Is indirect realism a plausible theory of perception?

Adam Dance

I am going to look at the various positions available when asking, how do we perceive the world? I plan on looking at Locke’s position and the reasons why he asserts that particular theory. I will also discuss the problems with Locke’s theory and the possible responses to them.

John Locke is an English empiricist hence he believes that all our knowledge and ideas are based on experience. In his essay he asserts that there are no innate ideas. He believes the mind to be like a blank page or tabula rasa. He says that sensation and reflection are all that is needed to form all of our ideas. From this empirical base Locke begins to build up a representational theory of perception. Locke’s chosen theory of perception is known as indirect realism. This theory says that we are not directly acquainted with the material world. It says that we have a direct acquaintance with a mental idea of the world. These ideas indirectly represent to us the material world. The position does accept that the material world exists independently of us however we are not in a position to know it directly. There are two types of indirect realism that exist. One is scientific indirect realism and the other is naïve realism. Scientific realism is the position that properties like colours are ideas that are not directly representing reality, they are somewhat dependant on the observer. Naïve indirect realism asserts that even the idea of colour does actually correspond to actual colour in the world.

There are some problems that the indirect realist faces. Firstly there is the resemblance problem. We see external objects by virtue of seeing the internal representation of the object, which is supposed to resemble the object. The problem is that the idea cannot resemble the object because the object is spatial where as the idea is non-spatial. The indirect realist may reply by saying even if they don’t resemble each other it is true that the object causes the idea but is causation enough? Shadows are caused by objects but in seeing the shadow we cannot say that we see the object. I do not believe that this is a particularly damaging argument. The idea does resemble the object even if it is not spatial. We say that a photograph resembles the actual scene it is depicting even though the photograph is two-dimensional and the actual scene is three-dimensional.

Secondly we have the regress problem. If indirect realism explains perceiving an external object by perceiving a mental idea of the object then how does it explain how we perceive the mental image? It is argued that a regress is inescapable because perceiving the idea must be explained in the same way as perceiving the object, i.e. perceiving an idea of the idea. However this problem seems easily escapable if we simply assert that we do have direct acquaintance with mental ideas although not with the actual external objects. This could be explained by saying that we cannot directly perceive ...

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There is another argument against indirect realism, which says that if a subject perceives an idea, then they are in genuine relation to the idea. If that is the case then it is argued that the idea and the subject are logically independent. In which case it sounds ridiculous to say that ideas of objects can exist independently. However I do not put much weight on this argument. It seems clear that the idea and subject are not logically independent. I am in genuine relation with my shadow however I would not assert that my shadow is therefore logically independent of me. Mental ideas are caused by subjects interacting with external objects which then produces the idea, the only logical independence here is that between the subject and the external object.

The veil problem is often seen as a serious objection to a representational theory of perception however I do not believe it to be so. The veil problem says that we see only mental images and not the real world, therefore these ideas form a veil between us and reality causing us to be unable to ever experience reality directly. The objection is that this leads to scepticism about the external world. It seems to me that the whole point of indirect realism is that it does produce scepticism. Mitigated scepticism is a useful tool for searching for the truth. The point of the theory is to avoid the naivety of naïve, direct realism. Also I don’t think it does lead to scepticism about the external world. The theory does not question the existence of external objects, only our ability to know them. It seems that there has been an ontological and epistemological confusion here.

I would now like to consider some of the alternatives to Locke’s view. Locke’s position is a realist position and there are other realist positions such as direct realism. Direct realism says that the real world does exist independently of us, as with all realist theories, and we directly perceive external objects themselves. The theory does overcome the regress problem and the resemblance problem but it does have problems of its own. The argument from illusion is as follows: There are times when through illness or drugs we see false images, hallucinations. In these cases we must be seeing something however there are no objects with which the hallucinations correlate. Therefore we must be seeing merely a mental idea as with indirect realism. The argument concludes by saying that if we only see ideas during hallucinations then we must only see ideas at all other times. The problem with this is that the only time we do see hallucinations is when something is going wrong with the brain which causes us to see false images. Just because when the brain is malfunctioning we see false images does not imply that we are only ever acquainted with mental ideas of objects. It simply implies that when ill or under the effect of drugs the brain generates illusions. Also in the case of a bent stick in water we are not seeing a false mental image, it is a physical illusion. This means that the illusion has already occurred before the light has entered our eyes. Again this does not show that we must always see ideas and not the real world. The stick bent in water is simply a case of when the world becomes distorted due to perfectly normal physical processes.

