Summary

Democritus of Abdera (Abdera, Thrace, c. 460 B.C.-c. 370 B.C.) Greek disciple of Leucippus, founder of atomism and teacher of Protagoras who lived between the 5th-4th centuries B.C. He belonged to the School of Abdera and had a wide field of interests, but is especially remembered for his atomistic conception of a universe composed only of atoms and vacuum. He has been considered "the father of physics" or "the father of modern science".

The exact contributions of Democritus are difficult to separate from those of his mentor Leucippus, since they are often mentioned together in the texts of the doxographers. One of their differences lies in his skepticism, which he said: "Nothing we know for certain, for the truth is in the deep. He said: "We know nothing for certain, for the truth is in the deep." Democritus also explained sensations in a mechanistic way, defended a hedonistic ethics and a cosmopolitan democratic politics.

Traditionally he is considered a pre-Socratic philosopher, although this is an error of chronology, since he was a contemporary of Socrates. From a philosophical point of view he is associated with the pre-Socratics because of his subject matter (physis), whereas Socrates and the philosophers who followed him dealt with ethical-political themes. He was largely ignored in ancient Athens, but was known and quoted by Aristotle. Plato was also familiar with the atomism of Democritus, which he disliked so much that he wished to burn all his books. Nevertheless, the doctrines were very influential in Epicureanism, and revived in the modern age during the Enlightenment.

Democritus was also known as The Laughing Philosopher (in contrast to Heraclitus, "the weeping philosopher") as he was prone to laugh at the ignorance of the world and considered joy as the goal of life.

His name, Δημόκριτος, Dēmokritos, meaning "chosen of the people," was known by the nickname Milesius or Abderite. He was born in the LXXX Olympiad (460-457 BC) according to Apollodorus of Athens and in the LXXVII Olympiad (470 BC. ) according to Thrasyllus, in the city of Abdera (Thrace), capital of a Greek polis located on the current north coast of Greece, east of the mouth of the river Nestos, near the island of Thasos, although it is also said that he was from the Ionian colony of Miletus, belonging to Theos. His father Hegesistratus or Athenocritus belonged to a noble family. Democritus was a disciple of Leucippus, probably also a native of Abdera, and perhaps Anaxagoras, being forty years older than he. Anaxarchus and Protagoras were also natives of Abdera.

He studied with Chaldean magicians and scholars that King Xerxes I of Persia left in his father's house, when he stayed at his father's home during his military campaign against the Greeks in the medical wars, and while still very young, he learned from them mainly astrology and theology. While still very young, he learned from them especially astrology and theology. His father divided his inheritance to his sons, being Democritus the youngest of his three brothers, corresponding to him a hundred talents that he spent in numerous trips to distant countries, to satisfy his thirst for knowledge, in which he would have learned from Persian magicians, Egyptian and Chaldean priests. It is said that he traveled through Egypt, where he lived for five years and acquired knowledge of geometry, as well as visited Ethiopia, Mesopotamia, Babylon, Chaldea and Persia and even reached India in search of the knowledge of the gymnosophists. Theophrastus also spoke of him as a man who had seen many countries. Clement of Alexandria puts the following quote from the philosopher: "I have seen, he says in the passage alluded to, most of the climates and nations. I have heard the wisest men, and no one has surpassed me in demonstrating the composition of lines, not even the Egyptians, who call themselves arpedonaptas, among whom I have resided for eight years.

He traveled throughout Greece to acquire a better knowledge of their cultures. He mentions many Greek philosophers in his writings, and his wealth enabled him to purchase their writings. Leucippus, the founder of atomism, was the greatest influence on him. He also praises Anaxagoras and was a friend of Hippocrates. Upon his return, he lived poorly and was supported by his brother Damascus.

