It would not be an exaggeration to say that the distinction between
appearance and reality is, and has always been, one of the principal
focal points of philosophy. Although the question relates to intricate
relationships among theories of knowledge, ontology, and truth, the
chief question raised by the distinction is epistemological: How can
people know the nature of reality when all that people have immediate
access to are appearances? Broadly speaking, responses to the question
fall into one of three classes: Those that argue that observers are
unavoidably "cut off" from reality, those that argue that there is some
way of "getting at" reality through the appearances, and those that
reject the distinction. This article will examine some of the most
prominent statements of each position. Surveying these positions will
illustrate the way in which any approach to the issue forces a
philosopher to take a stand on a wide set of philosophical issues, which
explains why the distinction has formed a starting point for many of
the greatest philosophical systems in the history of Western philosophy.
Motivation for the distinction
There are both common-sense and historically contingent sources of motivation for the distinction between appearance and reality.
Because of everyday experience, people frequently find themselves in situations where they are presented with appearances known to be misleading. Some instances of this are dramatic, such as crafted perceptual illusions that immediately come across as unbelievable. In other cases, the knowledge that the appearances are misleading requires more experience and investigation (e.g. rainbows). In general terms, these are cases which one can report in a sentence of the form, "It seemed to me that P, but really, it's not the case that P." Further, one might compare two instances where things seemed to be the same way, whereas there was a difference in reality. One way to report that would be to say that the appearances were the same in both instances, though the underlying reality differed.
Though the above motivations for the distinction are common to all human experience, philosophical discussions of the distinction have been fueled by scientific advances which seemed to yield the result that certain features of experiences are only "appearance-deep." The gradual acceptance of Copernicus' heliocentric model of the solar system in the sixteenth and seventeenth centuries came with the realization that the apparent rising and setting of the sun were, in fact, illusions. This fact made a deep impression, and lead towards a new philosophical picture of the universe in which things like colors and sounds were deemed "mere appearances," while only properties susceptible to geometric analysis (such as shape and motion) were kept as part of the picture of true reality.
More recent developments in science have had similar effects. Einstein's theories of relativity, as well as advances in quantum mechanics, have led some scientists and philosophers to claim that even three-dimensional space and a universal, uniform temporal structure are mere appearances. Various feminist and postmodernist thinkers have gone so far as to claim, sometimes on the basis of scientific advances, that objective reality itself is, to some degree, an illusion (for an important clash between those thinkers and their philosophical opponents, see the debate ignited by physicist Alan Sokal's 1996 Hoax). The actual argumentative path between the scientific advances and such conclusions is extremely subtle, however. It is a matter of substantive debate whether or not the fact that a given scientific model has a certain type of explanatory power, which implies that it tells scientists something about which objects or properties are real and which are merely apparent.
When faced with the distinction between appearance and reality, and the worry of how one can know reality on the basis of the appearances with which one is presented, the most straightforward response may be to simply deny that people have any reliable access to reality. This sort of position is often described as "skepticism."
In the Hellenistic period in ancient Greece, there were two prominent schools of thought which identified themselves as skeptics: The Academics and the Pyrrhonists. Both drew inspiration from the early dialogues of Plato, which typically involved the character Socrates demonstrating that someone who claimed to be an authority on a certain subject in fact had no knowledge. The Academics believed that the gap between appearance and reality was, in principle, unbridgeable—no claims concerning reality itself, other than its unknowability, were permissible. The Pyrrhonist position was somewhat weaker, for they made no claims to certainty about the nature of the gap. Instead, they aimed for a practical ideal, in which one refrained from all judgments, and so would never affirm something false.
Ancient skepticism exerted great influence on later European philosophy. Descartes and Berkeley proposed philosophical systems aimed at combating skepticism (see below), while others such as Pierre Bayle took on the task of defending it. Skepticism of some form or another remained a central topic in twentieth century epistemology, as witnessed by the work of philosophers such as Peter Unger.
Before the development of skepticism as a general school of thought, the Athenian philosopher Plato offered a classic articulation of the appearance/reality distinction, while indicating what he found to be the way to achieve knowledge of reality. Plato's picture is a rationalist one, relying on a faculty of reason that was independent of the senses, and articulated the basic elements of the philosophical systems of later thinkers such as Descartes and Leibniz.
In Book VII of his Republic, Plato presents "The Allegory of the Cave." The Allegory begins by describing what Plato takes to be an analogue of the epistemic position in which the majority of people belong to: People are inside a cave, facing away from a fire, and see only the shadows of objects which are moving behind them. Because they see nothing other than these shadows, they mistakenly assume that these shadows are real objects, and put much effort into watching them and discovering their details. Yet, Plato asserts, it is possible for someone to escape this position and leave the cave. Such a person would at first be blinded by the light of the real sun, yet would start acquiring knowledge of true things and realize the absurdity of the shadow-examination that continues in the cave.
Explaining the meaning of each of the elements of the Allegory is a significant interpretive challenge, but the basic ideas are straightforward. The shadows correspond to the appearances with which our senses present us. The aspect of the story where the shadows are generated by objects illuminated by a light other than the sun is meant to indicate that they are somehow produced by real things, but in a very indirect manner. Leaving the cave is meant to correspond to a philosopher's ability to cease relying on his senses as a guide to reality and instead use his faculty of reason. Reason not only puts him in epistemic contact with the true elements of reality (the "Forms" of Plato's metaphysics), but also allows him to understand the degree to which appearances differ from these elements, and how they are produced by them.
