Physics In his letter to Herodotus (not
the historian), Epicurus presented three principles as to the nature of the physical world: that which exists cannot come into being from that which does not exist; that which is destroyed does not cease to exist; and all that exists now always did exist and always will. The object of these principles was to establish the fact that all that constitutes the world is permanent and unchanging. Epicurean physics held that the entire universe consisted of two things: matter and void. Matter is made up of atoms, which are tiny bodies that have only the unchanging qualities of shape, size, and weight. The Epicureans believed that atoms were unchanging because the world was ordered and that changes had to have specific and consistent sources, e.g. a plant species only grows from a seed of the same species, but that in order for the universe to persist, what it is ultimately made up of must not be able to be changed or else the universe would be essentially destroyed. Because of the infinite supply of atoms, there are an infinite number of worlds, or
cosmoi. because void is necessary for matter to move. Anything that consists of both void and matter can be broken down, while if something contains no void, then it has no way to break apart because no part of the substance could be broken down into a smaller subsection of the substance. Atoms are constantly moving in one of four different ways. Atoms can simply collide with each other and then bounce off of each other. This downwards motion is natural for atoms; however, as their fourth means of motion, atoms can at times randomly swerve out of their usual downwards path. If it were not for the swerve, humans would be subject to a never-ending chain of cause and effect.
Sense perception Epicureans believed that the senses also relied on atoms. Every object was continually emitting particles from itself that would then interact with the observer. All sensations, such as sight, smell, or sound, relied on these particles. and that errors arise in how we judge those perceptions. For example, if someone sees a tower from far away that appears to be round, and upon approaching the tower they see that it is actually square, they would come to realize that their original judgement was wrong and correct their wrong opinion.
Criterion of truth Epicurus is said to have proposed three
criteria of truth: sensations (
aisthêsis), preconceptions (
prolepsis), and feelings (
pathê). A fourth criterion called "presentational applications of the mind" (
phantastikai epibolai tês dianoias) was said to have been added by later Epicureans. These criteria formed the method through which Epicureans thought we gained knowledge. The observer makes the error in assuming that the image he or she receives correctly represents the oar and has not been distorted in some way. This acted as a justification for one's judgements about the thing being perceived. An individual's preconceptions are his or her concepts of what things are, e.g. what someone's idea of a horse is, and these concepts are formed in a person's mind through sensory input over time. When the word that relates to the preconception is used, these preconceptions are summoned up by the mind into the person's thoughts. It is through our preconceptions that we are able to make judgements about the things that we perceive. We receive impressions of such things directly in our minds, instead of perceiving them through other senses. Unlike other schools which considered virtue the supreme good such as
Stoicism, he considered the virtues to be an instrumental but essential good to living a pleasant life, all stemming from practical wisdom on how to live pleasantly. Hence, Epicurus advocated living in such a way as to derive the greatest amount of pleasure possible during one's lifetime, yet doing so moderately in order to avoid the suffering incurred by indulgence in pleasures that could cause pain. He also considered the study of the natural world necessary to dispel fears about mythology. The Epicurean views on marriage and having children are disputed with some considering him strongly anti-marriage and anti-family unless circumstances forced one to and others thinking he only warned against imprudent marriage and child-rearing when circumstances made it unwise. Additionally, he viewed recreational sex as a natural, but not necessary, desire that never benefited a man, since it didn't relieve any pain, and one must be content with it not harming him. Since the political life could give rise to desires that could disturb virtue and one's peace of mind, such as a lust for power or a desire for fame, participation in politics was discouraged. Further, Epicurus sought to eliminate the fear of the gods and
of death, seeing those two fears as chief causes of strife in life.
Pleasure Epicureans had a very specific understanding of what the greatest pleasure was, and the focus of their ethics was on the avoidance of pain rather than seeking out pleasure, arguing that pleasure reaches its maximum in the removal of all sources of pain, either mental or bodily. Epicureanism divided pleasure into two broad categories:
pleasures of the body and
pleasures of the mind.
