• NOS4A2
    7.5k


    In your first post you’ve already explained quite well where you think the issue lies, and I’m satisfied by your definitions of direct and indirect realism: “It’s about whether the properties of whatever we're going to call the perception are given by the external world (directly), or via the internal world (indirectly)”.

    The only difference between us here, I think, is when I write of perception I do not include the “actions toward it (speech, interaction, etc)”, “reciprocal action”, like conversing about trees, which are no doubt “given” by “the internal world”. These to me are not acts of perception, though I suppose that’s debatable. I am only speaking of raw, sensory experience, acts such as seeing, hearing, smelling, and so on.

    I do not dismiss that “anything happening inside the body as not the object of [my] questions”, but I deny that anything happening in the body is the direct object of perception, “the perceived”. Rather, these are the actions of the body, “the perciever”.

    Anyways, I hope that clarifies.
  • Joshs
    4.7k


    I deny that anything happening in the body is the direct object of perception, “the perceived”. Rather, these are the actions of the body, “the perciever”.NOS4A2

    Hallucinogenic chemicals modify the appearance of perceived objects in many ways; in terms of size, shape, color and degrees of movement or rest. They dont have this effect at the level of the sensory receptors but at deeper levels of processing in the brain. Manipulations of the receptors can decrease the amount of data received by the brain ( blurring, loss of peripheral vision, color-blindness, etc) but not qualitatively distort objects the way hallucinogens can. i suspect that the longer one remains under the effect of a hallucinogen , the greater the likelihood that one’s visual system begins to ‘correct’ the distortions.

    I say this because research subjects who wear glasses which turn their visual field upside are able to see the visual field normally again while using the glasses for a certain period of time. The distortion of the visual field by the glasses takes place at the level of the receptors but the correction by the subject’s perceptual system takes place at a deeper level of processing. If these deeper levels of processing have such power over what objects we see and how we see them, don’t this suggest that perception is a model we construct of the world and test against it, rather than a direct reception of data?
  • NOS4A2
    7.5k


    My issue is that these models are nowhere to be found, so I am unable to say anything of the sort is constructed, at least until such models can be instantiated. The representational theory of perception, that we are constructing models of reality and viewing them, implies that something is viewing the representation—but again, this viewer needs to be instantiated. This is why I ask the indirect realist to reify this model and reify this little viewer so we that we can better understand their natures. What are these models? Who is viewing these models? Who perceives what?

    Until then I would prefer to say that the perceiver is modified, for instance by ingesting hallucinogens. He sees things differently than he usually would because he himself is different than he usually would be. I think this approach would better describe the difference in character of phenomenological experience between veridical experience on the one hand, and illusions and hallucinations on the other. In other words, if we describe how the perceiver and not the perceived are different, we’ll come to a better understanding of illusion and hallucination in general.
  • RussellA
    1.1k
    Direct Realism is not valid, as it requires, just from knowledge of an effect, direct knowledge of its cause, which is impossible.

    Direct realism argues we perceive the world directly.

    A possible sequence is: sunlight travels from the sun to a tree and hits its leaves. Wavelengths between 415 and 740 nm are absorbed by the Chlorophyll in the leaves, and wavelengths between 520 and 625 nm are reflected off the leaves towards our eyes. Say a wavelength of 550 nm enters my eye. In my sense data is a patch of green, I perceive that I am looking at a green tree, and my cognition tells me to go towards it as there may be edible fruit on it.

    Both the Indirect and Direct Realist would agree that we directly sense the colour green. However, it is impossible to directly know just from an effect the cause of that effect, although it may be possible to discover its cause indirectly. Therefore, it is impossible to directly know just from sensing the colour green its cause, although it may be possible to discover 550 nm as its cause indirectly.

    For example, if a stationary 1kg object starts to move at 10 ms after being hit by another object, we know from the conservation of momentum that the mass * velocity of the hitting object was 10 kg m/s. However, there are an infinite number of possible combinations of m and v of the hitting object. This means that, even if we did know the mass and velocity of the object that was hit, we cannot directly know just from the behaviour of the hit object the m and v of the hitting object, although it may be possible to discover this information indirectly.

    Therefore:
    1) Just by knowing an effect, it is impossible to directly know its cause. Just from sensing the colour green, it is impossible to directly know that it was caused by a wavelength of 550 nm, although it may be possible to discover this information indirectly.
    2) Similarly, it is impossible to directly know that the 550 nm was caused by a green tree.
    3) Therefore, Direct Realism, which argues that from just knowing an effect we are directly able to know its cause, which is impossible, is not a valid position to take.
  • NOS4A2
    7.5k


    The direct and indirect realist differ in respect to what they directly perceive. For the direct realist, we directly perceive all that’s in our periphery. For the indirect realist, we directly perceive some kind of sense data. So I doubt they would both agree that they directly sense the color green.

