty of all; there is no distinction of degree
in vice. ("Omnia peccata paria.")
The Stoics, however, although they seemed to identify moral excellence
with intellectual or rational insight, and spoke of the virtuous man as
the wise man, recognized that man is not wholly rational. From his
irrational nature spring the emotions (pathÍ). The
emotions -- perturbationes, as Cicero calls them -- are movements
of the mind contrary to reason.  Now, there is
a desire (hormÍ) which is according to law and reason,
and this is the natural impulse towards what is good. The desire, on
the contrary, which is according to emotion is intrinsically
unreasonable and therefore bad; for all emotions are contrary to
reason. It follows that the wise man should aim at eradicating all his
emotions; he should strive to become absolutely emotionless.  This
doctrine of apathy is one of the most characteristic of the
doctrines of the Stoa. 
 Diog. Laer., VII, 120,
 Diog. Laer., VII, 117.
 For comparison of the Christian and the Stoic systems of morality,
cf. Talamo, Le origini del Cristianesimo e il pensiero
stoico (terza ed., Roma, 1902).
In their application of these ethical principles the Stoics developed a
vast number of paradoxes referring to the wise man, that is, to
the ideal Stoic philosopher. He alone is free, beautiful, rich, and
happy. He alone knows how to govern as well as to obey. He is the
orator, the poet, the prophet. The rest of the world is mad; the
majority of men pass their lives in wickedness, slaves to custom, to
pleasure, and to a multitude of desires. The wise man alone is
indifferent to pain; for him death has no terrors, and when he is
called upon to decide between death and dishonor he is true to his
Stoic teaching if he prefers the former. Suicide, therefore, is
sometimes a duty; it is always justified if impending misfortune is
such as seriously to threaten peace of mind and tranquillity of soul.
The wise man is independent of all ties of blood and kinship. He is at
home everywhere. He is a citizen of the world, or, as Epictetus
says, he is a child of God and all men are his brethren.
 Dissertations, I, 23, 3.
Historical Position. Stoic philosophy, by reason of its
systematic development, approaches more closely to the
comprehensiveness of the Platonic and Aristotelian systems than does
any other philosophy of this third period. Taking up the best
principles of the Cynic morality, it advanced far beyond the Cynic
philosophy, owing to the larger part which it assigned
to mental culture in its scheme of life, and also to the broader and
more systematic basis of logic and physics on which it built its
ethical teaching. Nevertheless, Stoicism is not free from the dominant
vice of the age to which it belonged. It is a one-sided development
of philosophy. It subordinates the theoretical to the practical. In
its theory of knowledge it is sensistic; in its physics it is
materialistic and pantheistic; in the development of its moral
principles it subordinates the individual to universal law, stamping
out individual desire, and advocating the merging of domestic and
political instincts in a far-off dream of the fellowship of
cosmopolitan philosophers. It lacks that comprehensive sweep of
contemplation which, in the golden age of Greek philosophy, set the
theoretical by the side of the practical, placed the study of nature on
a footing which gave it a value of its own, distinguished, without
separating, matter and mind, and in ethics gave due importance to the
individual emotions and to the social instincts as well as to the
immutable moral law. This disintegration of the universal philosophical
view, and the consequent isolation of separate aspects of speculative
and practical problems, which is first seen in Stoicism, goes on
increasing in the systems which come after the philosophy of the Stoa.
Of all the defects of Stoicism, that which contributed most to the
downfall and dissolution of the school was the doctrine that the wise
man is emancipated from all moral law. This doctrine is not the only
tenet of the Stoics which recalls the philosophy of the Orient rather
than that of Greece. The identity of God and the world, the emanation
of the soul, the final reabsorption of all things in God, -- these
and similar doctrines are peculiar to the Oriental form of speculation.
We must remember that Zeno of Cyprus was not more than half Greek, and
although his mental training and the logical derivation of his
philosophy were entirely Greek, there was in him enough of the Oriental
temperament to infuse into his philosophy a spirit more in accordance
with the quietism of the East than with the Grecian
sense of artistic completeness. This quietism, together with the
exorbitant claims set up on behalf of the wise man, finally brought
Stoicism down to so low a level of moral aims that it was scarcely to
be distinguished from Epicureanism.