Objections to Direct Realism

The problem of illusion

• When viewing a straight stick half-submerged in water, you are directly aware of something that appears bent
• Nothing is actually bent in this situation, however
• Therefore, in this situation, you are aware of something non-physical - sense data
• What you are aware of here is the same kind of thing you are aware of in a normal, non illusory perception
• Therefore in normal perception, you are aware of something non physical

Direct Realist response

• When perceiving a stick in water you perceive something that appears to be bent when nothing actually is
• This can be explained by saying the stick has the property of appearing bent in certain contexts. This property is "relational" as it only appears in relation to you seeing the stick in the water
• Therefore we don't need to put forward a separate mental object (sense data) which is bent, you still see the physical object directly

Perceptual variation - Russel's Table

• When perceiving the table what you're aware of differs depending on the light and angle from which you view it. It could be that someone else observing the same object from a different position sees a different colour or shape. For example a colourblind person may see a table as red but you may see it as green. The table doesn't physically change in the situation
• Therefore, in this situation, you are directly aware of something non physical and what you are aware of is the same kind of thing you're aware of in a normal, non-illusory perception
• Therefore, in normal perception, you are aware of non-physical things

Direct Realist response

• Strawson argue that there is a variation in the way objects look so how we see things depends on context, and we can establish which context is most common and therefore most useful to us.
• Therefore we don't need to put forward a separate mental object - sense data - which is bent, we still see the physical object directly

The problem of hallucination

• When hallucinating, you may see pink elephants dancing on the ceiling when no relevant physical thing is pink or dancing on the ceiling in this situation
• Therefore, in this situation, you are directly aware of something non-physical (sense data) which is the same kind of thing you are aware of in normal, non illusory perceptions
• Therefore, you are aware of non physical things in normal perceptions
• Further, if hallucinations are indistinguishable from normal perceptions, it is possible we are hallucinating all the time

Direct Realist response

• We recognize hallucinations as distinct from true perceptions showing we must know reality directly some of the time or there would be no distinction. In the same way you couldn't say "If my £5 note is a forgery, then maybe all £5 notes are forgeries" as there has to be a real one to copy
• Furthermore, they could argue that all hallucinations are not in fact perceptions, as perceptions are where you have a sensory experience caused by a physical object and there is no physical object causing the hallucination

The problem of time lags

• When perceiving a star in the sky you are aware of something that may have ceased to exist hundreds of years ago, or if you look up at the sun you are in fact perceiving light that has taken 8 minutes to reach your eyes
• the sun may not be the way you perceive it due to time lag
• Therefore in this situation you are aware of a non physical object which is the same as in a normal, non illusory perception
• Therefore you are aware of non physical things in this situation

Direct Realist response

• In these cases what you are aware of isn't a mental object but the state of how the objects were in the past. For example when perceiving the sun, you are directly of how the sun was 8 minutes ago due to time delay instead of your mental image of the sun.
• Therefore, there is no need to put forward a separate mental object as we still se the object directly