Skip to main content
K12 LibreTexts

2.4: Plato

  • Page ID
  • \( \newcommand{\vecs}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} } \)

    \( \newcommand{\vecd}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash {#1}}} \)

    \( \newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\)

    ( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\)

    \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\)

    \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\)

    \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\)

    \( \newcommand{\Span}{\mathrm{span}}\)

    \( \newcommand{\id}{\mathrm{id}}\)

    \( \newcommand{\Span}{\mathrm{span}}\)

    \( \newcommand{\kernel}{\mathrm{null}\,}\)

    \( \newcommand{\range}{\mathrm{range}\,}\)

    \( \newcommand{\RealPart}{\mathrm{Re}}\)

    \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\)

    \( \newcommand{\Argument}{\mathrm{Arg}}\)

    \( \newcommand{\norm}[1]{\| #1 \|}\)

    \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\)

    \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\AA}{\unicode[.8,0]{x212B}}\)

    \( \newcommand{\vectorA}[1]{\vec{#1}}      % arrow\)

    \( \newcommand{\vectorAt}[1]{\vec{\text{#1}}}      % arrow\)

    \( \newcommand{\vectorB}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} } \)

    \( \newcommand{\vectorC}[1]{\textbf{#1}} \)

    \( \newcommand{\vectorD}[1]{\overrightarrow{#1}} \)

    \( \newcommand{\vectorDt}[1]{\overrightarrow{\text{#1}}} \)

    \( \newcommand{\vectE}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash{\mathbf {#1}}}} \)

    \( \newcommand{\vecs}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} } \)

    \( \newcommand{\vecd}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash {#1}}} \)


    Plato’s Theory of the Ideal Forms

    Plato describes the death of Socrates in the dialogue, the Phaedo. In that dialogue Plato becomes the first human to set into written form an attempt to prove that human beings have souls which are spiritual and immortal. Many cultures have such a belief. It can be found all around the world. However, the Greeks were the first to attempt to offer a proof for its existence and a proof based upon reasoning. In order to understand the Phaedo and its arguments one must first be aware of Plato’s Theory of the Forms. Plato makes use of them in attempting to prove that the soul exists and that it survives the death of the body.

    In the Phaedo Plato uses the Theory of the Forms. Aristotle made it clear that Socrates did not use that theory, it was developed later by Plato. So what is most likely is that Plato probably began the dialogue right after the death of Socrates. He must have taken notes. He was not present at the death; he was ill. He probably recorded what others told him occurred and then years later returned to the notes and finished the dialogue. So the Phaedo is a mix of what Socrates actually said and words Plato placed into the mouth of Socrates to complete the arguments and offer stronger ones consistent with Plato’s views. It is likely a dialogue from Plato’s middle period of creativity (see mini-lecture on Plato’s Dialogues). The dialogue contains four different arguments to prove the existence of the soul. Socrates states at the conclusion of the first that it is sufficient. The other three were probably added later by Plato and utilize references to Plato’s theory of the forms.

    The Theory of the Forms

    For many years I presented this theory in class utilizing a series of questions and practical demonstrations. In this medium we shall attempt to get as close as possible to that. We start off with a simple question:

    What is this a picture of?

    f-d:cc412c0e8f6e4c0812af0b43fc62e42a3b9324864d1b59a01abfb4c8 IMAGE_THUMB_POSTCARD_TINY IMAGE_THUMB_POSTCARD_TINY.1

    You probably answered that it is a chair. And you are correct! Now answer this question: What is a chair?

    You may have answered “ It is something that you sit on” Over the years everyone who volunteers the answer in class has said that. It seems so obvious! A chair is something that you sit on. Now look at this photo and consider that answer.

    f-d:b20d4e1fce29e520261cc14452301e2d8b8fdda2fbe49eed878bb8e0 IMAGE_THUMB_POSTCARD_TINY IMAGE_THUMB_POSTCARD_TINY.1

    Arguments for the Existence of the Soul

    Now just because someone sits on a desk it doesn’t mean it is a chair but a chair can’t be just something that you sit on. You can sit on many things; desks, stairs, large rocks, benches, tree stumps, cars, your little brother or sister, etc….

    What is a chair?

    By now you should realize that the original simple answer, “Something that you sit on” , is wrong or at least not really correct. We can do better than that. You may now be thinking that a chair is something that was made to have people sit on it. Further to prevent a human or other animal from being a chair you should also realize that whatever a chair is--it is non-living matter. It is inanimate. In a classroom someone or other, by now, is offering the following as the definition of a chair: A chair is an inanimate object made for the purpose of having humans sit on it. Better yet: A chair is an inanimate object expressly designed and manufactured for the purpose of having humans sit upon it.

    Now if you agree with that definition being much better than “Something that you sit on” We are off to a good start in attempting to understand Plato’s Theory of the forms.