In Athens he was widely ignored despite having won five philosophical contests. Nevertheless, Democritus' work was widely known. Aristotle himself quoted it in his Metaphysics and other works. Of him he said that "he seems not only to have thought carefully about all problems, but to have distinguished himself from the rest." The reason he did not acquire fame was that he himself "did not take care to be known; and although he knew Socrates, Socrates did not know him. He also attended to listen to the Pythagoreans. It is a famous anecdote that Plato detested Democritus so much that he wanted all his books to be burned but was prevented by the Pythagoreans Amiclas and Clitias on the grounds that it was useless since his writings were circulated in many places. Plato criticized his cosmological theories in his dialogue Timaeus, but never explicitly cited his name.

Democritus was known in his time for his extravagant character. It is said of him that he foresaw the future and numerous legends were attributed to him. One of them says that he plucked out his eyes in a garden so that the contemplation of the external world would not interfere with his meditations.

Protagoras was his direct disciple and so was Nausiphanes, who was in turn Epicurus' teacher.

Hipparchus of Nicaea assures us, according to Diogenes Laertius, that Democritus died painlessly at the age of one hundred and nine years. All ancient authors who have referred to his age agree that he lived about one hundred years. According to Aulus Gallio, Tertullian and Cicero, Democritus voluntarily deprived himself of life. There are two dates for his death: in 420 B.C., or, the one currently taken as true, in 370 B.C.

Diogenes Laertius listed a series of writings of Democritus exceeding seventy works on ethics, physics, mathematics and even technical arts music, so Democritus is considered an encyclopedic author. Thrasyllus compiled Democritus' works into tetralogies, under the titles "ethics" (eight works), "works on nature" (sixteen works), "mathematics" (twelve works), "literary criticism and arts "(eight works), and "technical" works (eight works, including several on medicine). This compilation he called The Pentathlete.

Among his most important works is his Great Diacosmos, for which he obtained, by popular plebiscite, a prize of five hundred talents. He wrote precisely the Great Diacosmos to defend himself against the possible accusations made against those who squandered the inheritance of his parents. He also wrote another work when he was young called Little Diacosmos. This title is also attributed to his teacher Leucippus.

No such writings were preserved, and of all this production only about three hundred minor fragments have survived, most of which are moral reflections of which only fragments are known, mainly thanks to the allusions of Aristotle and Theophrastus. Diogenes Laertius collected both the doctrines of Democritus and his teacher. Democritus preserved about eighty-four moral maxims of Democritus. There are several collections of these fragments, such as those of Diels-Kranz, and Walter Leszl.

Despite being a contemporary of Socrates, Aristotle brought Democritus together with the pre-Socratic natural (physical) philosophers. Among the thinkers who influenced Democritus' doctrines, the Egyptian geometricians and Anaxagoras, whose homeomorphies are considered the most immediate antecedent of the theory of atoms, are worth mentioning.

Along with his teacher, Leucippus, Democritus is considered the founder of the atomist school. He belongs to the post-eleatae, insofar as he accepts the principles established by Xenophanes and Parmenides, but develops a pluralistic philosophy like Anaxagoras or Empedocles. For Democritus, the principles of all things are atoms and the void, the rest is doubtful and opinionated. For example, the reason why Democritus thinks he has a pen in his hand is a purely physical and mechanistic process; thought and sensation are attributes of matter gathered in a sufficiently fine and complex way, and not of any spirit infused by the gods into matter.

He detested pleasures that in the long run produce pain. He presented matter as self-created, and composed of atoms. Physical and chemical changes were due to physics, not magic. Although Democritus' materialistic atomism has been identified as an atheistic doctrine in later times, it is not clear whether he denied entirely that gods could exist.