    I’m not sure a direct realist position entails the argument that just by knowing an effect we are directly able to know its cause. Would you explain?
  • RussellA
    1.1k
    I’m not sure a direct realist position entails the argument that just by knowing an effect we are directly able to know its cause. Would you explain?NOS4A2

    Direct Realism requires backwards causation, which is impossible

    There is a direction to causation, in that it is not the case that first there is an effect and later there is a cause. For example, first sunlight hits the leaves of a tree, then light travels from the leaf to our eyes which we can then sense as green. It is obviously not the case that we sense green, then light travels backwards from our eye to the leaf. There is a direction of causation as there is an arrow of time.

    Causation also requires that there is a direction in which information flows. For example, I know that if I throw a stone at a window there will most likely be one possible effect, the glass will shatter. But if I see a shattered window, I cannot know which of several possible causes was the actual cause, a thrown stone, a broken branch or a flying bird. For the same reason, in just sensing the colour green, I cannot directly know its cause because of the fundamental direction of causation, and the direction of information flow within causation.

    But on the other hand, when I sense the colour green I psychologically know beyond doubt that I am looking at a single event, a green tree. So how to explain this seeming paradox, that information has appeared to flow backwards through time, in that, given a single effect, my sensing green, I believe I know a single cause, a green tree, something that is impossible given the arrow of causation.

    Direct Realism's solution to this seeming paradox is by equating the effect with the cause, in that, if the effect is sensing of the colour green, Direct Realism says that the cause is also the colour green. Given a single effect, Direct Realism gives a single cause that is identical with the effect. However, this is an illusion.

    One of the arguments against Direct Realism is the problem of illusion, in that a stick half in water appears bent. However, this is a different kind of illusion to that of Direct Realism, the psychological illusion that the cause of an effect is identical with the effect, that when we sense the colour green its cause was also the colour green. Direct Realism is a psychological illusion, where the mind a priori believes that an effect, a sensation in the mind, such as sensing the colour green, is also the cause of that sensation, ie, seeing a green tree.

    This is also a different argument to the argument that there can often be a long and complex causal sequence between an object and event and the perceiver. Many Direct Realists accept this fact, and still maintain that external physical objects or events can be immediate or direct objects of perception, which is a reasonable position. My argument is that Direct Realism is an illusion because it does not take into account the fundamental restrictions in the direction of information flow. There is an asymmetry in the direction of causation, in that causal indirectness inevitably results in cognitive indirectness.

    The "arrow of time" linking causal interconnections is one aspect of Leibniz's Principle of Sufficient Reason, one of the four laws of thought, which states that everything must have a reason or a cause. Our normal understanding of causation is that we can only causally affect the future but not the past. In all cases of causation, the cause and the effect are placed in time such that the cause precedes its effect temporally, to such a degree that we intuitively have great difficulty imagining things otherwise. Whereas David Hume argued that causes are inferred from non-causal observations, Immanuel Kant claimed that people have innate assumptions about causes, and about the temporal ordering of events and "directionality" of time

    In our example of sensing the colour green and seeing a green tree, Direct Realism is the position that the green tree is a necessary cause of sensing green, whereas Indirect Realism is the position that the green tree is only one sufficient cause of sensing green.

    Direct Realism is an illusion because it equates the cause of an effect with the effect, in that it equates sensing the colour green with its cause, a green tree, which is impossible, as it would require backwards causation.
  • NOS4A2
    7.5k



    From my own standpoint, the necessary and sufficient cause of human perception is the human perceiver, and I would hold that the human perceiver is the beginning of every causal chain regarding human perception, including seeing green trees. Perhaps one can formulate a better causal chain from this starting point, whether green trees are sufficient/necessary conditions to seeing green trees, and so on. But the cause will no doubt precede any subsequent effect in your arrow of time.

    But for now, “from whom, and upon what, is this activity directed?” is my central question to the indirect realist.

    Suppose that if the perceiver is not perceiving something directly he is perceiving nothing. There must be something upon which the activity is directed.

    For direct realism, the perceiver directly perceives the world, and thus we are able to distinguish between the perceiver and the things upon which he is directing this activity.

    For the indirect realist, the perceiver directly perceives sense data, ideas, impressions, representations, models, sensations—internal flora and fauna indistinguishable from the perceiver himself—leaving us no distinction between perceiver and perceived. So it’s like saying we perceive perceptions, we see seeings, or we feel feelings.