What is distinctive about Plato's approach to the appearance/reality distinction, especially in contrast to later figures, is the degree of distance by which he believes appearances are separated from reality. Reality, for Plato, isn't composed of the sort of things one might have intuitively thought it was, such as particular rocks and animals, but rather of a set of "pure" objects knowable by philosophical inquiry (such as "the Beautiful itself" and "the Good itself"). Putting the matter somewhat loosely, it might be said that Plato presents a philosophical system in which observers are able to understand reality through (or despite) appearances simply because reality is just the sort of thing one's intellect is capable of uncovering.
In the Modern period of philosophy, the canonical expression of the distinction between appearance and reality, and of the ensuing threat posed to knowledge, is found in Rene Descartes' Meditations on First Philosophy (originally published in 1641). Descartes highlighted the distinction with a simple but powerful imaginative project. He asked how much divergence there could conceivably be between the appearances he encountered and the world in which he existed. The answer is made vivid by his description of a scenario in which he is the subject of deliberate and near-complete deception by a powerful "evil genius" (see Meditation I), a scenario which no appearances give him any grounds for ruling out as a genuine possibility.
Descartes eventually concludes that the gap between appearance and reality is surmountable, and that he can rule out the evil genius scenario. He reaches this conclusion by arguing from the fact that he has an idea of an omnipotent, benevolent God to the existence of that God, and then by arguing from the existence of such a God to two claims: (1) since God is responsible for the world and its appearances, it would be incompatible with God's goodness if there were to be a dramatic difference between the two, and (2) since God is responsible for Descartes' own faculties, he must be capable of knowing the truth about the world around him.
Though Descartes' arguments made a massive impact on the philosophical landscape, they were by no means universally accepted. There is a general agreement that his proofs for God's existence are much less compelling than he took them to be. Yet, for those who continued to accept the fundamental distinction in Descartes' terms, it was unclear what else besides a knowable, benevolent God could fill the needed role.
Over a century after the publication of Descartes' Meditations, a more subtle answer to the problem was provided by Immanuel Kant, one which would inspire the tradition known later as "German Idealism" (to be contrasted with the idealism of Bishop Berkeley, discussed below). Kant appears to accept something like Descartes' distinction, yet he poses the issue in terms of an opposition between "objects as they appear" and "objects as they are in themselves." Observers have no real knowledge of objects as they are in themselves, Kant claims, but it was a mistake on Descartes' part to think that they ever wanted such knowledge. Properties like spatial extension, temporal duration, and causal connection, Kant argues, properly belong to the realm of appearances. Because appearances are in some sense "in us," and people are capable of knowing themselves, this opens the possibility of knowing whether objects really are spatially extended, causally related, etc. Kant holds that much of reality remains unknowable, yet he takes this to be a desirable result, for it precludes scientific considerations (which only concern the appearance-based properties of objects) from ever ruling out freedom of the will or the existence of God, even while the actuality of the latter two remain unknowable.
In twentieth century philosophy, a number of related responses have been considered. One particularly noteworthy suggestion is that, as things are, what humans lack is not knowledge of reality, but knowledge that we have such knowledge.
Responses that reject the distinction
The Irish Bishop George Berkeley, like Descartes, saw skepticism as a serious, but surmountable, philosophical threat. Unlike Descartes, however, Berkeley believed that it was a mistake to distinguish appearances from reality in the first place. Following his predecessor John Locke, Berkeley puts the discussion in terms of "ideas," where these include both the appearances one encounters in sensory perception, as well as the mental entities involved in one's thoughts. Berkeley's fundamental claim (developed in his Principles of Human Knowledge (1710) and in his Three Dialogues between Hylan and Philonous (1713)), was that all that exists are minds and the ideas they have. Skepticism about the external world, he argued, arose from a wholly unwarranted positing of "material substance," understood as something distinct from ideas and minds, which is somehow represented by ideas and thereby mediately encountered by minds. Once observers assume such things exist, and that they are the objects of one's knowledge, Berkeley believes that people will inevitably conclude from the mediacy of their awareness of those objects to a lack of true knowledge on the observer's part.
Yet, Berkeley argued, it was an unwarranted break with common sense for philosophers to assume the existence of material substance, and in doing so to create the distinction between appearance and reality. The objects that populate the world aren't something to be accessed by means of ideas, rather, they are those ideas. Berkeley has a simple argument for this claim:
- People perceive objects immediately.
- The only entities people can perceive immediately are ideas.
- Therefore, objects are ideas.
Berkeley's system is strikingly elegant. Unsurprisingly, however,
he is hard-pressed to account for the phenomena that originally
motivated the distinction, such as perceptual illusions and scientific
advancement. Ultimately, Berkeley appeals to God, as causal source of
the ideas, who maintains a certain order among them that one can only
gradually come to understand.
While Berkeley rejected the appearance/reality distinction by making reality more mental (and so, in a sense, claiming that all there is are appearances), others have rejected the distinction by attacking the notion of "appearances" or "ideas" that is in play. Antoine Arnauld argued for such a position in the wake of Descartes' Meditations, but the first sustained attempt to develop the position came from Thomas Reid, a Scottish minister and professor. In the second essay of his Essays on the Intellectual Powers (1785), he specifically attacked the intelligibility of the "ideas" assumed by Locke and Reid, and attributed philosophical worries about the gap between appearance and reality to the assumption of such mental entities. When one perceives an object, Reid claimed, they do so directly, not by means of any idea or appearance. Such ideas would amount to a veil between observers and the world, whereas in truth there is no such barrier. Like Berkeley, however, Reid was hard-pressed to explain away illusions, and ultimately ended up assuming the existence of "sensations"—mental entities with some similarity to Lockean ideas. Nevertheless, many contemporary philosophers have found his attempt compelling.