Atomism

Democritus developed the "atomic theory of the universe", conceived by his mentor, the philosopher Leucippus. Leucippus and Democritus thought differently from the Eleates, because while the Eleates did not accept motion as a reality, but as a phenomenon, the atomists assume that motion exists in itself. Democritus spoke for the first time of the force of inertia. According to Aristotle, the arguments of Democritus are derived from the knowledge of Nature rather than from "dialectics" (logic). The atomist theory of Democritus and Leucippus can be schematized as follows:

τομο (tomo)=división, «indivisible», o «sin división».​

Democritus' theory postulates that all bodies are composed of these corpuscles that are physically indivisible and "infinite in number", which are distinguished in shape, size, order, position and weight, the "greater the indivisible, the more it weighs". This raises the problem of whether atoms can be divided or have parts, as evidenced by their variations in shape. David Furley suggested that the atomists distinguished between the physical and theoretical indivisibility of atoms. For the atomist Epicurus, atoms have conceptually and physically indivisible minimal parts. The question of whether atoms originally possessed weight for the atomists is still debated. Aetius said that Democritus did not assign weight to atoms, which Epicurus added in order to explain the motion of atoms. According to Eduard Zeller, atoms are continuously falling according to their weight. For Bertrant Russell, it is most likely that "they were moving randomly as in the modern kinetic theory of gases". Balme warns to suppose that for the atomists the atomic motion is inertial. Other scholars suppose that the weight was the result of the centripetal forces of a cosmic whirlpool (dine) that the atoms form by necessity.

Atoms are in eternal motion. The motion of atoms is an inherent feature of them, a fact irreducible to their existence, infinite, eternal and indestructible. From these figures they "derive alteration and generation, namely, generation and corruption by their association and dissociation, and alteration by the order and position which they assume." And since they "believed that truth is in observable phenomena" and that "because of the changes affecting the compound, the same thing takes on contrary appearances to different observers," in the same way that a tragedy and a comedy are composed with the same letters. Aristotle explains that, for Democritus, the differences between atoms cause by their figure, order, and position the differences between things in "structure," "contact," and "direction." "Thus A and N differ by figure, the sets AN and NA by order, and Z and N by position."

The atomistic vacuum hypothesis was a response to the paradoxes of Parmenides and Zeno, the founders of metaphysical logic, who presented difficult-to-answer arguments in favor of the idea that there can be no motion. The Eleates argued that any motion would require a void, which is nothing, but nothingness cannot exist. Parmenides' position was, "It is said that there is a void; therefore, the void is not a nothing; therefore, it is not the void." Similarly, Melysius of Samos asserted that "Everything is immobile" because if anything were moving there would have to be a void, "but the void is not to be found among existing things."

The atomists agreed that motion required a vacuum, but they simply ignored Parmenides' argument on the grounds that motion was an observable fact. They asserted that bodies can only move in an empty place, "since it is impossible for the full to receive anything". For Democritus the void exists between the atoms as a non-being that allows the plurality of differentiated particles and the space in which they move. Aristotle already says that the "void is rather an extension in which there is no sensible body and, since they believe that every entity is corporeal, they affirm that the void is that in which there is nothing".

The form that each atom possesses makes it possible for them to assemble - although they never fuse (there is always a minimum amount of vacuum between them that allows their differentiation) - and form bodies, which will separate again, the atoms remaining free again until they join with others. The atoms of a body separate when they collide with another set of atoms; the atoms that remain free collide with others and assemble or continue moving until they find another body.

The atoms form by necessity a vortex or whirlpool (dine) and their collisions, unions and separations form the different elements (fire, water, air and earth), beings and reality in all its diversity. Every object and every event that occurs in the universe, would be the result of collisions or reactions between atoms. Therefore, there is no initial cause nor a purpose in the movement. Although it is attributed to his master that.

Nothing comes from chance, but from reason and necessity.

Democritus is quoted as saying that.

Everything that exists in the universe is the fruit of chance and necessity.

However, it is most likely that the term "chance" was understood as "absence of purpose". Aristotle says that "Democritus, by not dealing with the final cause, attributes to necessity everything that nature does". Nature is explained in a mechanistic way. The atomistic model is a clear example of a materialistic model, since chance and chain reactions are the only ways to interpret it. Democritus was in favor of a fatalistic determinism, which denied chance, attributing it to necessity and a product of the imagination of men, not being able to explain the causal relationships between phenomena. Epicurus, on the other hand, emphasized chance as the absence of necessity with atomic "turning" (parenklisis).

