Philosophy - Epistemology - Perception as a source of knowledge

What is the definition of direct realism?

The belief that all objects are mind-independent and humans perceive them directly, that is to say, as they really are.

What are the arguments against direct realism?

• Perceptual variation

• Time lag argument

• Hallucinations

• Illusions

Explain the argument from perceptual variation and explain a counter argument.

The argument from perceptual variation says that every person seems to perceive the same object in a different way. In Bertrand Russell’s ‘The Problems of Philosophy’, he details that a person may see a table as brown, and another may see it as white, depending on where they are standing and where the light hits the table. Therefore, perceived properties and actual properties are not identical.

We can get around this using relational properties. You might say that the table looks white without asserting that the table is brown.

Explain the time lag argument and explain a counter argument.

The time lag argument suggests that we do not perceive objects directly, as some properties are perceived quicker than others. For example, we see the light of a firework before we hear the sound when viewing from far away, as light travels faster than sound, meaning objects are not perceived directly.

A direct realist would say that, although this means that we should give up the naïve view that we perceive objects directly, it does not change that we perceive objects as they truly are, as we are still seeing and hearing the firework.

Explain the argument from illusion and explain a counter argument.

The argument from illusion states that sometimes we do not perceive objects as they really are. A spoon in a glass of water will appear bent due to the refraction of the light, but the bentness of the spoon is not a property that it holds mind-independent of the perceiver, meaning we do not always perceive objects as they really are.

We might bring in relational properties again: the spoon looks bent but this is not actually the case. We also know what causes these kinds of illusions, so science might render this argument weaker.

Explain the argument from hallucinations and explain a counter argument.

The argument from hallucinations says that hallucinations can affect all senses/methods of perception, and they seem to be real objects that are indistinguishable from veridical perception, meaning not every object we perceive directly is mind-independent.

You could argue that hallucination is not a form of perception at all, because it relies on imagination and is not a result of experiencing an external object.

Explain the argument from hallucinations and explain a counter argument.

The argument from hallucinations says that hallucinations can affect all senses/methods of perception, and they seem to be real objects that are indistinguishable from veridical perception, meaning not every object we perceive directly is mind-independent.

You could argue that hallucination is not a form of perception at all, because it relies on imagination and is not a result of experiencing an external object.

What is the problem of using relational properties to counterargue against problems faced by direct realism?

We are somewhat hidden behind the veil of perception (meaning, we can only see the world as it appears to us and we will never know the reality) as we do not know what variation of perception is the correct one, so there may not even be a mind-independent reality at all.

What is indirect realism?

The belief that immediate objects of perception are mind-dependent and represent and are caused by mind-independent objects.

What is sense-data and how does it play a role in indirect realism?

Sense-data is the information we get when we perceive an external object that creates a representation of it in our minds, such as colours or shapes. Sense-data is the mediator between human perception and the physical world, and therefore the mind-dependent sense data is caused by the mind-independent physical object.

What is John Locke’s primary/secondary quality distinction?

The idea that physical objects have primary qualities (which are “utterly inseparable” from the actual object no matter what changes are made) and secondary qualities (which require a perceiving mind and are caused by primary qualities), with a quality being defined as something that has the power to produce an idea in the mind.

What does Locke say are primary and secondary qualities?

Primary:

• Motion

• Solidity

• Extension

• Shape

Secondary:

• Colour

• Smell

• Texture

• Temperature