Plato’s Cave

(Thanks to Dr. Greg Oakes for sharing this information.)


Plato and Socrates

-        Plato, 429-347BCE; Socrates, 469-399BCE

-        Socrates was Plato’s teacher, mentor, and friend.  Plato helped to immortalize Socrates by making him the central dramatic and intellectual figure of his dialogues.  Socrates himself wrote nothing (extant); his method was oral.  Other contemporary sources commenting on Socrates include Xenophon and Aristotle.

-        Socrates’ concerns were primarily moral and spiritual, and he was generally skeptical about our knowledge of these important matters; virtue, for him lay in acknowledging this ignorance.

-        Plato’s career can be defined by reference to Socrates:  “early dialogues” such as the Apology  reflect Socrates’ method and conclusions; a “middle” period (including Republic, from which our excerpt is drawn) establishes Plato’s own positive theories; some later writings (Laws, Statesman, Timaeus) make little or no reference to Socrates.


Plato’s Cave – In General


-        The Cave Allegory is about human knowledge: – about truth, reality, and our access to it.  It provides an excellent symbol for human ignorance, mis-understanding, error, and the difficulties and challenges of education.  The truth is elusive, difficult to find, requiring significant effort and training to obtain.


-        Knowledge is not direct, but mediate:  The reason education is difficult, the reason human life is fraught with error is that we do not access reality directly, but only mediately via the senses.  (I find it very useful to tell students specifically why learning is a challenge; it helps us to understand why we must work so hard at it.  Without such an understanding, we are simply frustrated and bewildered.  Thus, in part, the role of the philosopher returning to the cave.)  More generally, we have the idea of appearance versus reality.  Reality often appears to us in disguise; it is up to us to discern the “true” reality behind appearance.  In other words, the condition of the prisoners in the cave offers a dramatic representation – a metaphor – of our pre-reflective epistemic condition.  This condition is at several removes from actual reality:  ordinary human perception is like the shadow cast by artificial light via a puppet representation of an actual object.  That’s two removes plus an artificial medium of “light” or insight.  More on these details, below.


-        Only reason provides access to truth:  Plato’s second main point is that it is the human intellect, not the senses, that affords knowledge of reality.  Plato thinks that the senses offer only a confused, attenuated vision of reality.  Reason, by contrast, is capable of embracing true reality.  This idea is relatively familiar to our students today, but is seldom articulated clearly and thus rewards emphasis and exploration.


-        The road to knowledge is long, difficult, but vital and continual:  Note the strong imprisonment image in the Cave Allegory:  humans value freedom perhaps above all else, and there is no more powerful bond than those afflicting the mind. Most students are highly responsive to the need for recognizing and surpassing their own mental limitations.


Ironically, instruction is frequently resisted:

o   The Educator:  returning to the Cave.  It is difficult to think of a more compelling metaphor for the thankless labors of the educator than that provided by Plato.  Again, The nature of our process:  we invariably resist the truth – sometimes violently – where it disturbs our present world-view.  Here, as elsewhere, students can readily supply illustrations from their experiences.


o   Note, too, that the process of escaping the Cave is perpetual:  although Plato might have thought otherwise, we evidently never reach a stage when we have secured the truth once and for all.  Rather, we continually face the challenge of self-examination and re-evaluation of the accuracy and completeness of our present understanding.


Some Examples and Illustrations


-        Paradigm Examples:  the basic idea, here, is to provide an example of something clearly real but accessible only by intellect.

o   Physical Science:  This is a great opportunity to get your science students on board early, and then to use that tie to bolster the more general point about reality and our access to it.

§      Most students accept that what chemistry and physics tell us about massive bodies is only remotely related with their appearance.  Thus, compare sense perception (colors, shapes, textures) with a scientific understanding of the objects perceived (light wavelength and refraction, chemical composition, microscopic and sub-microscopic structures).


§      Force, mass, duration, and distance are not, strictly speaking, observable in sense; certainly nothing appears to us in the form of F = m1m2/r2.  That representation is purely intellectual.  Similarly, the duration of an hour is not to be mistaken for the psychological experience of waiting.


§      In general, what we commonly call the “physical” is only the appearance of the physical to us.  To the extent that our physics is correct, the reality described is quite foreign to our senses, and is represented in primarily mathematical terms.


o   Beauty:  Many different things may be beautiful:  physical things such as sunsets, men, women, and flowers; more abstract things such as love, motherhood, an act of faith, or a move in a chess-game; and fully abstract things, such as a mathematical proof, or an idea.  Clearly, Plato reasons, if any one thing makes all these instances of beauty, that thing, beauty, cannot itself be a physical object. And insofar as it is our rational judgment by means of which we know something to be beautiful, we must conclude the thing so known to be an object of the intellect, and thus ideal.


o   Examples of “perfect” geometrical shapes (circles, triangles, etc.) exist only ideally, if at all.  But it is by means of them that we represent and understand the imperfect spatial world around us.


-        More broadly:  There are many aspects of human experience that answer to an illusion/reality paradigm, and Plato’s allegory offers a vivid vehicle for discussing them.  These include the following, the first two of which are Plato’s primary concerns:


o   Our relationship to physical reality via the senses and reason. (Do we all respond the same way to a painting?)


o   Our access to and understanding of moral truth, and other value-laden objects;


o   The relationship between societal norms and the realities of social behavior;


o   The relationship between self and self-identity (or self-construct, or self-concept);


o   The relationship between the media and reality.


