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 A Dictionary of English Philosophical Terms  Francis Garden


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Introductory Paragraph

Early Ionic Natural Philosophers

The Pythagoreans

The Eleatics


Later Natural Philosophers

General Character of the First Period in the History of Greek Philosophy

The Sophist


The Followers of Socrates

The Lesser Socratics

Plato. Life. Works

Plato. Philosophy

The Disciples of Plato

The Old Academy

Aristotle: Life and works

Aristotle: Theory of Knowledge

Aristotle: Metaphysics

Aristotle: Physics

Aristotle: Psychology

Aristotle: Practical Philosophy

Aristotle: Rhetoric and Poetic

Aristotle: Sources

Aristotle: Unity of Plato and Aristotle

Aristotle: result

The Peripatetic School

Three Leading Post-Aristotelian Schools

The Stoics and Stoicism

The Epicureans and Epicureanism

The Sceptics

The Common Ground of the Stoics, Epicureans, and Sceptics

Philosophy in Rome: Eclecticism

The Later Peripatetics

The Later Academics

The Later Stoics

General Character of the Second Period

Standpoint and Schools of the Third and Latest Period of Greek Philosophy

Jewish-Alexandrian School


The Eclectic Platonist

Neo-Platonism. Plotinus

Neo-Platonism. Porphyry. Jamblichus

Neo-Platonism. Proclus




B. C. BURT (1852-1915) - Table of contents                        




§ 5 - The Later Natural Philosophers

The speculations of Heraclitus, the Eleatics, and earlier philosophers, established, practically, certain fundamental points for the philosophers whose views we have next to consider and who may be called the Later Natural Philosophers or Nature-Philosophers. One point was, that there is no absolute change, no real "generation" or "decay": ex nihilo nihil fit. Another point was, that there is a becoming, nature is a process.


  A third point, which may be regarded as the (imperfect) synthesis of the two, was that the process of nature is a mechanical process. In place of the monism of the earlier theorists, we shall, accordingly, find a more or less distinct dualism, of matter and force, of the material world and reason. Speculation now practically turns upon the inquiries, What causes and maintains the process of nature? What is the character and end of that process? Of these Later Nature-Philosophers, the chief are Empedocles, Anaxagoras, Leucippus, and Democritus.

Life of Empedocles

Empedocles was a native of Agrigentum in Sicily, and lived circa 495-535 B.C. He took the active interest usually taken by the early Greek philosophers in political affairs, and was a leader of the democratic party in his native city. He was not only a statesman and a philosopher, but an orator, a poet, a physician, a prophet, and a thaumaturgist. His character and personal influence are said to have been similar to those of Pythagoras.

Theory of Nature

Holding fast to the Eleatic idea that generation and decay are impossible, he yet holds, in a certain way, to the notion of Becoming; and attempts to account for changing nature by the hypothesis of a continued process of combination and separation of certain (supposed) original, imperishable, unchangeable, purely material elements or "roots," —fire, air, water, earth. Fire, air, and water, it has been seen, had been separately posited as "principles" by earlier philosophers. Empedocles was the first who assumed these four as the primal elements. Now the question arises —and this is the first appearance of such a question in the history of Greek philosophy— What is the cause of the combination and separation of the elements? The elements we have just seen are purely material; the combining and separating forces are Love and Hate, —the ancient mythological analogues of the modern scientific "attraction" and "repulsion". By Love the elements are bound indistinguishably together in one all-embracing sphere; Hate penetrating from the outside to the centre drives the elements asunder, thus giving rise to the world of individual existences. In the eternal process of nature, Love and Hate alternately rule. Variety in the world of individual existences arises, of course, from variety in the combination of elements: flesh and blood, for example, are composed of the four elements united in equal proportions, whereas bones are one-half fire, one-fourth earth, and one-fourth water. Animals are formed by the combination by Love of parts that existed separately, having sprung out of the earth. The monstrosities that were the result of the earliest combinations, such as bodies of men united to horses heads, bodies of oxen with human heads, etc., gradually gave way to higher forms, until eventually the present mode of generation was established. Empedocles, it thus appears, was, like Anaximander, an "evolutionist".

Theory of Knowledge

Even knowledge is explained by Empedocles as the result of mixture. Sense-perception is the effect of an efflux of particles from external bodies entering pores corresponding in size to them, in the body of the percipient. In the case of sight there is a double efflux, —an efflux from the eye as well as from the body perceived, sight being a consequence of the intermingling of effluences (1). The efflux from the eye is an efflux of particles of water and fire. The elements in things are known through like elements in us, —earth through earth, water through water, etc. Thought also depends, for its character, on the character of the mixture of elements. Quickness and acuteness of perception and thought result from mixtures different from those from which their opposites result. The psychological organ of truth is not perception but reflection.