Men have forged the image of chance to justify their own thoughtlessness. It is rare, indeed, that chance is opposed to wisdom; on the contrary, most of the time in life, the penetration of an intelligent man can direct all things.

Democritus said that there was neither above nor below in the infinite void. Because all are atoms and there is an infinite quantity of atoms, the stars like the Sun and the Moon are spinning moles of atoms and there are infinite worlds, subject to generation and corruption. For Democritus, the Sun was a body of great size. According to Anaxagoras and Democritus, the Milky Way is the light of certain stars and that due to the rays of the Sun passing through the Earth it is impossible to observe the stars. Democritus said that his ideas and those of Anaxagoras about the Sun and the Moon come from ancient opinions. Like the other atomists, Democritus believed in a flat Earth and challenged the arguments in favor of its sphericity.

Anthropology

His work on nature is known through quotations. He spent much of his life experimenting and examining plants and minerals, and wrote extensively on many scientific subjects. Among them: Of Nature, Of the Flesh (two books), Of the Mind and Of the Senses (some joined in Of the Soul), Of Humors and Of Colors.

For both Democritus and Leucippus, the human soul, like the world, is composed of atoms. Aristotle attributes to Democritus a comparison of the movement of the atoms of the soul with the dust motes of the sun, which dance in all directions. Its atoms are spherical, like fire, and in every living being there is fire, mainly in the brain or in the chest. The loss of a quantity of small particles of the spirit produces sleep, and excessive abandonment is the cause of death. The mind of man would be formed by light, soft, refined spherical atoms, and the body, by heavier atoms. Sensible perceptions, such as hearing or vision, are explicable by the interaction between the atoms of the effluvia that depart from the perceived thing and the atoms of the receiver. The latter justifies the relativity of sensations.

Thought, consciousness and sensation are the result of the aggregation or diverse combination of the atoms that constitute the substance of the soul. Democritus held that the gods were superior beings but mortal and subject to fate (fatum), that is, to the immutable law of the motion of atoms. According to Diogenes Laertius, who quotes Favorinus, Democritus ridiculed the claims of Anaxagoras about the Nous.

For many philosophers, including Democritus, an arithmetic-geometric principle prevailed to explain many facts. Thus, Democritus explained even the taste of things under this aspect. He attributed a special geometrical form to substances to give them this or that "taste": the sweet sensation was due to the spherical form of the substance that forms the body that produces it; the bitter was due to the smooth and rounded form, and the sour or acid to the angular and sharp. An analogous origin and interpretation was attributed to the phenomena of touch.

After having said "by convention the color, by convention the sweet, by convention the salty, but in reality there are only atoms and emptiness."

These sensory properties exist not "by nature", but "conditionally". This conception of the senses is taken up in John Locke's distinction of objective "primary qualities" (such as size or weight) and subjective "secondary qualities" (such as taste or color) of things.

Using rational science he tried to seek an explanation of all natural phenomena starting from a small number of basic principles. He was also concerned with the corpuscular nature of light. Empedocles spoke of "effluvia" that emanate from objects and are perceived by the eyes. In contrast to Empedocles' theory of emission, Democritus supported the theory of reception, according to which vision is caused by the reception of rays of light that are received by the eyes and make it possible to recognize objects. Democritus gave a mechanistic explanation of sensations with his atomistic doctrines. He exchanged the effluvia for atoms that through the senses collide with the soul, also composed of atoms, "which generate the appearances, what we perceive, the superficial" depending on the form and texture of the atoms. Democritus and Epicurus designate the "representations" "sent" by things to our senses as "images" ("idols").

"Democritus says that, by nature, nothing has color, for the elements, in fact, lack qualities, both the solids and the void. The compounds of these acquire color through arrangement, structure, and impulse, which are order, figure, and position. Apart from these, there are only representations. The difference of colors offered by the representations are four: white, black, red and green."

