• TheMadFool
    13.8k
    Physicalism is the philosophy that everything is physical and by physical, physicalists (those who subscribe to physicalism) refer to matter, energy, and the laws that govern their interaction.

    That out of the way, I want to make a mention of perceptibility defined as "capable of being perceived by the senses and their extensions, scientific instruments".

    There seems to be deep connection between perceptibility and physicalism. For instance, all that we know to be physical are perceptible in one way or another. In fact, the two seem to be synonymous with each other for the perceivable are classified as physical. In short, to be perceivable is to be physical and vice versa i.e. physical = perceivable or to be physical implies and is implied by to be perceivable or physical <-> perceivable.

    To be physical -> To be perceivable is almost too obvious to require stating; after all matter, energy, the laws that govern them, all, are perceivable.

    However, saying To be perceivable -> To be physical is also true means is to define the physical as perceivable i.e. To be perceivable <-> To be physical implies To be perceivable = To be physical.

    Now consider how one would go about proving statement 4. below,

    4. To be perceivable -> To be physical

    from what we know.

    2. To be perceivable -> To exist [true] [we know]
    2a. To exist -> To be physical [Physicalism] [necessary for 4]
    Ergo,
    4. To be perceivable -> To be physical

    Statement 4. To be perceivable -> To be physical presupposes physicalism [statement 2a. To exist -> To be physical]. In other words the argument for physicalism that people might be tempted to present (see below)

    1. To exist -> To be perceivable
    4. To be perceivable -> To be physical
    Ergo
    5. To exist -> To be physical

    is actually the one below:

    1. To exist -> To be perceivable [True]
    2. To be perceivable -> To exist [True]
    2a. To exist -> To be physical [??? Physicalism. Necessary for 4]
    4. To be perceivable -> To be physical [2, 2a Hypothetical,syllogism]
    5. To exist -> To be physical [Physicalism. 1, 4 Hypothetical syllogism]

    Basically, considering statement 4. To be perceivable -> To be physical to be true presupposes physicalism [2a. To exist -> To be physical] and this makes the argument for physicalism circular - begging the question.

    Numbers and logical laws are intelligible, not physical. — Wayfarer

    This amounts to rejecting statement 4. To be perceivable -> To be physical. Please go through my argument which I've summarized below for khaled.


    That would mean that by your definition their mental image is a physical thing — khaled


    Well, that's correct but not by my definition. It has to be correct for physicalism to be true.

    I'll state the physicalist argument for your consideration.

    1. To exist -> To be perceivable [Has to be true for physicalism]
    2. To be perceivable -> To exist [True]
    3. To exist -> To be physical [??? necessary for 4]
    4. To be perceivable -> To be physical [from 2, 3 and necessary for 5]
    Ergo,
    5. To exist -> To be physical [Physicalism]

    In other words, Physicalism is a circular argument [3 (a premise) is necessary for physicalism to be true but 5 (the conclusion, Physicalism) is just a restatement of 3.

    A note on the critical statements 1 and 2.

    For statement 1 to be false, there must be something that exists that's unperceivable. If so, consider the statement that's undeniably true:

    6. To be physical -> To be perceivable [matter, energy and the laws of nature are perceivable]

    From statement 6, we get the following,

    7. To be unperceivable -> To be non-physical

    For statement 1 to be false, let's suppose that y is the thing that exists but is unperceivable. Then,

    7. To be unperceivable -> To be non-physical
    8. y exists & y is unperceivable [statement 1 is false]
    9. y is unperceivable [from statement 8]
    10. y is non-physical [from statements 7 and 9]
    11. y exists [from statement 8]
    Ergo,
    12. y exists & y is non-physial [from statements 10, 11]

    Notice, statement 12 is precisely what non-physicalism is.

    For statement 2 to be falsified, we need to have "something" perceivable that doesn't exist but this is impossible because there's nothing there (doesn't exist) and so how can it be perceivable? Ergo, statement 2 can't be falsified. The rest of the argument proceeds as shown.

    Now, some have pointed out that hallucinations count for things that don't exist but are perceivable.

    However, by perceivable I'm not referring to the perception of one or a handful of individuals or even measurements by instruments in a piecemeal sense. There are standard procedures for ruling out hallucinations and these are invariably scaled-up versions of the normal act of perceiving; people, more people, instruments, more instruments, you know the deal but the bottom line is the entire exercise is nothing but the act of perceiving just ramped up. In short, by perceivable I'm talking about something being perceived in this fashion - hallucinations having been ruled out. Ergo statement 2 stands as it is, in its full glory - true.

