Democritus

Democritus (c.460 — c.370 BC) was an Ancient Greek pre-Socratic philosopher primarily remembered today for his formulation of an atomic theory of the universe. Many consider Democritus to be the “father of modern science”. None of his writings have survived; only fragments are known from his vast body of work.

The theory of Democritus held that everything is composed of “atoms”, which are physically, but not geometrically, indivisible; that between atoms, there lies empty space; that atoms are indestructible, and have always been and always will be in motion; that there is an infinite number of atoms and of kinds of atoms, which differ in shape and size.

The atomists agreed that motion required a void, but simply ignored the argument of Parmenides on the grounds that motion was an observable fact. Therefore, they asserted, there must be a void.

Democritus held that originally the universe was composed of nothing but tiny atoms churning in chaos, until they collided together to form larger units—including the earth and everything on it. He surmised that there are many worlds, some growing, some decaying; some with no sun or moon, some with several. He held that every world has a beginning and an end and that a world could be destroyed by collision with another world.

Empedocles

Empedocles (c. 490 – c. 430 BC) was a Greek pre-Socratic philosopher.

Empedocles established four ultimate elements which make all the structures in the world—fire, air, water, earth— in other words, the several states of matter are represented, being energies, gasses, liquids, and solids. Empedocles called these four elements “roots“. According to the different proportions in which these four indestructible and unchangeable elements are combined with each other the difference of the structure is produced.

The four elements are both eternally brought into union and parted from one another by two divine powers, Love and Strife. Love is responsible for the attraction of different forms of matter, and Strife is the cause of their separation.

If the four elements make up the universe, then Love and Strife explain their variation and harmony. Love and Strife are attractive and repulsive forces, respectively, which are plainly observable in human behavior, but also pervade the universe.

Like Pythagoras, Empedocles believed in the transmigration of the soul, that souls can be reincarnated between humans, animals and even plants. Empedocles was a vegetarian and advocated vegetarianism, since the bodies of animals are the dwelling places of punished souls.

Parmenides of Elea

Parmenides of Elea (c. 515 – 450 BC) was a pre-Socratic Greek philosopher from Elea. He was the founder of the Eleatic school of philosophy.

For him and his pupils, the phenomena of movement and change are simply appearances of a changeless, eternal reality. This interpretation could settle because of various wrong translations of the fragments.

Reality is one ‘thing’ (Monism) It never moves or changes. It has and will remain the same for eternity.

Reality is one ‘thing’ (Monism) It never moves or changes. It has and will remain the same for eternity. “It needs must be that what can be thought and spoken of is; for it is possible for it to be, and it is not possible for, what is nothing to be. ” It is impossible to form a concept of “nothingness” or non being.

Heraclitus of Ephesus

Heraclitus of Ephesus (c. 535 – c. 475 BC) was a pre-Socratic Greek philosopher. Little is known about his early life and education, but he regarded himself as self-taught and a pioneer of wisdom.

Ever-newer waters flow on those who step into the same rivers. Everything changes and nothing remains still … and … you cannot step twice into the same stream. 

Heraclitus considered fire as the most fundamental element. He believed fire gave rise to the other elements and thus to all things. He regarded the soul as being a mixture of fire and water, with fire being the noble part of the soul, and water the ignoble part. A soul should therefore aim toward becoming more full of fire and less full of water: a “dry” soul was best. According to Heraclitus, worldly pleasures made the soul “moist”, and he considered mastering one’s worldly desires to be a noble pursuit which purified the soul’s fire.

Pythagoras of Samos

Pythagoras of Samos (c. 570 – c. 495 BC) was an Ionian Greek philosopher and the eponymous founder of the Pythagoreanism movement. His political and religious teachings influenced the philosophies of Plato, Aristotle, and, through them, Western philosophy.

It was said that he was the first man to call himself a philosopher (“lover of wisdom”)

One of the best known mathematical formulas is Pythagorean Theorem, which provides us with the relationship between the sides in a right triangle. It states that the square of the hypotenuse (the side opposite the right angle) is equal to the sum of the squares of the other two sides.

His teaching most securely identified with Pythagoras is metempsychosis, or the “transmigration of souls”, which holds that every soul is immortal and, upon death, enters into a new body. Pythagoras may have claimed to possess the ability to recall his former incarnations.

Another belief attributed to Pythagoras was that of the “harmony of the spheres”, which maintained that the planets and stars move according to mathematical equations, which correspond to musical notes and thus produce an inaudible symphony. The Pythagoreans believed that music was a purification for the soul, just as medicine was a purification for the body.

Thales of Miletus

Thales of Miletus (c. 624 – c. 546 BC) was a pre-Socratic Greek philosopher, mathematician, and astronomer from Miletus.

Thales is recognized for breaking from the use of mythology to explain the world and the universe, and instead explaining natural objects and phenomena by theories and hypotheses, in a precursor to modern science.

Thales predicted the solar eclipse of May 28, 585 BC. It is not known how Thales was able to predict the Eclipse,but it is known that Thales of Miletus was one of the famous “Seven Sages of Greece.”

Thales found the height of pyramids by comparison between the lengths of the shadows cast by a person and by the pyramids.

Thales aimed to explain natural phenomena via rational hypotheses that referenced natural processes themselves. For example, rather than assuming that earthquakes were the result of supernatural whims Thales explained them by hypothesizing that the Earth floats on water and that earthquakes occur when the Earth is rocked by waves.

Thales thought all things are full of gods. Aristotle posits the origin of Thales thought on matter generally containing souls, to Thales thinking initially on the fact of, because magnets move iron, the presence of movement of matter indicated this matter contained life.

Thales’ hypothesis about the nature of all matter – that the originating principle of nature was a single material substance: water.

Thales’ hypothesis about the nature of all matter – that the originating principle of nature was a single material substance: water. Thales thought the Earth must be a flat disk which is floating in an expanse of water.