Following Empedocles, he considered four colors as fundamental: white, black, red and yellow.

Epistemology

Generally, a proposal, before acquiring the status of a law, starts from a mere empirical generalization that aspires to reach a crucial requirement: to be explained. Once this is done, inductive statistics concretizes its idea. Its premises cease to harbor the possibility that the conclusion is not fulfilled, and thus the law is constituted. In the case of Democritus the development was reversed. Democritus began by offering an explanation to a parcel of reality that he had no opportunity to observe, nor, consequently, to falsify or verify if it had been fulfilled. Verificationism could not be an essential requirement to give credibility to his explanation and establish it as a law, and Democritus was aware of this:

The true and deep knowledge is that of the atoms and the void, because they are the ones that generate the appearances, what we perceive, the superficial.

For Democritus there are two kinds of knowledge, the one he calls "legitimate" (γνησίη, gnēsiē , "genuine") and the other "bastard" (σκοτίη, skotiē , "obscure").

But in the Canons Democritus says that there are two kinds of knowledge, one through the senses and the other through the intellect. Of these he calls "legitimate," through the intellect, which attests its reliability for the judgment of truth, and through the senses, he calls "bastard," denying its infallibility in discriminating what is true. To quote his actual words: Of knowledge there are two forms, one legitimate and the other bastard. To the bastard belongs all of this group: sight, hearing, smell, taste, touch. The other is legitimate and separate from that. Then, preferring the legitimate to the bastard, he continues: When the bastard can no longer see anything smaller, nor hear, nor smell, nor taste, nor perceive by touch, but the finer things must be examined, then comes the legitimate, since he has a finer organ of perception.

The finest knowledge is that of reason, which leads to the discovery of the essence of the world: the atoms and the void. The deductions of Democritus and the other philosophers were made from logic, rational thought, relegated the relevance of empiricism to the background, and placed little faith in sensory experience, i.e. that which was appreciated by the senses. He explained sensible perceptions such as hearing or vision, with the interaction between atoms emanating from the perceived object to the receiving organisms. The latter is what strongly proves the relativity of sensations. Very fine substances ("idols") are given off by the objects and act on the sense organs, but only provide "obscure" knowledge. Nevertheless:

the senses, addressing reason, speak thus: "O wretched reason, you who take your certainties from us! Do you seek to destroy us? Our fall, no doubt, will be your own destruction."

Democritus raises the problem of the correlation between the senses and reason in knowledge. Knowledge of atoms starts from sensory experience, but the senses themselves have no direct access to the external world. In the above fragment, Democritus seems to respond skeptically by accusing the mind of overthrowing the senses, although that is its only access to truth. In other passages they speak of a gap between what we can perceive and what actually exists (see: Qualia, Explanatory gap and Difficult problem of consciousness).

In reality we know nothing about anything, but that in all men their opinion is a reformation (of their disposition).

Knowledge is based on the analogy of things in the visible world. In contrast, his disciple Protagoras held that all sensations are just as true as any other. Epicurus also believed that the perceptions produced by atoms are true and represent the physical world as it is, thus being the basis of knowledge and morality.

Ethics

Democritus' ethics and politics come to us mainly in the form of maxims, which can be linked, directly or indirectly, to his physics. The Stanford Encyclopedia of Philosophy has gone so far as to say that "despite the large number of ethical sayings, it is difficult to construct a coherent account of Democritus' ethical views", noting that there is a "difficulty in deciding which fragments are authentically Democritus'". According to Laertius, the aim of his ethics is to achieve tranquility of mind (ataraxia), not through delights but due to the absence of fear or any other passion. Democritus advocated sanity and moral self-esteem. Both happiness and unhappiness are found in the soul: in line with the postulates of the Greek Enlightenment, Democritus equates human happiness with euthymia or joy produced by thought. Good and truth are identical, but what is pleasant is not so by the senses. These doctrines contain elements that will be developed by Epicurean ethics. In addition, there is a lost treatise of his on happiness that was used by Seneca and Plutarch.

