Strato of Lampsacus

Strato of Lampsacus (335 – c. 269 BC) was a Peripatetic philosopher, and the third director (scholarch) of the Lyceum after the death of Theophrastus. He devoted himself especially to the study of natural science, and increased the naturalistic elements in Aristotle's thought to such an extent, that he denied the need for an active god to construct the universe, preferring to place the government of the universe in the unconscious force of nature alone.

Very little is known of Strato’s life. His father was Arcesilaus. His birthplace, a small town on the Asian coast of the Hellespont (Dardanelles), had a certain tradition of philosophical studies: Anaxagoras (d. ca. 428 b.c.) spent his last years there and may have founded a school, and Epicurus taught there for some years before founding his school at Athens in 306 b.c. Thus the first impulse to scientific work may have come to Strato in his native town. The dominant influence on his thought was that of Aristotle’s school at Athens. It is not known when he joined it, but he must have spent a considerable time studying there under Theophrastus; it is just possible, but unlikely, that Aristotle was still at Athens when he entered. The next known event in Strato’s life was his appointment as tutor to the future Ptolemy II Philadelphus, who ruled Egypt from 283 to 246 b.c.; this implies a period of residence at Alexandria, where he may have been concerned in the establishment of the museum and perhaps met such important intellectual figures as Diodorus Cronus, the “Megarian” philosopher, and the anatomist and surgeon Herophilus. Strato seems to have maintained a correspondence with Ptolemy and his queen Arsinoë after his return to Athens. On Theophrastus’ death ca. 287, Strato was elected to succeed him as head of the Lyceum, a position he held until his death eighteen years later.

Since Strato’s writings are not extant, knowledge of his work is derived from later sources. These fall into two classes. The first consists of passages in later authors where Strato is quoted or referred to by name; they are mostly quite short and generally report his conclusions without the reasoning that led to them. The most important are in a commentary on Aristotle’s Physics by Simplicius, a Neoplatonist writing in the sixth century a.d.

The second consists of writings in which Strato is not named but which can be shown to be derived from his work. The importance of these sources is that some of them have preserved the reasoning by which Strato arrived at his theories. The most important texts of this class are the introduction to the Pneumatica of Hero of Alexandria and a long extract from a book On Sounds (Пєρί ’Aкоυσтών), wrongly attributed to Aristotle, included in Porphyry’s commentary on the Harmonica of Ptolemy (third century). They are supported by shorter texts from the pseudo-Aristotelian Problems, the Greek commentators on Aristotle, and others. The evidence in favor of attributing their contents to Strato is so strong as to make this virtually certain. Nevertheless, in the following reconstruction of Strato’s teaching, the two kinds of evidence will be distinguished as far as possible.

From an incomplete list of his books preserved by Diogenes Laërtius (5.59 ff.), we learn that Strato wrote on logic, ethics, cosmology (including meteorology), psychology, physiology, zoology, and even a book on inventions–in fact, on most of the subjects included in the Aristotelian corpus. But his interest was centered on physics, in the wide sense the ancients gave to that word–the study of the natural world in all its aspects. All his significant work was done in this field, and it is the only part of his teaching about which we have any real information. Strato’s preoccupation with this kind of work, in an age when philosophers generally were more concerned with problems of ethics and the theory of knowledge, earned him the sobriquet ό φυσικός to distinguish him from others of the same name.

Modern historians generally have represented Strato as an eclectic trying to combine elements from the systems of Aristotle and Democritus. Nothing could be further from the truth. In reality his thought was a one-sided but legitimate, consistent, and often brilliant development of Aristotle’s views, along lines that to a large extent had been marked out by Theophrastus. The occasional resemblances between Strato’s doctrine and that of the atomists are fortuitous. What Strato did was to strip the Aristotelian world picture of its transcendental elements–or, to put it another way, he refused to acknowledge the reality of anything not subject to the natural laws seen to apply in the sublunary world. In doing this he was carrying to its logical conclusion a process begun by Aristotle himself.

Aristotle had criticized Plato’s conception of a world of Forms above and behind the sensible world on the ground that he had failed to show how these two systems were related. Nevertheless, he continued to teach the existence of an Unmoved Mover outside the physical world and above its laws; and within the physical world he distinguished two systems subject to different laws, one extending from the center of the universe to the sphere of the moon’s revolution, the other embracing the heavenly bodies. The difficulties entailed by the second division can be seen by studying Aristotle’s Meterologica; those involved by the first were stated by Aristotle’s pupil Theophrastus in his Metaphysica, in which the Unmoved Mover and the teleological view of the world are subjected to a critique that in many ways is a continuation of Aristotle’s critique of the Platonic Forms.

