Heraclitus believes that there is no other reality apart from change. Everything else in the universe changes apart from the change itself. Apart from the fact that nothing in the universe remains the same over a period, change also originates from cosmic order. He believes that for everything that exists, their existence is the opposite. He states that no one can step twice in the same river. This statement emphasizes that just as water in a river is always in motion, change happens constantly to both living and non-living things.
Empedocles views are close to modern science. He explains how reality occurs and why it does. According to him, even though true reality cannot be changed, it cannot be viewed as nonexistent. He explains that the basic particles of matter are permanent. These are the earth, fire, air, and water. However, objects of experience are subject to change. He goes on to explain that the changes that object experience emanate from two main forces, which are attraction and decomposition (Moore & Bruder, 2011).
Anaximander’s theory has its basis on natural powers and process (Moore & Bruder, 2011). He believes that the basic substance from which everything else comes from is not only water but also something beyond our knowledge.
He explains that the world was formed from that basic substance being surrounded by a nucleus of fire and mist. The mist at the center turned into solid and became the world, while the fire turned into heavenly bodies and stars. Changes in the intensity of wetness and dryness, hotness and coldness resulted in the seasons.
Parmenides and Heraclitus have different views of reality. According to Heraclitus, change is the main feature of reality. He says that all is fire, which means all things are subject to change. This process is initiated by cosmic order, which is responsible for the harmonious union of opposites. However, Parmenides argues that beings are not subject to change because if it is so, they could be nonexistent beings (Moore & Bruder, 2011). He explains that if beings change, then they would be no beings, which means they would be nonexistent.
According to Protagoras, man is the measure of all things (Moore & Bruder, 2011). This means that a person’s perception of the world is just as true as another’s perception, and thus, knowledge is relative. What one perceives or deems as the truth is about how he/she views that particular subject.
Pythagoras supports the notion that things are numbers. A line can be described as two points and a surface as three points. Surfaces make a solid, which in turn make bodies. Pythagoras holds that all things exist in the form of numbers, but do not originate from numbers, as many Greeks believe. In his perception, Pythagoras believes that there exists a relationship between numbers and things. Everything so long as it can be counted, physical or non-physical participates in the order and harmony of the universe (Moore & Bruder, 2011).
Anaxagoras is known for his contribution to the difference between mind and matter. In reality, he believes that all substances are infinitely divisible. He explains that all substances contain particles in two categories.
One category is of its kind, and the other is of all other kinds of particles. However, the particles of a substance dominate, and that is what differentiates one substance from the other. He believes that the mind is pure and the force behind change. Although the mind acts on matter, it neither creates the matter nor serves a particular purpose.
Among the early Greeks, Empedocles has a reasonable conception of the nature of reality. According to him, the earth, fire, air, and water, which are the basic elements, are unchangeable. However, the four together with the forces of either love or strife interact in different proportions to change the objects of experience. He realizes that knowing how the changes occur is not enough, but also knowing why they do occur is crucial.
Plato criticizes Protagoras’s theory that man is the measure of all things as false. Plato argues that knowledge based on perception is a collection of opinions, which are more of ignorance than true knowledge.
Plato gives an example of that a straight stick put in water appears bent even though it is straight in reality (Moore & Bruder, 2011). Knowledge is not just about a sense of perception, which varies from one sensory organ to the next and continues to exist even when one stops sensing. Hence, Plato affirms that true knowledge is a form.
Plato sees forms as having some unique features. One is that forms are ageless, for example, the beauty. Since its years can neither be counted nor can it cease to exist, beauty is therefore eternal. The second feature is that forms do not change, but always remain the same. For example, no matter how much a circle change, its circumference will always be two pies multiplied by twice the circle radius. The third and final feature, according to Plato, is that it cannot be moved or divided (Moore & Bruder, 2011).
In Aristotle’s view, change does occur for a particular purpose. The essence of a thing is represented by the four causes. First, a thing answers the question on the form, also referred to as the formal cause, which is the form of a thing. Secondly, it answers the question of its composition, which is the material cause. Thirdly, it answers the question of what made it, which is its efficient cause. Fourthly, it answers the question of its purpose, which is its final cause. Things change their potentiality to achieve actuality.
According to Aristotle, it is important to understand what a thing is and also how that particular thing functions. In understanding human beings, he concludes that humans are rational beings, and they have souls, which give them a purpose to fulfill in life.
He explains that human beings assessed things based on the following categories: “quantity, quality, relationships, place, time, posture, constitution, passivity, and activity” (Moore & Bruder, 2011, p. 90). These categories enable one to have knowledge of a thing and have a better understanding of its different aspects.
In Aristotle’s opinion, there can only be one particular form, but many universal forms attached to that particular thing. He states that universals are like circles and are not independent of particulars of round things. He gave another example that different forms could possess the same universals such as beauty or circularity, unlike a particular or an individual form that is round (Moore & Bruder, 2011).
If there were no particulars or individual things, then universal forms would not be in existence. Aristotle viewed forms as part of particulars, which comprise of matter and form.
According to Plato, forms are not experienced in the physical world and thus cannot be experienced by the senses. He explains that forms are the true reality, permanent, eternal, and cannot be divided (Moore & Bruder, 2011). He states that particular things depend on universals, but the reverse is not true. But in Aristotle’s opinion, forms are universals, which were found within particular things (Moore & Bruder, 2011). Form is what makes a thing, but the matter is also necessary.
Aristotle states that everything that exists comes from something. Each thing is composed of some stuff, which is both matter and form. However, according to Gorgias, reality is nonexistence. In his argument, Gorgias says that even if reality was known, it could not be communicated. This means a thought cannot, or an idea cannot just come into existence because it is a thing.
Moore, B. & Bruder, K. (2011). Philosophy: The Power of Ideas. New York: McGraw Hill.