    It seems that physicalism is either false or circular. 
  • Marchesk
    4.6k
    Are physical laws observable?
  • Wayfarer
    22.3k
    How about the number 7? (Any natural number would do, but let’s keep it simple.)

    And for that matter, none of your elaborate logical (or pseudo-logical) reasoning is physical, either. It’s simply the relationship of ideas - one of which is what constitutes ‘the physical’.
  • Wayfarer
    22.3k
    There seems to be deep connection between perceptibility and physicalism. For instance, all that we know to be physical are perceptible in one way or another. In fact, the two seem to be synonymous with each other for the perceivable are classified as physical.TheMadFool

    What you’re talking about is scientific empiricism. That is, propositions must be validated by observable data. As I’ve hinted above, pure maths is already outside that domain, as mathematical proofs don’t need to be validated with respect to observable data. Consider platonic realists, such as Kurt Gödel:

    Gödel was a mathematical realist, a Platonist. He believed that what makes mathematics true is that it's descriptive—not of empirical reality, of course, but of an abstract reality. Mathematical intuition is something analogous to a kind of sense perception. In his essay "What Is Cantor's Continuum Hypothesis?", Gödel wrote that we're not seeing things that just happen to be true, we're seeing things that must be true. The world of abstract entities is a necessary world—that's why we can deduce our descriptions of it through pure reason. — Rebecca Goldstein

    Of course, this is an embarrassment to empiricists, as a consequence of which they have come up with ridiculous ideas like ‘fictionalism’. But the fact remains, rational beings perceive intelligible truths through the ‘eye of reason’. Without that ability, science would not exist, but //discussion of// that ability is not at all on the curriculum of what is currently regarded as scientific education.
  • Echarmion
    2.6k


    What about the perceiver themselves? If everything is physical and If to be physical is to be perceived by something, how is there something to perceive and create all the physical by this perception?
  • Pfhorrest
    4.6k
    Are physical laws observable?Marchesk

    In the same sense that they "exist", yes. In the sense of patterns in observable phenomena, then yes, obviously: patterns in observable phenomena are themselves observable. In the sense of human theories about what exactly those patterns are, also yes: we can observe that humans do really have those theories.

    What about the perceiver themselves? If everything is physical and If to be physical is to be perceived by something, how is there something to perceive and create all the physical by this perception?Echarmion

    This one is easy: the observer is also a physical thing. Physical things observe other physical things, and the web of all that observation (which is also interaction, physical things acting upon other physical things) is what constitutes reality.
  • Wayfarer
    22.3k
    as soon as you enclose exist in scare quotes, it’s game over for physicalism.
  • Pfhorrest
    4.6k
    The alternative is supposing that somewhere out there in space or hidden away in some kind of alternate dimension you could discover the object which is a physical law. Physical laws (and laws generally) aren't that kind of thing; they don't exist like that. But to say "physical laws don't exist" sounds like you're saying "physical things don't obey laws", i.e. "don't follow patterns in their behavior", which is of course not what is intended.
  • Wayfarer
    22.3k
    somewhere out therePfhorrest

    There’s your issue, Forrest. Everything real, for you, is situated somewhere.
  • Echarmion
    2.6k
    This one is easy: the observer is also a physical thing. Physical things observe other physical things, and the web of all that observation (which is also interaction, physical things acting upon other physical things) is what constitutes reality.Pfhorrest

    But whence the web? That is, we'd have to suppose that mutually observing observers just are, without any temporal process.

    But this isn't true for anything else we observe, so isn't this special pleading, where the observer is some special kind of physical entity that's somehow not temporal?
  • Wayfarer
    22.3k
    But to say "physical laws don't exist" sounds like you're saying "physical things don't obey laws",Pfhorrest

    What I think Platonism gets at, is that laws (etc) transcend the physical (which is also ‘the existent’ or ‘the domain of phenomena’). Put another way, the physical (or the existent) is what ‘the transcendent’ is transcendent in relation to. So it does not exist - it transcends existence. It is beyond existence, but that which exists is dependent on it. If ‘the existent’ is real, then the source is ‘super-real’. Science itself doesn’t account for scientific laws, because (Platonists would say), the source of those laws is beyond what science can discover. But of course that goes against the fundamental tenet of modern naturalism, which is that nature ‘contains its own cause’.
  • Marchesk
    4.6k
    In the same sense that they "exist", yes. In the sense of patterns in observable phenomena, then yes, obviously: patterns in observable phenomena are themselves observable. In the sense of human theories about what exactly those patterns are, also yes: we can observe that humans do really have those theories.Pfhorrest