It was left to Strato, however, to construct a new cosmology in which the world was explained as the product of immanent forces only. The ancient authorities tried to express this by saying that “everything that exists is the result of natural weights and movements”(fr. 32, from Cicero): that“all divine power is contained in nature, which contains in itself the causes of coming-into-being, growth and decay, but has no consciousness or shape” (fr. 33, from Cicero): that“natural processes are governed by ’what happens spontaneously’ (тὸ αὐμαтоν)” (fr. 35, from Plutarch); and even that Strato regarded heaven and earth as gods (frs. 37 and 39, both derived from Seneca). The preference for an explanation of the world that does not depend on transcendent causes was shared by Strato with the other chief philosophical schools of his day, the Stoics and the Epicureans; but their teaching was in some ways more naïve and less radical. Strato differed from the Stoics in denying that nature is conscious and provident, and from the atomists in positing a regulating principle to which all the processes that constitute the world are somehow subordinated.

The tendency to bring all reality under the same laws appears again in Strato’s description of the physical universe. Like Aristotle, he seems to have regarded it as unique and finite; at least we are told he believed that“void can exist within the universe, but not outside it” (frs. 54–55). But he rejected Aristotle’s doctrine of “natural places,” and said that all bodies have weight, a natural tendency toward the center of the universe (frs. 50–53); light substances move away from the center because they are“squeezed out”by the heavier. (This was also the view of the atomists and is the only point of any substance on which Strato and they agreed.) The stars are composed of fiery stuff, not, as Aristotle thought, of the mysterious“fifth substance,”and are subject to the same laws of gravitation as everything else (fr. 84); a different report, according to which Strato held that the stars derive their light from the sun (fr. 85), probably refers to the moon and planets only.

The immediate cause of physical phenomena is the interplay of natural forces, especially the traditional elementary forces hot, cold, moist, and dry; the hot had a special preeminence. Strato, like Theophrastus, tended to identify these forces with the substances in which they inhere, and treated even heat and light as material emanations (frs. 42–49, 65). Aristotle’s distinction between matter and form was blurred in theory by Strato’s argument that in any process, the starting point and end point (the formal element), as well as the substrate, are subject to movement (fr. 72; against Aristotle, Physics, 224b4), and was ignored in practice. Strato’s approach is revealed very clearly in his doctrine of animal reproduction. Aristotle had taught that the male parent contributes the active, formal principle and the female, the material principle. Since the perfection of anything depends on the dominance of form over matter, and males are more perfect than females, the offspring would be male if the (father’s) formal principle completely mastered the material contributed by the mother, female if it did not. Strato, however, held (frs. 94–95) that both parents produce“semen”(γоνή, the word used by Aristotle to denote the male active-formal principle only), and that the offspring would be male if the father’s female if the mother’s“semen”predominated; he also believed that the“power” (δύναμις) of the semen is material, being“of the nature of breath” (πνєυμαтικὴ). Thus the Aristotelian interplay of form and matter was replaced by a tug-of-war between forces, which, although opposed, were fundamentally of the same kind.

Another feature that distinguished Strato’s theory from Aristotle’s was his belief that bodies are not continuous but consist of tiny particles with void interstices where the particles do not fit together exactly. This scheme was used to account for compression and rarefaction, and for the ability of one substance to penetrate another. Material substances could act on each other only if they first interpenetrated; surface contact was not enough, in Strato’s view, to ensure a reaction. Thus the interactions of substances were determined by two factors, their dynamic compatibility and their structure. The same idea is found in some of the writings of Theophrastus; but whereas Theophrastus apparently thought that only solids have this discrete structure, Strato extended it to all bodies, including liquids and gases–even light rays, he says, must consist of particles separated by void, for they are seen to interpenetrate (fr. 65). The existence of void was, however, closely circumscribed. Hero tells us that bodies tend naturally to fill all empty space; no“continuous void”can exist naturally in the world or, as we have seen, outside it. Void interstices or“Pores”are found in nature only where the shape of the particles composing bodies does not allow them to fit together exactly. A large void can, however, be produced artificially, as when air is sucked out of a sealed container and, conversely, some bodies can be compressed, that is, their particles can be made to pack more closely into their“pores”. But both conditions are unnatural, and the bodies concerned will return to their normal state as soon as the force that produced the artificial conditions is removed. This is the famous law of horror vacui, which Hero–or, rather, the engineering school of Ctesibius, of which Hero is a late representative–took from Strato as the theoretical basis for the construction of hydropneumatic machines.