    In order to answer the question of what we are directly perceiving, one must posit something that is not the perceiver to find it. Since indirect realism is unable to do so, indirect realism is redundant.
  • Richard B
    334
    There is a direction to causation, in that it is not the case that first there is an effect and later there is a cause. For example, first sunlight hits the leaves of a tree, then light travels from the leaf to our eyes which we can then sense as green. It is obviously not the case that we sense green, then light travels backwards from our eye to the leaf. There is a direction of causation as there is an arrow of time.RussellA

    Let’s clarify something here. What caused us to detected the green coming from the leaves of the tree. Well scientific theory teaches us that chlorophyll gives plants their green color because it does not absorb the green wavelengths of white light. This is a cause. In your example you are asking what causes a human being to sense green in reflected light. This cause is happening in the eye and brain. This cause occurs in the brain and is after the light striking the leaf.

    But how does it follow that we do not perceive the external world as it really is. The leaf is green because it does not absorb the green wavelength. If it is not, what color is it? If you say there is no color, well OK feel free to define “what it really is” any way you like, maybe it will have some interesting utility for us.
  • Tom Storm
    7.3k
    Is it not the case that humans experience specific light waves as color? Color is not a property in the world so much as a constructed perception, based on our visual apparatus.
  • Richard B
    334
    Let us assume we humans evolved to where detecting “green” was so important in that it gave us the necessary energy to live every day. Every time we come across an object that is “green”, we gather it for nourishment by just looking at it. Since it was so important, we developed machines, more sensitive and accurate than humans, that could detect the green color of objects. So light would come in and the machine would report and answer “green”. Is the machine having a sensation or constructed perception of “green” to detect the color of “green” in order to report “green”? Like Wittgenstein’s “beetle in the box”, what is in the box has no place in the language game at all; not even as a something for the box might even be empty (like my machine example?).
  • Tom Storm
    7.3k
    I think the beetle/box language game thing can be parked, but I guess you are saying that although humans 'create' green - it is not out there in reality - what is out there in reality is a particular light frequency that we experience as green. This can be objectively tabulated as a quality of the external world.
  • Wayfarer
    18.9k
    One point about the evolutionary rationale for judgement is that the vast majority of creatures, other than h.sapiens, get along perfectly well in their environmental niche without any requirement for conceptual analysis. Furthermore the evolutionary rationale for such faculties as judgement are reductionist, insofar as they propose that reason itself is dependent upon adaptation, which undercuts the sovereignity of reason.

    Unless it is coupled with an independent basis for con fidence in reason, the evolutionary hypothesis is threatening rather than reassuring. It is consistent with continued confidence only if it amounts to the hypothesis that evolution has led to the existence of creatures, namely us, with a capacity for reasoning in whose validity we can have much stronger confidence than would be warranted merely from its having come into existence in that way. I have to be able to believe that the evolutionary explanation is consistent with the proposition that I follow the rules of logic because they are correct-not merely because I am biologically programmed to do so. But to believe that, I have to be justified independently in believing that they are correct. And this cannot be merely on the basis of my contingent psychol ogical disposition, together with the hypothesis that it is the product of natural selection. I can have no justification for trusting a reasoning capacity I have as a consequence of natural selection, unless I am justified in trusting it simply in itself believing what it tells me, in virtue of the content of the arguments it delivers. — Thomas Nagel, Evolutionary Naturalism and the Fear of Religion
  • schopenhauer1
    8.9k

    I think these debates ultimately come down to "what" physical properties are without an observer. What does it mean that charge, mass, energy is "objective"? What is a universe without any point of view? People insert themselves into the picture.. Often when we think of "a universe devoid of a point of view" we think of empty space, or images of planets with nothing else, or something like that. But that's not it either. "Events happening" with no epistemological element, is something we cannot compute.

    I'll pose it to the forum, what are "objective properties"? What does that even mean in any coherent way without measurement, interpreters? Whence is the platform for these events? Are we saying space and time are the interpreters, epistemological frame of the events "objectively"?

    @Joshs @RussellA @Tom Storm
  • NOS4A2
    7.5k


    I suspect an “objective property” is one that is public, available for anyone to measure. With this one needn’t eliminate an observer.
  • schopenhauer1
    8.9k
    I suspect an “objective property” is one that is public, available for anyone to measure. With this one needn’t eliminate an observer.NOS4A2

    What does "available" even mean in that context? "What" are these "things" availing themselves?
  • NOS4A2
    7.5k


    It means that anyone can observe the same properties if they were so inclined. These things would be the objects and systems we measure. Properties describe these things.
  • Tom Storm
    7.3k
    Nicely summarized. :up: I avoid strong metaphysical commitments by claiming a form of pragmatism. I don't need to know what or why just how. No matter what we belief about the nature of reality and being, as soon as we walk out the door we behave as naïve realists. At some level the games we can play with conceptual framing and language don't matter all that much.

    the vast majority of creatures, other than h.sapiens, get along perfectly well in their environmental niche without any requirement for conceptual analysis.Wayfarer

