IB Philosophy 3.2.2 Theories of Perception Notes

Objectivism and Direct Realism

Objectivism and the Challenge to Direct Realism

1. Topic 3.1.3 examined perception as one of the three primary sources of knowledge, noting its strengths and vulnerabilities. Topic 3.2.1 introduced the argument from illusion, which challenges the reliability of perception by pointing to cases where our senses misrepresent reality.
2. This topic examines the major philosophical theories that attempt to explain how perception relates to the external world.
3. The IB syllabus frames this topic around the question: "How reliable is perception as a source of knowledge?" The answer depends on which theory of perception we adopt. The syllabus requires engagement with two fundamental distinctions: subjectivism versus objectivism, and the theories of idealism, phenomenalism, and perspectivism.
4. Objectivism about perception holds that there is a mind-independent external world that perception gives us access to. The properties we perceive (colour, shape, texture, sound) belong to objects themselves, not to our minds.
5. This view aligns with common sense: most people naturally assume that the world they perceive is real and that their senses reveal it more or less accurately.
6. Direct realism (also called naive realism) is the most straightforward objectivist position. It holds that when we perceive a red apple, we are directly aware of the apple itself, not of a mental representation of it.
7. There is no intermediary (no "sense datum," no "idea") between the perceiver and the object. Perception is a direct, unmediated contact with reality.
8. Direct realism faces serious challenges from perceptual illusions and hallucinations. As discussed in 3.2.1, a stick looks bent in water, distant towers look round, and dreams can feel indistinguishable from waking life.
9. If perception sometimes misrepresents reality, then we cannot always be directly aware of things as they are, which is the central problem for direct realism.

Indirect Realism, Locke, and the Kantian Synthesis

1. Indirect realism (also called representationalism) responds to these challenges by arguing that we never perceive objects directly. Instead, we perceive mental representations (sense data, ideas, percepts) that are caused by external objects.
2. The external world exists independently of our minds, but our access to it is always mediated by our sensory and cognitive processes.
3. John Locke defended a version of indirect realism by distinguishing between primary qualities (shape, size, motion, solidity) that belong to objects themselves and secondary qualities (colour, taste, smell, sound) that are produced in the mind by the object's primary qualities. On Locke's view, we accurately perceive primary qualities but construct secondary qualities through our sensory apparatus.
4. The problem with indirect realism is the veil of perception: if we only ever perceive our own mental representations, how can we know that they accurately represent the external world? We can never compare our representations with reality itself, because every attempt at comparison involves more representations.
5. This connects to the correspondence theory of truth (discussed in 3.1.2) and the comparison problem it faces.
6. The question of perceptual reliability connects to 1.3.1 (Consciousness, the Self and the World), where we examined how consciousness relates to external reality. It also connects to Kant's distinction between phenomena (the world as it appears to us) and noumena (the world as it is in itself), discussed in 3.1.1.
7. Kant argued that our minds actively shape how we experience the world, because concepts like space, time, and cause-and-effect (which he called the categories of the understanding) are structures our minds impose on raw experience rather than features of independent reality. Kant called this reversal his "Copernican revolution" in philosophy: just as Copernicus showed the Earth moves around the Sun, Kant argued that objects must conform to how our minds work.
8. The implication for perceptual reliability is that we can have systematic, objective knowledge of the phenomenal world (the world as structured by our cognitive faculties), but we can never know things as they are independently of our perception. Perception is reliable within its domain but inherently limited.
9. For IB students, the direct/indirect realism debate provides a framework for evaluating all perceptual knowledge claims. The key question is always: are we perceiving reality itself or a representation of reality?
10. The answer has implications for the reliability of every empirical belief we hold.

Idealism and Phenomenalism

Berkeley's Idealism and the Rejection of Matter