The Cave

-        Some general questions about the relationship between reality and human understanding:  What is this relationship, generally speaking?  Why does Plato represent ordinary human understanding as what the prisoners see?  What are some examples of a “disconnect” between appearance and reality?  Can you think of a case in which what you thought or believed or perceived turned out not to be the case?  Discussion of student examples usually sets the basic idea of a problematic truth-appearance relationship.  (One typical example is the “my best friend lied to me.”)


-        In order to bring out the pervasiveness of the truth-appearance disconnect, students should identify different “realms” in which the disconnect occurs.  These correspond to the different basic realms or regions of reality we encounter in experience:  the physical world; the value-laden world; the social world; the self; the world of media (television, the internet). Students should think of these as different, distinct, if related “realities,” to suggest other major facets of human reality, if any, and to consider problems of access specific to each.  What I’m headed towards is discussion of why our access to reality is vexed.


-        That’s the next main question:  why is it so difficult to know the truth?  Try thinking in these terms: look for an account of (a) the nature of the given reality and (b) the nature of our access to it – i.e., the faculty by means of which we know (a), and so (c) an account of why (b) doesn’t always get us (a).  In fact, it will be difficult to articulate (c), because, after all, the nature of reality (a) is elusive, to say the least.  Consider here Plato’s view of either physical or value-laden reality.  (See below.)  Keep in mind that there is much about most everything that we do not yet understand.


-        Ultimately, we conclude that reality is, after all, elusive, difficult to articulate, difficult to know directly or with certainty.  A couple of basic concepts will help you grasp this idea, familiar as it is:


o   The biological origin and nature of the faculties of sense:  the organs of sense and the central nervous system are biological systems – effectively so much goo.  It would be surprising if anything depicted in a fundamentally gooey medium was not mis-perceived by us. 


o   The biological origin and nature of the faculty of reason:  This is to go beyond Plato, and its implications threaten the possibility of human knowledge.  See Nietzsche and other “anti-realist” philosophers who worry that the way we think is not reflective of reality, much less the way we sense.


o   Hormones and feelings: an application of the above, it is notorious that one’s mood can affect how the world appears to us.  For example, feeling angry and so perceiving a loved one as a threat!  Similarly amusing examples can be based on sexual arousal, intoxication, etc.

o   The homunculus:  A homunculus is a person inside a person.  But this is not the nature of human perception.  There is no little man looking out through our eyeholes.  Rather, our access to reality is indirect – we require a representation of reality in my mind, a model of reality, in order to experience it at all.


o   The representation/reality distinction:  This is a generalization of the above:  the terms of or manner in which we experience reality are not identical with the terms or nature of reality per se.



-        Plato is himself most famous, philosophically, for his theory of Forms.  The Forms constitute ultimate reality; they are both the essence and source of reality; knowledge of them is knowledge of Truth.


-        Plato’s Forms are ideal, meaning that they are (a) non-physical and (b) of the same nature as mental objects, generally.  This last is important epistemologically:  since the forms are themselves “idea-like”, it is possible for humans to form direct, noetic (of, relating to, or based on the intellect relationships) with them.


-        Plato’s best examples involve concepts such as beauty and justice.  See above for Beauty.  Similarly, it is easy to see that “justice” doesn’t have any particular sensory appearance, but most students will accept that it is real (e.g., 9/11).


-        Ultimate reality for Plato, then, is ideal, abstract, and also eternal and immutable.  The Forms are in other words essentially (like) ideas.  (Note that ideas don’t change:  to think of the idea of beauty as changing is simply to think of a different idea, such as ugliness.)


-        Where are the Forms?  And When?  Nowhere, and no-when.  (If no one acts justly, does that “eliminate” justice? would there then be no such thing?  Not on this earth, perhaps, no instances; but it would still be true that we should be just.  How can that be, unless there is such a thing, which has no spatiotemporally location?  Note that “ideal”, here, is best interpreted as “not like the material”; otherwise, however, and aside from intellectual accessibility, we know little about it.)


Levels of Knowing and Truth in Plato’s Cave

I.                 Mere appearance:  no representation/reality distinction drawn; unquestioning, unexamined thought; characteristic of the uneducated masses; “seeing is believing”, “you are as you appear to me”

II.               Appearance/Reality distinction drawn.  This is the beginning of ascent from ignorance to knowledge.

III.             Contemplation of reality, truth, by class or kind.

IV.            Possible unity within kinds or classes of truth, reality.  (What is the Real, such that all real things share in it?)



Allegory Element

Epistemological Status

Ontological Status



prisoner understanding

at best, “mere opinion”


common belief


shadows on the cave wall

mere appearance of reality

third-order reality:  presentations in sense to us of second-order reality

images; sights, sounds, tastes, etc., e.g., colors of a sunset


the puppets

immediate source of mere appearance of reality

artificial models of reality

physical objects and processes, e.g., an instance of beauty


artificial vehicle of knowledge


mathematics, science, reason


extra-cave objects

proper objects of knowledge

actual reality

Ideal, immaterial, eternal, immutable reality; Plato’s “forms” – i.e., ideas, e.g., the form of Beauty per se, the law of gravity




source and essence of reality

(Reality per se; the Good?)


Summary of Main Points

-        Our access to reality is indirect – mediated by sense, but found only in reason.

-        This representation/reality dichotomy occurs in every facet of our lives, including the physical, social, familial, interpersonal, personal, etc.

-        Consequently, we must (a) always be aware that our understanding of reality may be in error and so (b) must always strive to look beyond appearance for a rational understanding of reality.

-        The Cave provides a useful mnemonic for the above:  don’t be bound by appearance.