The sources and essential character of the theory of Empedocles are apparent. Conceptions borrowed from, or suggested by, the Eleatics, Heraclitus, and earlier speculators, are combined to produce what is almost a purely mechanical explanation of natural phenomena. The system is mechanical because of the want of organic conception or affinity between the posited original elements and powers of nature. But for the anthropomorphic elements, Love and Hate, the system would be entirely mechanical. We may reasonably expect to encounter in the history of early Greek speculation a system from which such anthropomorphic elements are entirely absent (2).

Life of Anaxagoras

Anaxagoras was a native of Clazomenæ in Asia Minor. Though born somewhat earlier than Empedocles he flourished a little later. Giving up wealth and social position for philosophy, he went in early manhood to Athens, and remained there, as thinker and teacher, till near the close of his life, a period of about fifty years. His sojourn at Athens was the beginning of that magnificent course, hereafter to be delineated, which philosophy ran there in the most capacious intellects of antiquity. Parmenides and Zeno may have visited Athens, but Anaxagoras was the first philosopher who made that city of culture and individuality his home and the chief outward abode of philosophy. His presence in Athens during the period of her greatest glory under the statesmanship of his personal friend (and disciple), Pericles, was, no doubt, opportune for philosophy, and particularly for a system that placed in the forefront of the universe νούς, or intelligence. Among the pupils of Anaxagoras there were —besides Pericles— Euripides and Socrates. Because of the unpopularity of his doctrine —he was accused of atheism— and his connection with Pericles, he was obliged, when the latter fell temporarily into disfavor with the Athenian populace, to pay a fine and leave Athens. He died at Lampsacus on the Hellespont, 428 B.C., at the age of seventy-two. He wrote a work entitled On Nature.

Theory of Nature

To account for the order and beauty of the world Anaxagoras assumes two principles, one material, the other spiritual or quasi-spiritual. The material principle is an infinite medley, a chaos, of an infinite number of qualitatively different elements, which he terms σπέρματα, or the "seeds" of things. The elements, however, must, though different, be conceived as organically the same; i.e., each element must have in it, potentially, all others, for we cannot conceive the union of things absolutely different. The spiritual, or quasi-spiritual principle is just the opposite in nature to the material —perfectly "unmixed" and "pure," the "finest and purest of all things," an independent, intelligent power, since we cannot conceive order and beauty as the offspring of mere necessity or chance. Out of the original mixture, or chaos, the world was formed by a rotatory motion produced by the action of the original mind, a movement which, beginning at a single point and gradually extending, caused a universal separation of unlike, and union of like, seeds, the dense and moist moving to the centre, the rare and warm to the circumference of the world. This process of differentiation goes on forever, becoming ever more refined. Differences in bodies result from differences in the character of the seeds that predominate in their constitution. From the hypothesis that certain substances, e.g., gold, blood, bones, were formed only of seeds like themselves, the name homœomeriæ (όμοιομέρειαι = like parts) was applied by later writers (not by Anaxagoras) to the original elements, or "seeds" of things. The earth he conceived to be a cylinder resting on the air, in the centre of the universe. The sun is not a blessed god, as the multitude believe, but an immense glowing mass of stone —as large as the Peloponnesus, —one of the doctrines, probably, that gave ground for the charge of atheism that was brought against him. The moon is like the earth and is inhabited. Plants and animals spring from germs communicated to moist or slimy earth by the air and the æther; they have souls, and feel pleasure and pain.

Theory of Mind or Nous (νούς) and of Knowledge

The world-mind has been described as a nature that is perfectly "pure" and "unmixed," "the finest and purest of all things," and independent of the material universe. All derivative minds are essentially the same with it, and with one another, differing from it and from one another only in degree. Sense-perception, which is dependent upon the structure of the bodily organs, is not of "like by like," as Empedocles asserted, but of "like by unlike," as of heat by cold: that which is equally warm with ourselves makes no impression upon us. The senses do not afford real knowledge; that comes through reason. Man's highest satisfaction lies in the pursuit of wisdom.


The mechanicalness that is so conspicuous in the theory of Empedocles is less conspicuous here; for there is, in the very essence of the "principles" of the system —the "seeds," which, though different, are potentially the same and virtually synthesizable, and the world-ordering mind—, the beginning of an organic conception of the universe. For if chaos be a mass of potentially organizable, though not actually organized or articulated elements, it just verges upon mind, which is the actually determining, organizing element in the universe. The system of Anaxagoras is mechanical, therefore, in part because it offers no statement of this connection between matter and mind. For another reason, also, it fails of being organic and completely rational, viz., Anaxagoras's conception of mind was, though fundamentally correct, but rudimentary. A developed conception of mind belongs, in fact, to a later period in the history of thought. Plato and Aristotle, the latter of whom, comparing him with other nature-philosophers, likened him to a sober man coming in among the drunken, properly enough found fault with the theory of Anaxagoras, because in it mind was treated as a mere mover of matter. Anaxagoras, as Plato points out in his dialogue Phœdo (pp. 97-99), just missed grasping fairly the idea of the final cause, or of end-determined causation, in nature.