The brain-in-vat argument against direct realism is a strong argument. The argument is as follows: Assume that you are perceiving something; consider then that there is a brain-in-vat version of you which is in exactly the same brain state as you; both have the same visual ideas. The brain-in-vat you is having the visual impression but is not receiving the sense data through eyes because it is just a brain. This indicates that it is the functional brain state that causes the idea of whatever the visual image is. Therefore when we see something our brains are in a certain state that causes an idea of the external object by virtue of which we see the object. This seems to be a sound argument. I believe the best place to attack it is by questioning the whole scenario. Is it logically possible for two brains to have the same token of idea at the same time? It could be said that the brains are different enough, even if it is merely a locational difference, so that the same token of idea is not possible. Also the randomness of cells and molecules in the brain would make creating an exact replica impossible. Heisenberg’s uncertainty principle says that you cannot observe the location and momentum of a particle at the same time, therefore creating brain-in-vat you is implausible.

A further argument against direct realism is the time lag argument. This says that perception takes time. If we are looking at a distant star the sense data we are receiving could be misleading because the star could have died. Light can take years to reach us from distant stars so how can we directly perceive something which may not even be there. I believe the direct realist could reply to this by saying that we are directly perceiving rays of light which we accept may be so old that we are being mislead. Having conceded this I don’t think it is a major blow for the theory.

Both the realist theories that I have discussed come in two different forms. We have naïve realism and scientific realism. Naïve realism is the view that everything we see represents reality perfectly. Even properties like colour, which by many are thought to be subjective, are said to represent the actual colour of the external world. Scientific realism is slightly more conservative by saying that properties like colours may be affected by the observer and so may not appear as they do in reality.

Phenomenalism is another major theory of perception and is a theory with many subdivisions. Phenomenalism says that the immediate object of perception is a subjective idea. The theory is anti-realist, that is to say that it does not believe that there is a fixed reality out there. Phenomenalism claims that all we perceive are ideas and appearances and material objects only exist in the mind of the perceiver as a construct made up of bundles of experiences. There are no facts independent of the observer. The two main types of phenomenalism are reductionism and eliminativism. Reductionism asserts that material objects are nothing but percepts, they are reduced down to certain orderings of experiences. Reductionism breaks down into a further two parts, idealism and classical phenomenalism. Idealism says that material objects cease to be when they are not being perceived, they are only percepts and so if you take away the perceiver you take away the object. Classical phenomenalism says that objects are possibilities. To say my car is outside is merely to say that if I was in the correct situation I would have car percepts. Eliminativism, on the other hand, says that talk of material objects is meaningless because it is an empty concept. The term “material objects” depicts nothing in reality, all that exists are subjective states.

If we take classical phenomenalism to be the standard view we must ask the question if objects are just possibilities then why do so many people agree on what objects “exist”? For example if to say there is a tree outside means that in the correct situation I will receive tree percepts, we must ask why will we receive these percepts? And more importantly why is it that many people have the same percepts of the same object? When thinking about what is causing these percepts surely the obvious response is to say that there is something actually in reality causing the percepts. However it seems that the phenomenalist appeals to some sort of global coincidence that we all perceive the same things in the same situation. The theory does not seem to offer any real reason for endorsing the theory or any arguments for why it should be seen as the correct theory of perception. I believe the theory to be so counter intuitive it cannot be considered a valid theory.

In conclusion it looks like the realist theories are far more convincing than phenomenalism. Locke’s position does seem quite a sound position. There are arguments against his indirect realism however all have counter arguments. Having investigated all the theories I would personally endorse scientific indirect realism. I therefore conclude that indirect realism is a valid theory of perception and probably the one with the most verisimilitude.