Direct Realism and Perception

[RussellA]

The logical impossibility of Direct Realism because of the nature of the causal chain from the world to the mind

The Direct Realist (DR) agrees that there is a causal chain between something in the world and our perception of it, but argue that there is a difference between how we see, Phenomenological Direct Realism (PDR) and what we see, Semantic Direct Realism (SDR).

The SDR justifies knowledge about the external world as immediate awareness of the external world, not any immediate awareness of any intermediary between the external world and perception of it in the mind.

The SDR attempts to solve the problems for DR associated with the causal chain from object to perception using disjunctivism (a veridical perception and an illusion or hallucination are different types of mental states), relational properties (even though a square table may look rectangular, the object does not change but its relation to the observer does) and common sense (the problem with IR is its conclusion that the world as we know it does not exist).

The problem for DR with the causal chain is the nature of the connection between effect and cause, between a subsequent link in the causal chain and an immediately prior link in the causal chain.

Hume wrote that we cannot directly observe any necessary logical connection between cause and effect, but can only observe a “constant conjunction” between cause and effect. DR depends on a necessary logical connection between cause and effect in order to directly know the object in the world.

Kant wrote that causality is not something we learn from the world, but is an inherent category within humans that we need in order to be able to understand what we observe. Humans may know without doubt that each effect must have a cause, thereby negating Hume’s problem, but this is not the same as knowing from an effect the cause.

Spinoza wrote that, as a conclusion in mathematics logically follows from its premises, an effect logically follows from its cause. However, this relationship is one-directional, from cause to effect, not from effect to cause.

Within the causal chain, which the DR accepts as real, each effect (each subsequent link in the chain) may have more than one cause (each immediately prior link in the chain).

It logically follows that one perception in the mind may have multiple possible causes in the world. This means that SDR cannot ignore the causal chain as an irrelevant intermediary between the external world and the perception of it in the mind, and therefore must take into account the causal chain in any understanding of our perception of the world .

As soon as the causal chain is taken into account in any theory of perception, where one effect may have multiple possible causes, the position of the DR is shown to be logically inviable, if we are to have any direct knowledge of what is in the external world.

[Corvus]

@RussellA

A reasonable definition of knowledge is justified true belief.

If I am living on Mars, I may believe that there are snooker balls on Earth because I saw the World Snooker Championship from the Crucible Theatre on TV. However, this would not be knowledge unless it was true that the World Snooker Championship was filmed in Sheffield.

True beliefs are justified via your reasoning, hence wherever you are, your beliefs can be justified if you use reasoning.

@RussellA

but would not agree that they are seeing the concept of a table in front of them in the world, as concepts only exist in the mind.

It sounds absurd to deny the real chair and table in front of them, and think that they are only having the concepts of chair and table.

[RussellA]

@Corvus

True beliefs are justified via your reasoning, hence wherever you are, your beliefs can be justified if you use reasoning.

I disagree. The truth exists independently of any beliefs justified using reasoning. We cannot invent the truth by justifying our beliefs using reason.

@Corvus

It sounds absurd to deny the real chair and table in front of them, and think that they are only having the concepts of chair and table.

Spoken like a true Direct Realist.

The problem is that we only know about the world through our five senses. We directly know our sensations from which we can only infer their causes. For example, we may perceive a blue colour, which is direct knowledge, from which we may infer that in the world is a blue table, which is indirect knowledge.

It is logical impossibility to know the cause of a sensation though our senses, in that our perceiving the colour blue may be a hallucination, an illusion, the colour blue, a wavelength of 475nm or something else entirely.

A chair is a concept, and to say that in the world is a real chair is to say that in the world is a real concept. But the concept of a chair encompasses many particular instantiations of the concept, such as something that is grey, something that is brown, something that has three legs, something that has four legs, something made of wood, something made of plastic, etc. However, in the world, what we are seeing is just one particular instantiation of the concept. Concepts such as “table” don’t exist in the world. Particular instantiations of the concept “table” exist in the world.

[Corvus]

@RussellA

I disagree. The truth exists independently of any beliefs justified using reasoning. We cannot invent the truth by justifying our beliefs using reason.

That sounds like a self contradiction on your previous claim that truth is justified true belief.

You cannot deny what you claimed on your last post.

@RussellA

It is logical impossibility to know the cause of a sensation though our senses, in that our perceiving the colour blue may be a hallucination, an illusion, the colour blue, a wavelength of 475nm or something else entirely.

You don’t need to know the cause for chair and table to know the chair and table in front of you. You see them, and you use them.

@RussellA

A chair is a concept, and to say that in the world is a real chair is to say that in the world is a real concept.

A chair is chair, not a concept. Even if you didn’t know the concept of chair, the chair exists.

[Corvus]

@RussellA

Particular instantiations of the concept “table” exist in the world.

A chair exists well before talking about the concept of chair. The concept of chair only comes into existence, when you ask what is chair. Then you will try to think what a chair means, and describe with the definition with all the uses, shapes and properties, different styles etc.

Long before people questioned and described what chair is, they must have used it in daily life without the description of what it is.

Concept is just description on the object the concept refers to.

[RussellA]

@Corvus

That sounds like a self contradiction on your previous claim that truth is justified true belief.

Knowledge is justified true belief

@Corvus

You don’t need to know the cause for chair and table to know the chair and table in front of you. You see them, and you use them.

This is Direct Realism.

[Corvus]

@RussellA

Knowledge is justified true belief

What is truth, knowledge and relation between them?

@RussellA

This is Direct Realism.

which is a sensible view on some of the objects we perceive in the material world. But the abstract objects which we have no physical access to, may exist in our mind.

So, both are true. It just depends on what objects and situations you are talking about. Claiming one is right and the other is wrong sounds incorrect.

[RussellA]

@Corvus

What is truth, knowledge and relation between them?

I believe that chairs exist in the world. I am able to justify my belief because today I sat in one.

If it is true that chairs exist in the world, then I have knowledge about chairs. If it is true that chairs don’t exist in the world, then I don’t have knowledge about chairs.

@Corvus

which is a sensible view on some of the objects we perceive in the material world. But the abstract objects which we have no physical access to, may exist in our mind.

A view sensible to Direct Realists, but not to Indirect Realists.

[Corvus]

@RussellA

I believe that chairs exist in the world. I am able to justify my belief because today I sat in one.

So you are committing yourself to DRist here. But for some strange reason, you seem to stray away from the truth, and entertain yourself thinking and claiming that the concept of chair is what you see and know, not the real chair.

@RussellA

If it is true that chairs exist in the world, then I have knowledge about chairs. If it is true that chairs don’t exist in the world, then I don’t have knowledge about chairs.

Truth and knowledge can be reasoned out by your own thinking. You don’t need anything else many times. You don’t need to do anything to know 1+1=2, and you are “RussellA”, not RussellB. You don’t need to ask anyone in Mars, if the snooker balls exist somewhere in the Earth, because you know that they do (from your own intuition, experience and recollection and common sense)

@RussellA

A view sensible to Direct Realists, but not to Indirect Realists.

Then IR folks seem to be incorrect on their beliefs and ideas.