Justice consists in doing what is due and injustice in not doing it or doing it badly. The best thing is to prevent an injustice, the worst thing is to be an accomplice, because one is more unhappy than suffering it, similar to moralsocratic intellectualism. Democritus had favorable opinions about friendship versus family. He also expressed comments about the superiority of man over woman.

Like Epicurus, he claimed that out of ignorance and fear of death, people imagine misleading fables about the afterlife.Democritus and Leucippus rejected arbitrary supernatural explanations of phenomena and replaced them with natural deterministic laws that govern all phenomena through the behavior of atoms, including human beings and their actions. In denying freedom, Democritus was aware of the negative implications for moral responsibility. In this respect, Democritus seems to anticipate the idea of semi-compatibilism of determinism and moral responsibility.

It is not he who commits injustice who is abhorrent, but he who does it deliberately.

A couple of centuries later, the atomist Epicurus added an element of chance to break the causal chain and provide even more control and moral responsibility. However, for Monte Ransome Johnson "there is a risk of anachronism in interpreting and evaluating Democritus as a philosopher through the highly problematic categories of free will and determinism." Democritus grappled with the problem of the causes of goodness and success, in which training, thought, and education play the most important role. His focus on intellectual powers as the source of agency and the cause of success led him to important advances in moral psychology.

Policy

Democritus emphasized the importance of the state and political life. Democritus said that "equality is everywhere noble," but he did not embrace enough to include women or slaves in this sentiment. In his History of Western Philosophy, Bertrand Russell writes that Democritus was enamored of "what the Greeks called democracy. Poverty in a democracy is better than the prosperity of tyrants, for the same reason that one prefers freedom to slavery. Nevertheless, the command belongs to the wisest by nature. Democritus said that "the wise man belongs to all countries, because the home of a great soul is the whole world". The city must also be in harmony, even in war. He was also in favor of capital punishment for the unjust and criminals.

Democritus thought that the first humans lived a wild and disorderly life, feeding on herbs and fruit that grew on trees. They then grouped into societies out of fear of wild animals. He believed that these early people had no language, but that they gradually began to articulate their expressions, establishing symbols for each type of object, and thus came to understand each other.

He says that early men lived laboriously, without any of the utilities of life; clothing, houses, fire, domestication and agriculture were unknown to them. Democritus presents the early period of mankind as one of learning by trial and error, and says that each step led slowly to further discoveries; they sheltered in caves in winter, stored fruits that could be preserved.

Aesthetics

Later Greek historians consider that Democritus established aesthetics as a subject of research and study, since he wrote theoretically about poetry and fine arts long before authors such as Aristotle, but only fragments of such works exist, and his empirical and materialistic attitude is manifested by the fact that he focused more on the theory of art than on beauty. His empirical and materialistic attitude is manifested by the fact that his focus was more on the theory of art than on beauty. The arts are the work of the natural forces of man, without divine inspirations, whose model is nature and whose aim is pleasure.

Neither art nor wisdom are accessible to those who have learned nothing.

Democritus held the theory of the evolution of culture and that the arts were born of man's natural ability to imitate nature, the purpose of art being pleasure. These positions were novel for the time, departing from the archaic opinions held by the poets, from the mathematical Pythagorean mysticism and the minimalism of the sophists.

He is best known for his atomic theory but he was also an excellent geometrician, a science he taught to his disciples. He acquired his mathematical knowledge during his travels and from the Pythagoreans. It is said that his achievements in mathematics were such that even the "string-tensioners" in Egypt managed to surpass him. His physical atomism forms an infinitesimal approach.

He wrote numerous works, but only a few fragments survive, as well as several treatises on geometry and astronomy, which have been lost. It is believed that he also wrote on number theory. According to Archimedes, he found the formula that expresses the volume of a pyramid. He also proved that this formula can be applied to calculate the volume of a cone. Two theorems are attributed to him.

