Three a week: the physical world

Everybody seems to be invested in the physical world. Three questions:

Question 1: Does the physical world exist?

Seems like an easy question to answer. Of course the physical world exists, we interact with it every day. What could be more real than tastable, touchable physicality?

Question 2: What are the reasons for belief in a physical world?

So, if asked the question, “Why do you believe in physical reality?”, one would quickly respond, “Because I can see it, touch it, smell it, and I interact with it all the time.”

Here’s the potential problem with that: It’s pretentious. In fact, all of the above propositions are completely unknowable. Here’s why:

Your physical senses can never know the objective cause of the experiences you have. You might say, “I am feeling a desk right now”, but that is inaccurate. You have the experience of feeling a desk. What was the cause of that experience? You merely assume that your experience of a desk was caused by a physical desk. This does not have to be the case.

Think, for example, about your dreams. Surely your experience of reality in a dream is not caused by corresponding objective physical reality. If you ever have flying-dreams, you know that your experience of flying is not actually due to you flying; it is merely a sensory experience.

So, how can you ever get outside your senses to see whether or not your experience is actually an accurate reflection of physical reality? You can’t. While you might be utterly convinced that the desk you feel actually exists, all of your beliefs rest on your subjective experiences. It might be no different than somebody within a dream insisting they are flying, because they keep having the convincing sensation that they are flying.

Question 3: Should we abandon belief in physical reality?

If we can never know whether or not the physical world actually exists, and, in fact, the only justification for our belief in a physical world is circular, should we get rid of such a belief altogether?

It’s a tough question, but here’s my suggestion: don’t base any fundamental beliefs on the existence of the physical world. You can never have certainty that it exists. Keep your beliefs about the external world practical, and don’t try to conclude anything important about it.

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7 Responses to Three a week: the physical world

  1. Rich Stauter says:

    Trusting our senses as to the “reality” of the outside world is the first step of “faith” humans take. But it is seemingly a necessary step. Because if we can not trust our senses to provide us with accurate information about the world outside of our self-consciousness, what is the point behind all our questions about reality, the truth, the meaning of our existence, etc? It seems that all our questions and yearnings about “reality” become largely unanswerable because we do not possess the faculties to reliably reach outside of our own consciousness and discern reality. We are left with not much more that our own imaginations and resulting self-deceptions (of course we will never no if they are self-deceptions because there is no way to reach outside and test them.

    • Steve says:

      We don’t need to take this leap of faith. You have synonymized “reality” with “reality about the external world”. This is a mistake. I can know plenty of things to be true without making a leap of faith that the external world exists.

      I do agree though, it does not seem possible to know with certainty whether or not an external world exists, but this does not matter. We do not need to worry about such things.

      If we do seek knowledge about physical reality, it is perfectly acceptable to use an “if-then” logical methodology. “If it is the case that X is true about the external world, Y will be true.” We can use this methodology quite effectively, even if all of our arguments hinge something we can not know with certainty.

      This is why I have advocated for not allowing any beliefs about the physical world into the core of one’s worldview. Why base the foundation of your worldview on something which can not be known with certainty, especially when this does not have to be the case?

      • Rich Stauter says:

        But without an external reality, there is no certainty of any reality other than a self-consciousness than can only be sure that it is conscious of itself. Anything else that we might want to call the “real world” may be nothing more than self-deception and self-delusion. What is true for me may not be true for you and so there is no point of even discussing the “reality” of anything. We have lost any hope of a common reference or baseline against which to measure our thought system.
        In other words, for reality to be “real”, it must be external. Otherwise, how do we know it’s not imaginary on our part?

        • Steve says:

          While we may not be able to have certainty about external reality as it relates to our senses (taking a leap of faith does not solve this), we can still know things about it with certainty if it exists.

          Propositions that are necessarily true are true in every possible world, or in every possible existence. This has nothing to do with the scientific method, and is nothing empirical. Necessarily true sentences, which we arrive at through logical reasoning, are true in all possible worlds, whether they “really” exist or not.

          For example, nothing can be red and not red at the same time. This is true in any possible world – hypothetical worlds, different physical universes, hallucinations, you name it. There are lots of necessarily true propositions which we can know with certainty apply to an external world, if it exists.

          Again, this is making use of an “if-then” framework. If it is the case an external world exists, we can know things with certainty about it. This is not a “sensory” methodology, this is a purely rational one.

          • Rich Stauter says:

            It is not at all clear to me that a person would be able to conceptualize any propositions without referencing information provided to us through our senses. For instance, you gave an example of it not being possible for something to be red and not red at the same time. But this references both “something” and its property “red”, concepts that come to us from the outside. It seems that nearly everything that we might make propositions about (with the exception of propositions about our own self-awareness) references our experiences of an external reality. Furthermore, we can talk about the concepts of “all possible worlds” etc., but they invariably reference the world or existence that we actually “seem” to experience. Please comment on why this is not a problem.

            Also, as an example, does it matter that you can’t be sure that your wife (or any other person that is important to you) actually exists, that all you can be certain of is that you have the experience that she exists. After all, she might merely be a figment of your imagination that you have sub-consciously designed to provide you with pleasure. Please comment.

  2. Rich Stauter says:

    Please be aware that when I use the word faith, I do not mean the blind leap of helplessness that many people take faith to mean. Rather, I believe that the faith to believe in the outside world based on your experiences comes about as a rational and reasonable process.

  3. Steve says:

    When I reference “red”, I can not know whether or not I am referring to is the same thing you are. But this is irrelevant. What matters is that you, to yourself, have a concept a red (regardless of that is the concept of red that other people have), and the laws of logic apply to it.

    I agree, we can not have perfectly precise communication between humans if the external world is not known. But this is just a fact about reality. Just because we might not be talking about the same thing, doesn’t mean that we can’t know truth. Regardless of if I am hallucinating, or if I am the only conscious being in existence, nothing can be red and not red at the same time. It does not matter if I am referring to a “red car on planet earth” or a “red Zignock in alternate dimension Q”.

    And yes, because it is seems likely that an external world exists, our concepts do refer to what we think of as the “real” world. But again, they don’t have to. I have never had any sensory experience of martians who regurgitate hot-pockets, but I can know things about them, if they exist.

    And indeed, I can not know that my wife exists. I can know that it impossible for anything to be green and not green at the same time, and that applies to my wife, whether or not she objectively exists. Now, as far as I know, she does exist, and I will act according to my sensory beliefs about her. However, I will not make my fundamental worldview wrapped up in whether or not she exists in “physical reality”. Again, practically speaking, I will live as if she does, but I can not deceive myself into thinking I know she exists.

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