Since Strato’s admission of void has been taken as chief evidence for direct atomist influence, it is necessary to emphasize the difference between his doctrine and atomism. This can be expressed by saying that the atoms and void were the starting point of atomist physics, while the particles and interstices were the end point of Strato’s. Instead of being the eternal prime constituents of the world, Strato’s particles were mere divisions of matter, with no stable individual existence; the qualities hot, cold, moist, and dry, which Strato regarded as primary, were for the atomists epiphenomena of the shapes and sizes of atoms; the void, which for the atomists was infinite in extent and within which the atoms moved freely, existed in Strato’s world only as discrete interstices, imprisoned in matter like the bubbles in foam rubber; lastly, the Democritean atoms are in constant movement and tend to repel each other, while Strato’s particles hang closely together unless forcibly separated.

To complete the framework of his cosmology, Strato criticized and modified Aristotle’s teaching about place, time, and motion. The most fundamental change concerned the nature of place, which Aristotle had defined as the boundary at which a containing body is in contact with a body it contains (Physics, 212a6). This definition had been criticized by Theophrastus (frs. 21–22), and Strato went back to an earlier conception that Aristotle had considered and rejected: the place of anything is the hypothetical space between the extremities of that thing. Space is coextensive with the universe; qua space it is empty, but in fact all space is always filled with matter of some kind (frs. 59–60). In this definition Strato seems to have disregarded the existence of void interstices in bodies, presumably because he considered them as part of the substances in which they occur. In regard to motion and time he made only minor changes. He emphasized the continuity of both and the uniformity of time, and stressed that time is a concomitant of physical things, not an independently existing reality. He also seems to have replaced Aristotle’s explanation of the“unnatural”movement of bodies through space with one that closely approximates the modern theory of inertia, and demonstrated experimentally that freely falling bodies accelerate (fr. 73).

Most of our information about the detailed working of Strato’s system comes from Hero. Like Aristotle, Strato believed that one element can be“overpowered”and changed into its opposite, a process that can be observed in combustion, evaporation, condensation, and the absorption of water by earth. This occurs on a cosmic scale in the“exhalation”from the earth produced by subterranean heat, which gives rise to wind, rain, and most other meteorological phenomena. Another principle that played a major part in Strato’s meteorology was the“antiperistasis,”or“circular displacement”of heat and cold, which is explained by Seneca in a passage referring specifically to Strato (fr. 89):

Hot and cold always go in opposite directions and cannot be together; the cold gathers in places from which the hot has departed, and vice versa. . . . Wells and underground cavities are hot in winter when there is cold on the surface of the earth, because the hot has taken refuge there, yielding the upper regions to the cold to occupy; the hot for its part, when it has entered the lower regions and penetrated there as far as possible, becomes all the more powerful for being concentrated.

If such a concentration of heat is disturbed by an influx of cold, it will break out violently. This can happen in the earth, causing earthquakes, or in clouds, causing lightning, thunder, and typhoons. Probably Strato thought that the“exhalation”from the earth was produced by heat concentrated underground by“antiperistasis”when the surface of the earth cools at night. The direction of winds apparently was governed by horror vacui: when the“exhalation”disturbs the overlying air and produces pockets of high and low density, the operation of this law ensures that air flows into the low-pressure areas.

While many elements of Strato’s theory, including the“exhalation”and“antiperistasis,”had already appeared in the teaching of Aristotle and Theophrastus, Strato’s account is distinguished by being based on a limited number of principles, which–unlike some of those invoked by Aristotle–are natural laws in the modern sense. He succeeded in giving a unified explanation that was flexible enough to account for the phenomena in all their variety.

Strato seems to have devoted a good deal of attention to the nature of light and sound. Light, in his view, is a material emanation, which travels through the“pores”of air and other transparent substances and is reflected by any solid particles in its path, being modified by the colors of the surfaces from which it is reflected and probably also those of the media through which it passes. Transparency is a function of structure: bodies are transparent if they have continuous straight“pores”for light to pass through; provided this condition is satisfied, their density is immaterial. Strato’s explanation of sound is more interesting. He discovered that each sound is the result of many separate beats in a stationary medium (usually air), its pitch being governed by the frequency of the beats; thus he anticipated the true account in the most important respects. We do not know how he came to this conclusion: but he could have done so by reinterpreting, in the light of accurate observations of lyres and other sounding objects, Aristotle’s doctrine that sound is a“movement of alteration”traveling through a stationary medium from the object to the ear.