    Let me rephrase. Is causation observable? Are those observed patterns the result of necessary relations?
  • Pfhorrest
    4.6k
    You take it from here, it's your thread and I don't feel like fighting your fight for you, I have more important life stuff I need to spend my time on.
  • khaled
    3.5k
    In fact, the two seem to be synonymous with each other for the perceivable are classified as physical.TheMadFool

    We don't "perceive" energy, or probability waves, or the gravitational curvature of space-time. We hypothesize them and perceive their effects. This is highlighted by the fact that there are different theories of mechanics and different quantum theories. There are Newtonian mechanics, Hamiltonian mechanics, Lagrangian mechanics, etc. These don't use the same concepts. Where is the space-time curvature in string theory? All of these theories explain the same phenomena by proposing differnt (unperceivable) concepts and variables.

    But to say "physical laws don't exist" sounds like you're saying "physical things don't obey laws", i.e. "don't follow patterns in their behavior", which is of course not what is intended.Pfhorrest

    Well you know it's not what is intended meaning you probably know what IS intended. What is intended is that physical laws are not physical things.
  • TheMadFool
    13.8k
    Are physical laws observable?Marchesk

    Yes. They can be seen, i.e. perceived, in action in the way matter and energy behave. I suppose one needs to think of "perception" in the broadest sense of what it means to be perceivable.

    rational beings perceive intelligible truths through the eye of reason.Wayfarer

    That's the heart of the issue. The physical is defined in terms of us being able to "perceive" or not. Ergo, the moment you say "...rational beings perceive intelligible truths through the eyes of reason." you'll have to concede that whatever it is that's being perceived is physical.

    It boils down to the relationship between perceptibility and physicalism outlined in the OP.

    1. To be physical -> To be perceivable.

    Statement 1 isn't difficult to accept. All that's physical - matter, energy, the laws of nature - are perceivable. No room for doubt there for someone who's a non-physicalist.

    2. To be perceivable -> To be physical.

    This statement provides the only opportunity for non-physicalists to validate their position for it were false, then there would be something perceivable but not physical. Your claim that "...rational beings perceive intelligible truths through the eye of reason." would then be an instance of something being perceivable but not physical. This (a perceivable thing which isn't physical) would then pave the way for a proof of non-physicalism because it no longer contradicts the essence of proving existence which is: to exist means to be perceivable to the senses/instruments.

    Let's study the situation we have more carefully:

    We have to agree, for good reason, that the statement,
    1. To be physical -> To be perceivable. [matter, energy, and the laws of nature are perceivable] is true.

    Now, if we also agree that statement,
    2. To be perceivable -> To be physical is true then it means the following is true,

    3. To be perceivable <-> To be physical

    Statement 3 is just another way of saying,

    4. The physical = The perceivable [The physical is defined as the perceivable]

    Now, let's see how existence relates to perceptibility. We need to do this because non-physicalists claim that some things are not physical which is another way of saying non-physical things exist.

    As far as I can tell, the relationship between existence and perceptibility can be expressed as,

    5. To Exist -> To be perceivable

    And statement 5 is equivalent to,

    6. To be unperceivable -> To not exist

    Now, if physicalism insists that the following is true,

    2. To be perceivable -> To be physical

    then it would mean,

    7. To be non-physical -> To be unperceivable

    But, if 7 is true then, taking 7 along wih statement 6, the statement about existence, we get the statement,

    8. To be non-physical -> To not exist

    In other words, non-physicalism is about nonexistent things!! Nonexistent things are Nothing! Non-physicalism is about Nothing! Absurd!

    If you disagree then, you must falsify the following two statements:

    2. To be perceivable -> To be physical

    and/or

    5. To exist -> To be perceivable

    That's to say non-physicalists have to prove

    9. There are perceivable things that are non-physical

    and/or

    10. Unperceivable things exist

    We can't prove statement 10. Unperceivable things exist i.e. we can't reject/falsify statement 5. To exist -> To be perceivable because Nothing is unperceivable and that's why it's nonexistent. If I say, for instance, that here's x, x is unperceivable and exists, I wouldn't be able to distinguish x from nothing, both being unperceivable.