Furthermore, Plutarch stated that Democritus had posed the following question: if a plane parallel to the base cuts a cone, are the surfaces of the section and the base of the cone equal or unequal? If they are equal, the cone becomes a cylinder, while if they are unequal, the cone becomes an "irregular cone" with indentations or steps. This question could easily be solved by calculus, and it has therefore been suggested that Democritus can be considered a precursor of infinitesimals and integral calculus.

Because of his mechanism, Democritus was one of the most reviled scholars of antiquity: his philosophy of atomism launched a fundamental challenge to the teleological conception of the world outlined by Anaxagoras, developed by Plato in the Timaeus and Book X of the Laws. In the short run, this philosophy met with determined opposition from Plato, but also from Aristotle and his successors. Aristotle holds a natural teleology governed by form.

In Roman times, atomism met with opposition from the Stoics. Later in the 6th century, the atomist tradition came into conflict with the interests of the Christians, who condemned it. La Fontaine mocked the atomist doctrine of Democritus.

Nevertheless, Democritus was admired by the great philosophers. Diogenes Laertius composed some verses in his honor. Cicero said of him: "There is nothing he does not occupy himself with". Seneca considered him "the most subtle of all the Elders". Aristotle, Theophrastus, Tertullian, Epicurus, Metrodorus have devoted entire treatises to discuss his system.

Epicurus, a later philosopher who took up this theory, modified the philosophy of Democritus by not accepting the determinism that atomism entailed in its original form. He therefore introduced an element of chance into the motion of atoms, a deviation (clinamen) from the chain of causes and effects, thus ensuring freedom. Since, in Democritus' view, the cosmos is not determined by a power that was above it, this way of thinking can be found widespread since the Renaissance and permeates all modern philosophy and science, from Giordano Bruno, Galileo Galilei and Spinoza. Epicurus and his later follower, Lucretius, exerted great influence on the development of materialism in modern times, during the seventeenth and eighteenth centuries.

The idea of the atomic vacuum survived in a refined version as Newton's theory of absolute space, which fulfilled the logical requirements of attributing reality to non-being. Einstein's theory of relativity provided a new answer to Parmenides and Zeno, with the idea that space itself is relative and cannot be separated from time as part of a generally curved space-time manifold. Consequently, Newton's refinement is now considered superfluous.

German philosopher Karl Marx's doctoral dissertation, "Difference between Democritus' and Epicurus' Philosophy of Nature," was a Hegelian dialectical analysis of the differences between the natural philosophies of Democritus and Epicurus. Marx saw Democritus as a rationalist skeptic whose epistemology was inherently contradictory.

According to Bertrand Russell, the viewpoint of Leucippus and Democritus "bears a remarkable resemblance to that of modern science, and avoided many of the errors to which Greek speculation was prone" and "is the last of the philosophers free from the taint that poisoned all later ancient and medieval thought."

Karl R. Popper admired rationalism, humanism, love of freedom and wrote that Democritus, together with his compatriot Protagoras, "formulated the doctrine that the human institutions of language, custom and law are not taboo but man-made. Not natural but conventional, insisting, at the same time, that we are responsible for them."

Jorge Luis Borges used his figure to express a dilemmatic or bicornute syllogism with the liar's paradox. In this one, Democritus swears that the Abderitans are liars, being himself an Abderitan.

The laughing philosopher

There are anecdotes according to which Democritus often laughed ironically at the progress of the world, and said that "laughter makes wise", which led him to be known, during the Renaissance, as "the philosopher who laughs" or "the laughing abderite", opposing him to Heraclitus, "the philosopher who cries". Democritus considered good spirits as the object of life, and he once affirmed that:

"Life without joys is a long road without shelters."

Hence the reference in Horace's epistles, Si foret in terris, rideret Democritus ("If he were on earth, Democritus would laugh).

Sources

1. Democritus
2. Demócrito