I was studying theories of perception for my PHI101 course, but did not like to study lecture notes, i rather searched wikipedia. Here’s some theories of perception that i put together from wikipedia:

Common Sense Realism

Common Sense Realism / Naïve Realism / Direct Realism is a common sense theory of perception. Most people, until they start thinking philosophically are naïve realists. Naïve realism holds that the view of the world that we derive from our senses is to be taken at face value: there are objects out there in the world, and those objects have the properties that they appear to us to have. If I have an experience as of a large apple tree, then that’s because there’s a large apple tree in front of me. If the apples on the tree appear to me to be red, then that’s because there are objects in front of me – apples – that have the property redness. In other words, naive realism claims that the world is pretty much as it appears to our senses.

Naïve Realism has serious problems, among which is the problem of the variability of perception. The same object may appear differently to different people, or to the same person at different times. The apples may appear to be red in the daytime, but at dusk they are a shade of gray. If naïve realism is to be taken seriously, and colors are out there in the world, then apples regularly change color depending on how much light is around them. It is much more plausible, though, to think that the apples are the same as they ever were, that all that has changed is our experience of them.

Naïve realism is also used as a synonym for realism, the belief that physical objects continue to exist when they are no longer perceived.

Skepticism

In philosophy, skepticism (Greek: skeptomai, to look about, to consider) refers more specifically to any one of several propositions. These include propositions about

• The limitations of knowledge
• A method of obtaining knowledge through systematic doubt and continual testing
• The arbitrariness, relativity, or subjectivity of moral values
• A method of intellectual caution and suspended judgment
• A lack of confidence in positive motives for human conduct or positive outcomes for human enterprises, that is, cynicism and pessimism (Keeton, 1962)

Representative Realism

Representative Theory of Perception is a philosophical concept, largely developed by Bertrand Russell. It does, unlike naïve realism, take into account sense data (the way in which the object is interpreted) – this induces the veil of perception wherein we are unsure the table we look at exists due to there being no direct objective proof of its existence. In other words, the table I’m looking at appears to have a particular shape to me, due to my angle of vision, and to have a particular color due to the way in which the light bounces off it relative to my position, and that appearance differs from the appearance of the table as seen by the person next to me. Each of us sees not the actual table, but an appearance of it that merely represents an actual table out there.

The representative theory of perception states that we do not perceive the external world directly; instead we perceive our personal interpretation of an object by way of sense data. A naïve realist assumes she sees the dog upon perceiving a dog, whereas a representative realist assumes she sees a sensory representation of the dog upon perceiving a dog.

We perceive a representation of reality (not the reality itself).

Idealism

Idealism is an approach to philosophical enquiry that asserts that direct and immediate knowledge can only be had of ideas or mental pictures. Objects that are the basis of these ideas can only be known indirectly or mediately. Idealism is often contrasted with materialism, both belonging to the class of monist as opposed to dualist or pluralist ontologies. (Note that this contrast between idealism and materialism is approximately as to whether the substance of the world is at base mental or physical).

Phenomenalism

In epistemology and the philosophy of perception, phenomenalism is the view that physical objects do not exist as things in themselves but only as perceptual phenomena or sensory stimuli (e.g. redness, hardness, softness, sweetness, etc.) situated in time and in space. In particular, phenomenalism reduces talk about physical objects in the external world to talk about bundles of sense-data.

The most perspicuous formulation of phenomenalism is to be found in the transcendental aesthetics of Immanuel Kant. According to Kant, space and time, which are the a priori forms and preconditions of all sensory experience, “refer to objects only to the extent that these are considered as phenomena, but do not represent the things in themselves”.