    Nothing doesn't exist because it's unperceivable i.e. we're using the following statement in deciding the nonexistence of Nothing,

    11. To be unperceivable -> To not exist

    and statement 11 is equivalent to statement 5. To exist -> To be perceivable

    So, rejecting/falsifying statement 5 would mean, at the very least, Nothing could exist. Another Absurdity!

    Going by how some philosophers talk of the mind being non-physical, I'd have to say that non-physicalists are rejecting statement 2. To be perceivable -> To be physical because the mind is perceivable but the claim is, it's not physical i.e. statement 9. There are perceivable things that are non-physical is true. So, from a non-physicalist point of view, mind can't be matter, can't be energy, and, at this point, we can forget about it being some kind of law of nature.

    Now a summary of all that's been said.

    5. To exist -> To be perceivable [can't be falsified]
    2. To be perceivable -> To be physical [necessary premise]
    Ergo,
    12. To exist -> To be physical [Physicalism] (from 2, 5 Hypothetical Syllogism)

    If now physicalists claim premise 2 to be true then that would imply the following statements are true,

    13. To be perceivable -> To exist [this is true even considering hallucinations because for existent things, perception is a sufficent condition in order to infer existence]
    14. To exist -> To be physical [necessary but ???]

    The whole argument now looks like this:

    5. To exist -> To be perceivable [can't be falsified]
    13. To be perceivable -> To exist [true for reasons above]
    14. To exist -> To be physical [necesary but ???]
    2. To be perceivable -> To be physical [from 13, 14 Hypothetical syllogism]
    Ergo,
    12. To exist -> To be physical [2, 5 Hypothetical Syllogism]

    In other words, physicalism begs the question. There's a circularity [premise 14 and conclusion 12] in the physicalist's position.

    Wayfarer, what say you?

    :chin: :chin:

    perceive their effects.khaled

    That's all that counts.
  • Harry Hindu
    5.1k
    Are dreams and hallucinations perceivable/physical? What about the majority of the universe that is unobservable?
  • Wayfarer
    22.3k
    ..rational beings perceive intelligible truths through the eyes of reason." you'll have to concede that whatever it is that's being perceived is physical.TheMadFool

    Numbers and logical laws are intelligible, not physical. The 'eye of reason' is an allegorical expression - when you see that 2 and 2 is 4, you're seeing something that cannot be perceived by the physical senses but only by reason, only by an intelligence capable of counting. So you're seeing an intelligible truth, not a physical fact. We do this all the time, without noticing that we're are doing it - it's taken for granted. So we see through the 'eye of reason', without noticing that they're doing it, and then we're so inattentive that we don't even notice that this is what we're doing. :-(

    what the Empiricist speaks of and describes as sense-knowledge is not exactly sense-knowledge, but sense-knowledge plus unconsciously introduced intellective ingredients, - sense-knowledge in which he has made room for reason without recognizing it. A confusion which comes about all the more easily as, on the one hand, the senses are, in actual fact, more or less permeated with reason in man, and, on the other, the merely sensory psychology of animals, especially of the higher vertebrates, goes very far in its own realm and imitates intellectual knowledge to a considerable extent. — Jacques Maritain
  • khaled
    3.5k
    That's all that counts.TheMadFool

    So when an artist imagines something and draws it that counts as "perception of effects" right? (since they couldn't draw it without imagining it). That would mean that by your definition their mental image is a physical thing.

    Similarly according to your definition hallucinations would be physical things (since they can be perceived, by definition)

    Also numbers now become physical things, since the effects of using them are observable.

    Once you start including things like imagination among the set of things that are "physical things" the word physical becomes redundant. We're just talking about things in general now. The way you define it, there is no such thing as a non-physical thing in the first place. Which means you're not a physicalist, it's more accurate to call you a "thingist".

    I don't think that when non-physicalists propose a non-physical concept they would do so despite the concept not having any effect. Since any concept with any effect will always be "physical" to you, it must follow that even these "non physical concepts" (numbers, imagination, etc) are physical. At this point you've blurred the line between physical and non-physical and are now just talking about things.
  • leo
    882
    Take your favorite physical theory. It refers to fundamental physical entities and relate them through equations, which dictate how these entities move. These entities do not perceive anything. There is no way to derive from these equations that a combination of these entities will perceive anything. In order to have a combination of these entities that perceives something, you need to inject consciousness (the ability to perceive) at some point, which is not a physical entity.

    Hence physicalism is nonsense.
  • TheMadFool
    13.8k
    Numbers and logical laws are intelligible, not physical.Wayfarer

    This amounts to rejecting statement 4. To be perceivable -> To be physical. Please go through my argument which I've summarized below for khaled.


