Plato is the first classical philosopher. Born in 427(428) age before c. He made a first complete philosophical system. Of course, it's not the same with the German classical philosophical systems but it can be divided into a couple of parts that are connected with each other by mental strings.
First of all, Plato wrote his own ontology. The world consists of three parts - first one, and it's true being - the world of ideas. For Plato we can call something true being only if this something is an absolute one, it means that it is something immortal, unchangeable and doesn't care about any influence from time and space dimensions. These absolute beings Plato calls Ideas or Eidos. From these ideas, we can build ontological system. If absolute beings exist in its separate world - we have to create a place where this idea will become available for our perception. So we've got the second ontological part - things world or world of copies (simulacrum as it was described later in the 16th century). Absolute ideas just projecting to this copies world, so if somewhere idea of the table exists than the table on your kitchen just copy of this absolute idea. Let's stop here. When somebody tells you that here, in the world everything is relative and you can't be sure about nature of things, be sure that you're talking with a person, who uses idealistic world understanding. And if this person tries to speak with you about scientific methods - he just doesn't understand what he's talking about. It's not fair in the case of multiverse world understanding. We're dealing with things in copies world by the mix of our thoughts and senses. When we're dividing the world to real one and copies one, and real one contains immortal ideas - we have to fix in our minds that in there is nothing immortal in the world of copies. World of copies is changing all the time.
Plato found third ontological part - space. Space is immortal, unbreakable, everlasting. Space - home for everything. Space can't be felt by senses, only by mind force, you can't believe in space, you know it "a priori". It seems as a quite simple for understanding but there are tons of underwater stones such as the meaning of the idea. For sure, Plato's ideas are not just terms or meanings of things, it is also their reasons and goals. In dialogue "Parmenides", Plato criticizes dualistic world understanding and opposing two worlds - real (Eidos) and copies. Plato's words aren't dualistic cause they are existing in a strong connection. For simplification of the understanding, this fact imagines movie "The Matrix". The matrix is produced by the real world, it's not the selfish one. Moreover, Plato's ideas starting the discussion about the fairness of mono- things, such as absolute, for example, god. Cause if the thing is existing, it can't be mono, it becomes poly in the moment of creation in the world of copies. If it's mono only in the world of ideas - it doesn't exist, cause you can't even think about it, cause our imagination is anthropomorphic.
Actually, Plato is quite illogical. We'll see it next, speaking about Plato's soul, government, and ethics.
Plato's ontological system is very unstable; ontology like itself is a very complicated thing, so I recommend using the most interesting ontological system to understand previous ones by the differential method. Try existential-ontological system by J.P.Sartre. It's not perfect, but imho - best. In the end of the historical ontological review, we will try to improve Sartre's ontology.
First of all, Plato wrote his own ontology. The world consists of three parts - first one, and it's true being - the world of ideas. For Plato we can call something true being only if this something is an absolute one, it means that it is something immortal, unchangeable and doesn't care about any influence from time and space dimensions. These absolute beings Plato calls Ideas or Eidos. From these ideas, we can build ontological system. If absolute beings exist in its separate world - we have to create a place where this idea will become available for our perception. So we've got the second ontological part - things world or world of copies (simulacrum as it was described later in the 16th century). Absolute ideas just projecting to this copies world, so if somewhere idea of the table exists than the table on your kitchen just copy of this absolute idea. Let's stop here. When somebody tells you that here, in the world everything is relative and you can't be sure about nature of things, be sure that you're talking with a person, who uses idealistic world understanding. And if this person tries to speak with you about scientific methods - he just doesn't understand what he's talking about. It's not fair in the case of multiverse world understanding. We're dealing with things in copies world by the mix of our thoughts and senses. When we're dividing the world to real one and copies one, and real one contains immortal ideas - we have to fix in our minds that in there is nothing immortal in the world of copies. World of copies is changing all the time.
Plato found third ontological part - space. Space is immortal, unbreakable, everlasting. Space - home for everything. Space can't be felt by senses, only by mind force, you can't believe in space, you know it "a priori". It seems as a quite simple for understanding but there are tons of underwater stones such as the meaning of the idea. For sure, Plato's ideas are not just terms or meanings of things, it is also their reasons and goals. In dialogue "Parmenides", Plato criticizes dualistic world understanding and opposing two worlds - real (Eidos) and copies. Plato's words aren't dualistic cause they are existing in a strong connection. For simplification of the understanding, this fact imagines movie "The Matrix". The matrix is produced by the real world, it's not the selfish one. Moreover, Plato's ideas starting the discussion about the fairness of mono- things, such as absolute, for example, god. Cause if the thing is existing, it can't be mono, it becomes poly in the moment of creation in the world of copies. If it's mono only in the world of ideas - it doesn't exist, cause you can't even think about it, cause our imagination is anthropomorphic.
Actually, Plato is quite illogical. We'll see it next, speaking about Plato's soul, government, and ethics.
Plato's ontological system is very unstable; ontology like itself is a very complicated thing, so I recommend using the most interesting ontological system to understand previous ones by the differential method. Try existential-ontological system by J.P.Sartre. It's not perfect, but imho - best. In the end of the historical ontological review, we will try to improve Sartre's ontology.