    A chair is an object that humans can sit on, we can also stand on them to get your picture taken!.

    f-d:25fddc1aab80076dd63fd0984ac10098092f5d30eabd378fa42a2809 IMAGE_THUMB_POSTCARD_TINY IMAGE_THUMB_POSTCARD_TINY.1

    We can use them to hold a door open. We can do a number of things with them but we realize that they are made for one purpose in particular. Chairs do not need to have four legs. They can have three legs , two legs even one leg or no legs at all. Chairs do not need to be blue or brown or green or any color at all. Chairs do not need to be made of wood or metal . Chairs could be made of clear glass, several large blocks. To understand what a chair is you must abstract from any one particular chair and use your mind to get at the essence of a chair. Its essence is in its purpose. Before the first chair was ever made by a human that human probably got tired of sitting on piles of animal hides or tree stumps or large rocks. That human had the idea of making something to sit on. The idea of the chair preceded its existence. The idea of the chair contains its purpose.

    Theory of Knowledge

    Plato believed that just as you have realized what a chair is, so to can all humans do so by thinking, by using their minds. Plato believed that a human achieves knowledge by recollecting what was known before that human’s soul entered the body. There is a realm of eternal forms, of ideas and ideals that never change. These ideal forms universe, what it is. When humans come to have knowledge of something it is recollecting the ideal form. So Socrates could lead people through questioning to an understanding and knowledge of something without needing to lecture or tell a person what the answer is. Plato demonstrates this in the Meno, in which Socrates leads a person with no knowledge of geometry to correct answers concerning geometric shapes by asking questions. So this universe is what it is to the degree it participates in the realm of the forms. The particular things are what they are because the have the forms in them or behind their creation and existence. The essence of a thing is what we know and that essence is its form. The essence is also its purpose. Knowledge consists of awareness of the essence, the eternal form that makes something what it is. The soul existed in the realm of the eternal forms before it entered the human body. It had all knowledge. As it enters the body the soul becomes confused as it experiences particular things that have particular shapes and colors and other attributes that the ideal form does not have. A person knows what a chair is, its essence, its form, before that person is ever born. A person becomes confused after entering the body and seeing particular chairs with their particular forms and hearing people speak a particular human language. Other humans attempt to get that person to identify a sound like “Chair” or a series of letters like ”c-h-a-i-r “ with a particular object, such as a brown, wooden, four legged, chair with a straight back. The child makes the identification and the mind of the child is led away from the knowledge of the pure essence of what a chair is. The child knows the essence of mother and father and table and tree and all things before it is born but gets confused by people uttering sounds like ”mommy” and “mamma”, “say “ mommy, baby” “say mommy”.

    Plato on the Forms

    Plato was the first to put into writing a theory of how it is we have knowledge and to explain how we make mistakes. For Plato knowledge is recollecting (Anamnesis), remembering what we were in contact with (knew) before our souls (minds) entered our bodies. Plato accepted an idea that many Greeks believed: reincarnation. So he believed that we live in some form before we enter the body and that we survive after leaving the body and might enter another body to experience another lifetime. He developed this theory of the forms and used it to explain knowledge.

    Things are what they are because of their forms. We know the form and not the thing itself. We know the group or category a thing fits into, participates in, is made real by and not the concrete particular thing. What we know about a thing such as:

    f-d:cc412c0e8f6e4c0812af0b43fc62e42a3b9324864d1b59a01abfb4c8 IMAGE_THUMB_POSTCARD_TINY IMAGE_THUMB_POSTCARD_TINY.1

    That it is a chair. That it is a member of a group or set or category of things called ”chair” because it has the same essence, purpose or form. “Chair” is also a member of another set or form called “furniture” again because it shares in the same essence as other members of that set such as; “table” and “lamp”.

    Plato believed that all people can reason and it is reason that can cause a person to have knowledge, to move away from focusing on the particular concrete object and to recollect the universal abstract essence or form of the thing. That knowledge was necessary for understanding and for wisdom. The senses are a distraction for humans and often confuse humans. For genuine understanding a human needs to get beyond the senses to reach the truth through reasoning. Reasoning would have us deal with ideas and not the particular phenomenal aspects of the object. If we keep looking at the four legs of a chair we will not come to understand truly what a chair is.

    Plato believed that just as all people can come to understand and agree that: 2+3=5, then all people can come to understand that a chair is an inanimate object designed and manufactured for the purpose of having humans sit on it.

    He believed that with proper concentration and reasoning all people would also come to understand the essence of: Truth, Beauty, Goodness, Temperence, Courage, Justice, Love, Friendship and all the Virtues and all the important matters for humans to know.

    He thought this because he thought that all those words referred to ideal forms that are in all of us and need only the proper thinking, led by questioning and guided by dialectical reasoning.

