Theories of Perception Revision Notes
Direct Realism (Naïve Realism)
Direct Realism is the theory that we perceive mind-independent objects and their properties directly.
In the case of direct realism, what we perceive is due to the world being that way. For example, if I see
a green apple on the table in front of me, that is because there is a green apple on the table in front
of me existing exactly that way in the mind-independent world. For direct realists, there is a causal
relationship between what we perceive through sense-experience and what is in the real world, The
perceiver is immediately experiencing the object, our perception is unmediated. Objects continue to
exist even when we are not perceiving them, they are independent of the mind, meaning that they
exist in the world. Therefore, they cannot be subjective; however, this idea of objective perception
comes with many issues.
Illusions
▪ The problem of illusions: Illusions occur when a mind-independent object is perceived as having the property
‘F’ when it does not have the property ‘F’. For example, a stick in water appears as having the
property of being bent, when in reality the stick is completely 180. Illusions are misleading
impressions of reality which are subjectively indistinguishable from veridical perception;
essentially, we can’t tell the difference between an illusion and reality. This is a problem for
DR because it argues that we perceive mind-independent objects and their properties
directly, so how can we perceive an object as possessing a property it does not have.
▪ How does direct realism respond to this? The solution to the problem of illusions is relational properties,
these are properties which are only perceived in relation to something else. For example, the stick has the
relational property of ‘looking bent’, as this characteristic is only in relation to being perceived in water. This
relational property does not trivialise the sticks property of being straight, as the stick ‘looks bent’ and ‘is
straight’ so both these properties can exist. These relational properties exist as misperceptions of reality, we
can ‘perceive a straight straw as bent without implying that we directly perceive a bent straw and only
indirectly a straight one.’
Perceptual Variation
▪ Russell’s table: Perceptual variation refers to the differences in the way people perceive the world, Russell
uses the example of a table to discuss this issue (Russell’s table). The corners
of a rectangular table can appear to be to be round when the angel is in fact
90, another example of perceptual variation is colour blindless; someone
who has red/green colour-blindness perceives the colour red as though it is
green. Our perception varies without corresponding changes in the
physical object we perceive, so when someone who is colourblind perceives
a red apple as a green one that is not because the apple suddenly turns green.
▪ Why is perceptual variation a problem for direct realism? Perceptual variation explains that what we
perceive is not identical to what exists in the mind-independent world, which ultimately renders direct
realism as false, because as previously mentioned direct realists argue that we perceive mind-independent
objects directly. If this was truly the case then our perception would correlate with the mind independent
world, our perceptions would be objective. What Russell is showing is that what we are perceiving is sense-
data, sense data is the subjective intermediaries of perception. It is also private, temporary and immaterial.
▪ Direct realists’ response to the problem of perceptual variation: They use the argument of relational
properties again, to defend themselves against perceptual variation, in the instance
of Russell’s table it would be perceived as rectangular by normal observers under
normal conditions; essentially there is a definitive way that something should be
perceived however the conditions for it to be perceived in this way are not always
present. When we see the table as rectangular, we are perceiving its normal shape.
But when we are not perceiving the table as rectangular, we are perceiving its
relational properties.
Direct Realism (Naïve Realism)
Direct Realism is the theory that we perceive mind-independent objects and their properties directly.
In the case of direct realism, what we perceive is due to the world being that way. For example, if I see
a green apple on the table in front of me, that is because there is a green apple on the table in front
of me existing exactly that way in the mind-independent world. For direct realists, there is a causal
relationship between what we perceive through sense-experience and what is in the real world, The
perceiver is immediately experiencing the object, our perception is unmediated. Objects continue to
exist even when we are not perceiving them, they are independent of the mind, meaning that they
exist in the world. Therefore, they cannot be subjective; however, this idea of objective perception
comes with many issues.
Illusions
▪ The problem of illusions: Illusions occur when a mind-independent object is perceived as having the property
‘F’ when it does not have the property ‘F’. For example, a stick in water appears as having the
property of being bent, when in reality the stick is completely 180. Illusions are misleading
impressions of reality which are subjectively indistinguishable from veridical perception;
essentially, we can’t tell the difference between an illusion and reality. This is a problem for
DR because it argues that we perceive mind-independent objects and their properties
directly, so how can we perceive an object as possessing a property it does not have.
▪ How does direct realism respond to this? The solution to the problem of illusions is relational properties,
these are properties which are only perceived in relation to something else. For example, the stick has the
relational property of ‘looking bent’, as this characteristic is only in relation to being perceived in water. This
relational property does not trivialise the sticks property of being straight, as the stick ‘looks bent’ and ‘is
straight’ so both these properties can exist. These relational properties exist as misperceptions of reality, we
can ‘perceive a straight straw as bent without implying that we directly perceive a bent straw and only
indirectly a straight one.’
Perceptual Variation
▪ Russell’s table: Perceptual variation refers to the differences in the way people perceive the world, Russell
uses the example of a table to discuss this issue (Russell’s table). The corners
of a rectangular table can appear to be to be round when the angel is in fact
90, another example of perceptual variation is colour blindless; someone
who has red/green colour-blindness perceives the colour red as though it is
green. Our perception varies without corresponding changes in the
physical object we perceive, so when someone who is colourblind perceives
a red apple as a green one that is not because the apple suddenly turns green.
▪ Why is perceptual variation a problem for direct realism? Perceptual variation explains that what we
perceive is not identical to what exists in the mind-independent world, which ultimately renders direct
realism as false, because as previously mentioned direct realists argue that we perceive mind-independent
objects directly. If this was truly the case then our perception would correlate with the mind independent
world, our perceptions would be objective. What Russell is showing is that what we are perceiving is sense-
data, sense data is the subjective intermediaries of perception. It is also private, temporary and immaterial.
▪ Direct realists’ response to the problem of perceptual variation: They use the argument of relational
properties again, to defend themselves against perceptual variation, in the instance
of Russell’s table it would be perceived as rectangular by normal observers under
normal conditions; essentially there is a definitive way that something should be
perceived however the conditions for it to be perceived in this way are not always
present. When we see the table as rectangular, we are perceiving its normal shape.
But when we are not perceiving the table as rectangular, we are perceiving its
relational properties.