Leucippus and Democritus, the Atomists; their Lives

Of Leucippus's life nothing is known. He was the originator of the essentials of the theory expounded in the writings of Democritus, who was a pupil of his. Democritus was born in Abdera in Thrace about the year 460 B.C. Possessed of great wealth, he was able to gratify to the fullest extent his passion for knowledge, which impelled him to travel very extensively in Egypt and the East, and, upon his return home, to devote himself to philosophical research. He was the most learned of the early Greek philosophers, an encyclopædist, worthy of the admiration freely bestowed upon him by the still greater master of knowledges, Aristotle. His numerous works, of which only fragments have been preserved, were written in prose instead of didactic verse, such as most of his predecessors had employed. They were greatly admired among the ancients for their style as well as their doctrine. Democritus lived about a century.

Theory of Nature

Μή μάλλον τό δέν ή τί μή δέν εϊναι: "No more is Thing [Being] than no-Thing [not-Being]," says Democritus, recognizing the respective claims of the Eleatics and Heraclitus. This implies that Democritus accepted, and attempted to explain, change as a fact. To do the latter, he conceived Being to consist of innumerable eternal, infinitesimal, movable, material elements, which he termed άτομα (indivisibles), i.e., atoms. With Being thus constituted (termed the "full," "plenum") is coeval not-Being, empty space (the "void"). Thing and no-Thing, the "full" and the "void" constitute absolute reality: all else is phenomenal. Unlike the four elements of Empedocles and the seeds of Anaxagoras, they are not qualitatively, but only quantitatively, different, —different as regards figure, size, weight, order, and position. The world of individual existences is produced by the eternal falling (!) and collision of the atoms, due to an inherent necessity. By a rotatory motion thus generated the heavenly bodies were produced. The qualitative as well as quantitative properties of things depend merely upon the figure, size, weight, arrangement, position, and number of the atoms constituting them. Though atoms are imperishable, the bodies composed of them are not.

Theory of the Soul, of Knowledge, and of the Good

Soul, or spirit, in the external world and in man, is composed of fine, round, smooth, fiery atoms. The exhalation and inhalation of these is the source of life in the human body. In the brain the motion of such atoms produces thought, in the heart anger, in the liver desire. Sense-perceptions are the effects of impressions made upon the organs of sense by particles of air set in motion by effluences from objects. The sensation of sight, however, is a resultant of the meeting of emanations from the eye with incoming impulses. Dreams are effects of enfeebled and distorted images (εϊδωλα) that have found their way from objects and persons to our minds. The character and degree of trustworthiness of sense-perceptions depend upon the character of external impressions. Sense gives conflicting reports and is deceptive. Thought, which is a result of a symmetrical motion of atoms, is alone the source of knowledge. The true method in knowledge is to proceed from the known to the unknown. Ethically considered, man's real being lies in nobility of soul: his real good is happiness, which is not sensuous enjoyment but peace and contentment springing from measure and moderation in living. The highest happiness is the pleasure of knowledge. The seat of morality is not in the act performed but in the will. Democracy is the best form of government. The wise and good are citizens of the whole world. The popular gods are beings in the air similar to man but far higher in degree. The truly divine element in the world is the fiery atom or totality of fiery atoms (3).


The theory of the Atomists is doubtless the most perfect of the merely mechanical, non-anthropomorphic (4), theories of nature of the early Greek philosophers: it has a simplicity and an inner consistency not possessed by any other. The conceptions of quantity and natural necessity, which are the ruling conceptions of the theory, are harmonious and easily grasped, and seem all-sufficient, until problems of soul and life are confronted, when it becomes necessary to recognize mind as an absolute. The Atomists are unable to derive, theoretically, knowledge and feeling from the nature and motion of atoms, and the conception of natural necessity is poor in content compared with that of mind. This being the case, while in one direction the Atomistic philosophy is the most highly developed of all the early nature-philosophies, the philosophy of Anaxagoras is, on the whole, nearer the truth: the philosophy of nature is naturally and necessarily linked with that of mind. It should be noted before leaving Democritus that he entered more largely than did any of his predecessors into anthropological and ethical questions, topics belonging to the philosophy of man as distinct from merely physical nature. In this respect he has greater affinity with the philosophers of the next period than any of the very early Greek philosophers.


(1) In modern "psychological" phraseology this would mean that sight is both "objective" and "subjective".

(2) See p. 32 infra.

(3) See Zeller's Pre-Socratic Philosophy, Vol. II. pp. 207-321.

(4) See supra, p. 26.



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