    Plato’s contribution to the world of thought was this Theory of the Ideal Forms. They would explain how things come to be as they are, the order of the universe, how we come to know things, how we make mistakes, how we should live our lives. It is the form and not the particular thing that is important, virtue and not the particular life that is important. To be in a human body and thus to be ensnared by its distractions and temptations was an embarrassment to Socrates and to Plato. Humans need to get out of their bodies (to die a bit) through reflection and reasoning to get at the truth and understanding. The body misleads us, the senses confuse us, our perceptions are not to be trusted.

    Things Are Not What They Appear to Be


    I can swear to you that for me still, the sun looks to me as if it is not that hot, not that big and not that far away. And I swear it moves! However, I have “learned” that the truth is quite the opposite. But I swear that the earth does not look or feel as if it is moving. It does not look round. To me the earth looks flat and stationary. But I am informed that it is actually spherical and rotating as it moves around the sun. It rotates at over 17,000 miles an hour. Imagine that! Well I can’t imagine it. I can not see it. I have no feeling for it. And yet it is true?

    If you are inclined to dismiss Plato’s theory, consider this: much of what you know and believe and much of modern science owes a great deal to Plato’s theory. The laws of Nature are discernible to those who can detach from the particular observations and look for patterns, look for forms in the data. It was Plato who commanded us to measure things and to look for what only reason could see operating in the universe in order to discover (remember) the truth and gain knowledge!

    View an Excerpt from a Timaeus a dialogue by Plato below.

    I will therefore now proceed to speak of the higher use and purpose for which God has given eyes to us. The sight in my opinion is the source of the greatest benefit to us, for had we never seen the stars, and the sun, and the heaven, none of the words which we have spoken about the universe would ever have been uttered. But now the sight of day and night, and the months and the revolutions of the years, have created number, and have given us a conception of time, and the power of inquiring about the nature of the universe; and from this source we have derived philosophy, than which no greater good ever was or will be given by the gods to mortal man. This is the greatest boon of sight: and of the lesser benefits why should I speak? even the ordinary man if he were deprived of them would bewail his loss, but in vain. Thus much let me say however: God invented and gave us sight to the end that we might behold the courses of intelligence in the heaven, and apply them to the courses of our own intelligence which are akin to them, the unperturbed to the perturbed; and that we, learning them and partaking of the natural truth of reason, might imitate the absolutely unerring courses of God and regulate our own vagaries. The same may be affirmed of speech and hearing: they have been given by the gods to the same end and for a like reason. For this is the principal end of speech, whereto it most contributes. Moreover, so much of music as is adapted to the sound of the voice and to the sense of hearing is granted to us for the sake of harmony; and harmony, which has motions akin to the revolutions of our souls, is not regarded by the intelligent votary of the Muses as given by them with a view to irrational pleasure, which is deemed to be the purpose of it in our day, but as meant to correct any discord which may have arisen in the courses of the soul, and to be our ally in bringing her into harmony and agreement with herself; and rhythm too was given by them for the same reason, on account of the irregular and graceless ways which prevail among mankind generally, and to help us against them.

    Thus far in what we have been saying, with small exception, the works of intelligence have been set forth; and now we must place by the side of them in our discourse the things which come into being through necessity-for the creation is mixed, being made up of necessity and mind. Mind, the ruling power, persuaded necessity to bring the greater part of created things to perfection, and thus and after this manner in the beginning, when the influence of reason got the better of necessity, the universe was created. But if a person will truly tell of the way in which the work was accomplished, he must include the other influence of the variable cause as well. Wherefore, we must return again and find another suitable beginning, as about the former matters, so also about these. To which end we must consider the nature of fire, and water, and air, and earth, such as they were prior to the creation of the heaven, and what was happening to them in this previous state; for no one has as yet explained the manner of their generation, but we speak of fire and the rest of them, whatever they mean, as though men knew their natures, and we maintain them to be the first principles and letters or elements of the whole, when they cannot reasonably be compared by a man of any sense even to syllables or first compounds. …..This new beginning of our discussion of the universe requires a fuller division than the former; for then we made two classes, now a third must be revealed. The two sufficed for the former discussion: one, which we assumed, was a pattern intelligible and always the same; and the second was only the imitation of the pattern, generated and visible.

    Philosophical Applications

    f-d:8b0d44895d1f81666f9ee08e1867b89f6556d19df19920cc99176880 IMAGE_THUMB_LARGE_TINY IMAGE_THUMB_LARGE_TINY.1

    Plato: Philosophy, the Process

    A chance to do a little Philosophy; Platonic style! What is Love? What is its essence?

    Short answer: Follow a Platonic approach to arrive at the essence of love. Does it have necessary or sufficient conditions?


    Vocabulary Quizlet 2.4

    This page titled 2.4: Plato is shared under a CK-12 license and was authored, remixed, and/or curated by CK-12 Foundation via source content that was edited to the style and standards of the LibreTexts platform; a detailed edit history is available upon request.

    CK-12 Foundation
    CK-12 Foundation is licensed under CK-12 Curriculum Materials License