strato’s psychology is consistent with his cosmology. He denied the existence of an immaterial or immortal soul–he argued at considerable length against the doctrine of Plato’s Phaedo (frs. 118, 122–127)–or even of a transcendent element in the soul such as Aristotle’s“Active Reason"; he insisted, rather, that mental activity is not essentially different from any other kind of movement (fr. 74). The carrier of all psychic activity is the“breath” or “spirit” (πνєυ̑μα), which has its center in the brain behind the eyebrows and spreads to all parts of the body. The soul is a single entity. All mental processes, including sensation, take place at the center; the sense organs, which Strato described as“windows”of the soul, only receive and transmit stimuli; and when the act of perception is complete, the sensation is projected back to the organ where the stimulus originated in the same way as sounds are located at their points of origin (frs. 108–112). Sleep is due to the temporary withdrawal of the“spirit”from the extremities of the body to the psychic center; the complete withdrawal of the“spirit”results in death (frs. 128–129). Dreams are caused by residual movements in the“spirit”arising from past stimuli (frs. 130–131). As usual, most of the constituents of Strato’s doctrine have precedents in the Peripatetic school. The concept of the“Active Reason”had been questioned, but not definitely abandoned, by Theophrastus. The theory of“pneuma”had been originated by Aristotle and further developed by Theophrastus and by Diocles of Carystus, a famous physician and pupil of Aristotle. Only the location of the psychic center in the brain was entirely new; it came from Herophilus, the discoverer of the nervous system.

A noteworthy feature of Strato’s work was his extensive use of experiments. While not the first to perform them, he was the first to use experiments systematically to establish a fundamental cosmological doctrine. Strato’s experiments are not isolated, but form a progressive series in which each is based on the result of the previous one. Also characteristic of Strato are the care taken to define the conditions in which the experiment takes place and to eliminate all possible alternative explanations of the result, and the practice of pairing controlled experiments with observations of similar phenomena occurring under natural conditions. His purpose presumably was to avoid the charge that his experiments distorted nature.

That Strato’s system was in many ways a continuation of those of Aristotle and Theophrastus should not be allowed to obscure his very real originality. This lay in his ability to combine philosophical and scientific reasoning to produce a unified explanation of the world in which theories were shaped by observed facts and the facts themselves interpreted in the light of simple and consistent theories. The need for such a synthesis was particularly acute in the early third century b.c., a time when, largely as a result of Aristotle’s teaching and example, factual knowledge was increasing immensely and the natural sciences were asserting their independence. Nevertheless, Strato’s influence was limited. The centrifugal tendency among the sciences could not be arrested, and philosophical cosmology came to be dominated increasingly by religious considerations. Signs of a reaction against Strato in his own school appear in the last chapter of the pseudo-Aristotelian De spiritu, perhaps written within thirty years of his death. A few Peripatetics of the first century b.c. are reported to have held views similar to some of Strato’s; but it is not clear whether they were influenced by his writings, and it is very unlikely that they tried to revive his system as a whole. His name occurs rarely in the extant remains of philosophical writers belonging to other schools. The only pupils of Strato who made fruitful use of his ideas seem to have been the scientists of Alexandria, Ctesibius the engineer and Erasistratus the physician, and perhaps the astronomer Aristarchus of Samos.


I. Original Works. Editions of Strato’s works are F. Wehrli, Die Schule des Aristoteles, V (Basel, 1950; 2nd ed., 1969), which includes the named fragments and a selection of the others (references in this article are to this ed.); and H. B. Gottschalk,“Strato of Lampsacus: Some Texts,”in Proceedings of the Leeds Philosophical and Literary Society, Lit.-Hist. Sec., 11 , pt. 6 (1965), 95–182, which deals chiefly with the longer texts in which Strato’s name is not mentioned. Both eds. include a commentary and bibliography.

The best text of the De audihilibus is in I. Düring,“Porphyrius’ Kommentar zur Harmonielehre des Ptolemaios,”in Göteborgs högskolas årsskrift (1932), pt. 2, 67–77. The authorship of this work has been discussed by H. B. Gottschalk,“The De Audibilibus and Peripatetic Acoustics,”in Hermes, 96 (1968), 435–460.

II. Secondary Literature. See W. Capelle,“Straton 13,”in Pauly-Wissowa, Real-Encyclopädie der classischen altertumswissenschaft, 2nd ser., IVa (1931), 278–315; and M. Catzemeier, Die Naturphilosophie des Str. von L. (Meisenheim, 1970). The older literature has been superseded, but the following article is still worth reading: H. Diels,“Ueber das physikalische System des Straton,”in Sitzungsberichte der Preussischen Akademie der Wissenschaften zu Berlin, Phil.-hist. Kl. (1893), 101–127, also available in Kleine Schriften zur Geschichte der antiken Philosophie (Hildesheim, 1969), 239–265.



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