    That would mean that by your definition their mental image is a physical thing.khaled

    Well, that's correct but not by my definition. It has to be correct for physicalism to be true.

    I'll state the physicalist argument for your consideration.

    1. To exist -> To be perceivable [Can't be falsified]
    2. To be perceivable -> To exist []
    3. To exist -> To be physical [??? necessary for 4]
    4. To be perceivable -> To be physical [Necessary for 5]
    Ergo,
    5. To exist -> To be physical [Physicalism]

    In other words, Physicalism is a circular argument [3 (a premise) is necessary for physicalism to be true but 5 (the conclusion, Physicalism) is just a restatement of 3.

    A note on the critical statements 1 and 2.

    For statement 1 to be false, there must be something that exists that's unperceivable. If so, consider the statement that's undeniably true:

    6. To be physical -> To be perceivable [matter, energy and the laws of nature are perceivable]

    From statement 6, we get the following,

    7. To be unperceivable -> To be non-physical

    For statement 1 to be false, let's suppose that y is the thing that exists but is unperceivable. Then,

    7. To be unperceivable -> To be non-physical
    8. y exists & y is unperceivable [statement 1 is false]
    9. y is unperceivable [from statement 8]
    10. y is non-physical [from statements 7 and 9]
    11. y exists [from statement 8]
    Ergo,
    12. y exists & y is non-physial [from statements 10, 11]

    Notice, statement 12 is precisely what non-physicalism is.

    For statement 2 to be falsified, we need to have "something" perceivable that doesn't exist but this is impossible because there's nothing there (doesn't exist) and so how can it be perceivable? Ergo, statement 2 can't be falsified. The rest of the argument proceeds as shown.

    Now, some have pointed out that hallucinations count for things that don't exist but are perceivable.

    However, by perceivable I'm not referring to the perception of one or a handful of individuals or even measurements by instruments in a piecemeal sense. There are standard procedures for ruling out hallucinations and these are invariably scaled-up versions of the normal act of perceiving; people, more people, instruments, more instruments, you know the deal but the bottom line is the entire exercise is nothing but the act of perceiving just ramped up. In short, by perceivable I'm talking about something being perceived in this fashion - hallucinations having been ruled out. Ergo statement 2 stands as it is, in its full glory - true.

    It seems that physicalism is either false or circular. :chin:
  • khaled
    3.5k
    For statement 2 to be falsified, we need to have "something" perceivable that doesn't existTheMadFool

    A hallucination.

    To be physical -> To be perceivable [matter, energy and the laws of nature are perceivable]TheMadFool

    Again, I think this definition of perceivable is confusing. Being able to see the effects of something doesn't mean you saw the thing. If I hear knocking at my door I can postulate that there is a thief there. That does not make it the case that I perceived a thief there. I could also postulate that it's Amazon. Again, that does not make it the case that I saw an Amazon employee there.

    In other words, Physicalism is a circular argumentTheMadFool

    Not much of an argument then.
  • TheMadFool
    13.8k
    A hallucination.khaled

    :ok:
  • MondoR
    335
    1. To be physical -> To be perceivableTheMadFool

    Perceived by who?
  • TheMadFool
    13.8k
    Perceived by who?MondoR

    This is an entirely new line of inquiry and you seem to ask this question as if a perceiver is necesssary for perceiving but you draw this conclusion from a world that could be a hallucination which isn't a good idea as far as I can tell.

    That means all you have to go on to make your case is your own perceiving and to infer a perceiver from that is to beg the question because that's exactly what needs to be proven.
  • bert1
    2k
    TMF, what is the difference (if any) between physicalism and monism, for you?
  • 8livesleft
    127
    There are limits to what we can perceive and there are limits to the tools that we have therefore we can't say with absolute certainty that some things don't exist.

    This might not always be the case but I think that it will take a while before the universe and all the forces acting within are fully known.

    But that also doesn't mean that all those fantastical supernatural things exist either.
  • Wayfarer
    22.3k
    Take out the ‘non’ in the title and I’ll take a look. :-)
  • unenlightened
    9.2k
    Circularity is a good thing for a theory, as long as it isn't vicious. A theory is a way of looking at things; at least, this is a way of looking at theories and ways of looking at things.

    The problems begin when one wishes to claim that there is only one way of looking at things - this is a way of looking at things that is quite obviously faulty.
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