Pleasures of the body involve sensations of the body, such as the act of eating delicious food or of being in a state of comfort free from pain, and exist only in the present.
Pleasures of the mind involve mental processes and states; feelings of joy, the lack of fear, and pleasant memories are all examples of pleasures of the mind. The Epicureans further divided each of these types of pleasures into two categories:
kinetic pleasure and
katastematic pleasure. Absence of pain,
aponia, and lack of disturbance of mind,
ataraxia, are two of the katastematic pleasures and often seen as the focal ones to
Epicurus.
Kinetic pleasure is the physical or mental pleasures that involve action or change. Eating delicious food, as well as fulfilling desires and removing pain, which is itself considered a pleasurable act, are all examples of kinetic pleasure in the physical sense. According to Epicurus, feelings of joy would be an example of mental kinetic pleasure. The ultimate goal then of Epicurean ethics was to reach a state of
aponia and
ataraxia. •
Natural and necessary: These desires are limited desires that are present in all humans and contribute to our happiness; it is part of human nature to need them since we experience pain without them. They are necessary for one of three reasons: necessary for happiness, necessary for freedom from bodily discomfort, and necessary for life. Friendship and knowledge of natural science (to dispel mythology) would belong to the first category of desires, where as food and drink, clothes, medicine, and shelter belong to the second and third categories. These desires are the most important to fulfill. In other words they do not need to be fulfilled for happiness, freedom from bodily discomfort, or for life. Wanting to eat delicious food and drink, sex, and a nice home are examples of natural but not necessary desires. They are considered fine to fulfill so long as they do not cause harm and certainly not at the cost of our natural and necessary desires. Unnecessary desires were to be treated with caution so as to not cause pain but fine to fulfill if they did not, and unnatural and unnecessary desires were to be eliminated.
Politics The Epicurean understanding of
justice was inherently self-interested. Justice was deemed good because it was seen as mutually beneficial pact to neither harm nor be harmed. Individuals would not act unjustly even if the act was initially unnoticed because of possibly being caught and punished. Both punishment and fear of punishment would cause a person disturbance and prevent them from being happy. The social contract theory established by Epicureanism is based on mutual agreement, not divine decree. To Epicureans all our social relations are a matter of how we perceive each other, of customs and traditions. No one is inherently of higher value or meant to dominate another. However, Epicureanism is adaptable to circumstance, as is the Epicurean approach to politics. Epicurus rejected any possibility of an afterlife, while still contending that one need not fear death: "Death is nothing to us; for that which is dissolved, is without sensation, and that which lacks sensation is nothing to us." From this doctrine arose the Epicurean Epitaph:
Non fui, fui, non sum, non curo ("I was not; I was; I am not; I do not care."), which is inscribed on the gravestones of his followers and seen on many ancient gravestones of the
Roman Empire.
Gods Epicureanism does not deny the existence of the gods; rather, it denies their involvement in the world. According to Epicureanism, the gods do not interfere with human lives or the rest of the universe in any way – thus, it shuns the idea that frightening weather events are divine retribution. One of the fears the Epicurean ought to be freed from is fear relating to the actions of the gods. The manner in which the Epicurean gods exist is still disputed. Some scholars say that Epicureanism believes that the gods exist outside the mind as material objects (the
realist position), while others assert that the gods only exist in our minds as ideals (the
idealist position). The realist position holds that Epicureans understand the gods as existing as physical and immortal beings made of atoms that reside somewhere in reality. Instead, the gods live in what is called the
metakosmia, or the space between worlds. Contrarily, the idealist (sometimes called the "non-realist position" to avoid confusion) position holds that the gods are just idealized forms of the best human life, and it is thought that the gods were emblematic of the life one should aspire towards. The debate between these two positions was revived by A. A. Long and David Sedley in their 1987 book,
The Hellenistic Philosophers, in which the two argued in favour of the idealist position. While a scholarly consensus has yet to be reached, the realist position remains the prevailing viewpoint at this time. ==Legacy==