Are you directly perceiving reality?

Category : Appearance, Reality and Illusions.

Why investigate this topic?

The majority of us take for granted the reality around us, I too am guilty of this – assuming that I see, experience and perceive genuine reality.

Every so often I do hear of sceptical claims which attempt to question the very basis of our reality. Such examples have been portrayed through the likes of The Matrix, Common topics such as “how do you know you are not dreaming?” come to mind.

Predominantly, the “Appearance, Reality and Illusions” segment of the apeiron blog will discuss these controversial questions… but in this article, I want to delve into the question of how we can be certain that we perceive the universe directly.

By perception, I am referring to all interaction that you have with the external world through your senses; be that touch, smell, sight or hearing.

Direct, or Naive Realism.

Generally speaking, those who have not thought to question this topic before will be considered direct realists. They are naive because they assume, without rational investigation, that they are percieving the universe directly and that what they say see, feel and touch is reality.

For example, when they percieve a table – they assume that what they are seeing is the true nature of the object that happens to be in front of them. This is believed to be a mind – independent object, meaning it exists regardless of whether someone is perceiving it or not.

So, if you are reading this and have taken perception for granted, without questioning what exactly it is you are perceiving then you are a direct realist.

Why should we question direct realism?

The argument from illusions and hallucinations against direct realism.

One of the most reputable challenges against the proposal from direct realism appeals to experiences of hallucinations and illusions. For simplicity, an illusion occurs when you perceive something that exists – but you perceive it to have qualities that it does not. By example, me perceiving a coffee cup in my perceptual field as red, when in fact it is blue.

Alternatively, a hallucination occurs when you perceive something which bears properties, when in fact this thing does not exist within your perceptual field. By example, me perceiving a red coffee cup in front of me when in fact there is nothing in front of me.

Both hallucinations and illusions pose a threat to the belief that we perceive directly. Because if we viewed the universe directly then we would always experience veridical perception (the universe would be perceived exactly as it exists, and hallucinations and illusions would not exist.)

The arguments from hallucination and illusion are as follows :
P1. In cases of hallucination or illusion, we are perceiving something that does not in fact exist.

P2. We must be perceiving something that bears these properties.

P3. This thing cannot be the physical object, as we have already concluded that the object either does not exist, or bears different properties. Instead, it must be something mental – be that a mental image or mental representation.

P4. Hallucinations and genuine perception are indistinguishable from the viewpoint of the perceiver, so both should be treated the same.

P5. So, in cases of perception – be that genuine or hallucination, we are percieving a mental image or representation rather than a mind-independent entity.

Premise 1 through 3 seem straightforward : all we are stating is that if we hallucinate we cannot be perceiving reality so must be perceiving something else. This adopts the phenomenological principle – meaning if we perceive something, we experience that something, and so that thing must exist. 

But premises 4 and 5 appear a little more complex and adopt a few assumptions.

Premise 4, adopts the common kind principle; which means that a mental event that takes place during genuine (veridical) perception can also take place when one is not veridically percieving.

This principle implies that genuine perception, and hallucinations are fundamentally of the same kind. This means, how perception occurs for the one also applies for the other.

Because of this, as discussed in premise 3 – as in cases of hallucination and illusions, we must perceive indirectly  in virtue of seeing a mental image : this must also be the case for true, or genuine perception.

So, following this thinking – direct realism is false and we do not perceive the world directly.

This challenge also implies that what you are perceiving is mind-dependent (reliant on your mind, given you are perceiving a mental image rather than the physical object.)

This has also led to alternative thinking featured in idealism, which states that ALL perception is nothing more than an idea, or a mental image.. and no physical, mind-independent objects exist. (I will not be discussing this in this article but would recommend delving deeper yourself.)

Instead, arguments from illusion/hallucination typically act as support for indirect realism which involves perceiving objects indirectly, but these objects still exist independent of mind (we merely perceive a mental image that represents this physical object. This representation is mind-dependent, and does not exist without us.)

Indirect Realism or Sense Datum Theory

Due to the criticism mentioned above, it appears that a more rational proposal of perception is Indirect realism. This means that you perceive reality in virtue of seeing something else. This something else is often known as sense datum, or a mental image.

Sense datum, generally refers to the things that are made available to us during perception : they possess the properties that we take the object in the real world to have. Sense datum theory states that we perceive mind-dependent objects directly, meaning that we see the physical object indirectly.

Sense datum usually refers to a mental image. So, by example when you perceive a table – you will directly perceive a mental image or sense datum which represents the physical table… but you will only perceive the table indirectly.

When considering the instances of illusion and hallucination, this appears a more satisfactory, if not correct explanation of perception in comparison to the naive view. As it can explain both through the claim that you are perceiving sense data, rather than the physical object – and this how perceptual error can occur.

This is just one of numerous indirect realist theories; this one is relational meaning are perception is a relation between ourselves, a mental image and the physical object.

Other theories include adverbialism which states that perception is non-relational, and instead you are merely undergoing a way of perceiving. For example, when you perceive the colour red –  this relates to nothing (be that a mental image, or physical object,) instead you have simply undergone the, lets say, technique of perceiving red. This “technique” is comparable to undergoing something like walking… this is too is non-relational and exists independent of any other thing.

(I have explained this proposal briefly, and it is worth researching adverbialism yourself if you seek a deeper understanding. It is also subject to a handful of challenges.)

Nonetheless, whether indirect realism is in fact true is still widely disputed and some direct realists have defended their viewpoint through responses such as disjunctivism.  


The main message of this article is that :

  • Counter to popular thinking, there exist numerous arguments which indicate that we do not percieve the world directly. As a result, we are wrong to naively adopt direct realism without rational analysis and discussion.
  • Despite convincing arguments found in indirect realism, Philosophers are yet to reach a conclusive explanation of how we perceive the world.

What do you think? Are you an direct realist or indirect realist?

Are you more radical? Do you think nothing exists in this universe other than our own mind and ideas?  (Idealism? Cogito Ergo Sum?)

Thank you for taking the time to engage with me,

Feel free to leave the answers to my questions below in the “comments section,” or tweet me : @theapeironblog

Jon Hawkins.

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