    I think this also holds for the Young Liberals I have known.
  • schopenhauer1
    8.9k
    It means that anyone can observe the same properties if they were so inclined. These things would be the objects and systems we measure. Properties describe these things.NOS4A2

    Again, these are all category errors in the context I described:

    What is a universe without any point of view? People insert themselves into the picture.. Often when we think of "a universe devoid of a point of view" we think of empty space, or images of planets with nothing else, or something like that. But that's not it either. "Events happening" with no epistemological element, is something we cannot compute.schopenhauer1

    You are doing what I was saying we tend to do- inserting ourselves in the picture. You are coming at it from a post-facto manner.
  • schopenhauer1
    8.9k
    I avoid strong metaphysical commitments by claiming a form of pragmatism. I don't need to know what or why just how. No matter what we belief about the nature of reality and being, as soon as we walk out the door we behave as naïve realists. At some level the games we can play with conceptual framing and language don't matter all that much.Tom Storm

    Sure, fair enough. But the question being asked here requires metaphysical positing, maybe not commitments, so that is what I am doing. Obviously, if you asked me about baking an apple pie, observing a tree sway in the wind, and the like, that would be different questions I would be asking :smile:.
  • Tom Storm
    7.3k
    You are doing what I was saying we tend to do- inserting ourselves in the picture. You are coming at it from a post-facto manner.schopenhauer1

    I agree with you. Can we even talk about this subject without being hopelessly enmeshed in strictures of experience and our conceptual schemas?

    Even language is a kind of sense that does not make actual contact with the things it is describing. Language's connection to reality seems as tenuous as that of visual perception.
  • Wayfarer
    18.9k
    I think this also holds for the Young Liberals I have known.Tom Storm

    goes for a lot of folks, don't make it right ;-)
  • NOS4A2
    7.5k


    Why would I leave ourselves out of the picture?
  • schopenhauer1
    8.9k
    I agree with you. Can we even talk about this subject without being hopelessly enmeshed in strictures of experience and our conceptual schemas?

    Even language is a kind of sense that does not make actual contact with the things it is describing. Language's connection to reality seems as tenuous as that of visual perception.
    Tom Storm

    It's philosophy, and inherently messy subjects, so I say go for it. If you want to remain silent on any speculative thing, than do so, but I see us missing out without some speculative hypothesizing. I had a whole thread on this.

    https://thephilosophyforum.com/discussion/13996/have-we-modern-culture-lost-the-art-of-speculation/p1
  • schopenhauer1
    8.9k
    Why would I leave ourselves out of the picture?NOS4A2

    Because I think this will better elucidate your idea about direct realism.
  • Tom Storm
    7.3k
    t's philosophy, and inherently messy subjects, so I say go for it.schopenhauer1

    You misunderstand me. I am asking how it is possible for us to build a robust case (the least 'messy' case possible) in this space. I am not saying that it shouldn't be done.
  • NOS4A2
    7.5k


    The perceiver is required in order to formulate any theory of perception. If I leave it out there is no perception. I only which to understand from indirect realism the point at which the perceiver ends and the perceived begins, and whether something lies between them.
  • schopenhauer1
    8.9k
    The perceiver is required in order to formulate any theory of perception. If I leave it out there is no perception. I only which to understand from indirect realism the point at which the perceiver ends and the perceived begins, and whether something lies between them.NOS4A2

    Well, that's why you need to understand that question. Direct realism seems to me, to posit that we "objectively" see the thing "as it is in itself". What is something "in itself" though? A tree is the tree you see as a perceiver when there is no perceiver? Mind you, I'm not saying the tree doesn't exist without a perceiver. If you answer, "Well, no the tree isn't what an average human 'sees' when observing a tree", you have your answer- and it doesn't indicate direct realism. Sense data, goes through other layers of the brain, and creates something we have called a tree. Even if you (oddly) posited just "sense data" and no other layers involved (whatever that might mean), then there is still something there as a barrier to what is the tree in itself. It is its own "indirect".
  • NOS4A2
    7.5k


    I wouldn’t posit any noumenon, personally. And I reject the view that sense data creates a tree because neither the perceiver nor the perceived can be instantiated, subjectively or objectively.

    Direct realism is simply that we are seeing a tree. This need not entail that we apprehend all properties of the tree just by looking at it.
  • schopenhauer1
    8.9k
    Direct realism is simply that we are seeing a tree.NOS4A2

    Who is arguing against this? So a tree exists, and we are seeing a tree. But that is not really the direct realism argument. Rather, it is positing whether we are seeing the tree in some non-representational way, that is to say, "as it is in its reality". I refer you back again to my previous posts.
  • NOS4A2
    7.5k


    Yes, we’re not viewing a representation of the tree. We need not include the “thing in itself”, which considers the tree independent of any perception of it. I refer you back to my previous posts.
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