Advanced Search


Hello, Is everything in the universe invisible in its natural state? This question sounds strange, and maybe it's a bit hard to see what I mean, but I'll try to be as clear as possible. Imagine yourself outside of the universe, and that there are no other living beings in it. Since the light isn't reaching your eyes, you can't see the universe. The light inside the universe doesn't mean anything to you, it's just energy. Now, if you have, let's say, a room with nobody inside, being outside of the room would be the same as being outside of the universe when it comes to the meaning of light in the room. Yes, I understand, you can't see an object if your eyes are not exposed to the light reflected off an object, but what if there is no living being to interpret the reflected light? So, maybe a better question is what does light mean to a human if there is nobody around to form an image from the light? Thank you very much.

Two replies:

1. I'd caution against equating natural with non-human, let alone with non-living. Many living beings are in their natural state despite being alive, and many (if not all) human beings are in their natural state despite being human. A hermit crab in its borrowed shell is in its natural state, and so is a human being fully clothed inside his/her house. We human beings naturally clothe and shelter ourselves.

2. Your question seems a bit like the old chestnut 'If a tree falls in the forest, and nothing is around to hear it, does it make a sound?' If a given object reflects light in the visible spectrum, but nothing is around to detect that reflected light, is the object visible? Both questions turn on how we define terms, in particular 'sound' and 'visible'. If sound is simply vibrations that would be detected by a sound-sensor were one present, then surely the falling tree makes a sound. Likewise, if 'visible' means 'would be seen by a normal human observer looking right at it under normal conditions of observation', then the aforementioned object is visible.

Does the fact that our perceptions can be represented geometrically and that

Does the fact that our perceptions can be represented geometrically and that geometry consists of eternal truths independent of the mind prove that an external reality underlies our perceptions?

I don't think that such an argument would rationally compel external-world skeptics (who say that no one can know that there's an external world) to abandon their view. External-world skeptics think that no one can know that solipsism is false, where solipsism is the claim that nothing external to oneself and one's mind exists. The solipsist won't grant that geometry consists of truths that are independent of his own mind, because he thinks nothing is. The solipsist could admit that his perceptions have a geometric character to them without having to attribute that character to something external. So I don't think solipsism can be disproven in the way you suggest.

All of this assumes that solipsism is otherwise intelligible. But one might argue that solipsism is unintelligible because it relies on the incoherent idea of a 'private language', an idea explored in detail in this SEP article.

Does our mind alter our perception of taste from the way things look and/or

Does our mind alter our perception of taste from the way things look and/or previous experiences?

The answer certainly seems to be yes. One example: learning to like something you didn't like at first. (Olives, beer, strong cheese…)

Taste isn't the only sense modality that's subject to these shifts. Most of us, I'd guess, have found that people sometimes come to look different to us as we get to know them well, for example. As we think about our earlier reactions to some musicians and some music, we may be struck by how different the same piece sounds to us now than it once did.

Obviously there are lots of interesting questions we could ask here. It seems plausible that sometimes these shifts are a matter of learning to notice things we didn't focus on at first. But as others have pointed out, this phenomenon raises more peculiarly philosophical questions. Daniel Dennett considers a pair of possibilities that seem maddeningly hard to disentangle: one might say: I used to like parsnips, but they taste different to me now. Or one might say: parsnips taste the same to me as they always did, but I don't like the taste anymore. Just what, if anything, the difference is, and what this tells is about sensory experience are issues that might well reward further attention. Some of the work to be done is almost certainly empirical, but some of it is conceptual and philosophical.

I recently read an article by a philosopher who stated that physicalism must be

I recently read an article by a philosopher who stated that physicalism must be false or at least incomplete because it doesn't adequately account for experience. For example, say you knew all the physical information involved in seeing a sunset, even if you convey all that information to a person you'll never actually describe a sunset. Say you know a blind woman (since birth) and she asks you "what's it like to experience a sunset?", do you go off saying well it's a wavelength hitting the photoreceptors in your eyes which send electrical signals to your brain, even if that's true she's still no closer to understanding what experiencing a sunset is like. The point being that you can't reduce experience (or qualia) down to purely physical information. Personally I agree that it's impossible to describe experience with just physical information, even with something as simple as the smell of an orange, you can only communicate a description of what the smell of orange smells like tautologically, i.e. "it...

One way to understand the basic argument you outline, which is advanced most famously by Thomas Nagel in "What is it like to be a bat?" and Frank Jackson in various papers about Mary the color-blind super-scientist, is like this:

1. If physicalism is true, then someone who knew all the relevant physical facts about a conscious being's experience (e.g., a bat or a person seeing red) should know what it is like to have those experiences without having had them (i.e., without experiencing sonar perception or without having seen red).

2. Someone who knew all the relevant physical facts would not know what it is like to have those experiences.

3. So, physicalism is false.

I think there are good reasons to reject both premises. Premise 2 looks like an appeal to ignorance. It does seem implausible that any amount of objective (or 3rd personal) information could allow someone to understand conscious experiences she has not experienced. But we do not really know what a physicalist theory of consciousness will look like, or what it would be like to have all the relevant information, including the theory itself. So, premise 2 may not turn out to be true.

Premise 1 is even more dubious. A physicalist theory should predict that only by being in particular physical (e.g., neural) states will one be in certain conscious states. The theory should explain why that fact of first-person access is the case. It should also be able to explain why a person (or bat) who is in a particular physical state is in a particular conscious state. But I don't see why we should expect physicalism to entail that the experiences themselves become "illuminated" from the outside.

Some will try to strengthen premise 1 to say that physicalism entails that all the possible facts are physical facts, such that knowing the physical facts entails knowing all the facts. I'm not sure what that means--that is, the use of 'facts' and 'knowing' seems to load more into the premise than a physicalist needs to accept.

(The literature on these debates is huge. If interested, you might start here:

In describing Kant's idea of the "thing-in-itself" Thomas Pogge (in response to

In describing Kant's idea of the "thing-in-itself" Thomas Pogge (in response to a recent question on this site) recently wrote that "According to this explanation, space and time are then features only of objects as they appear to us." I'm having a difficult time deciphering this statement. To me when you speak of a feature of an object you are referring to that object in-itself almost by definition. It seems like space and time could be either a feature of the world or a feature of our mind/cognition or psychic tendencies which we project onto the world but not both. To say that space/time is a feature of the world as it appears seems to involve a confusion of how language is used to speak about being. Appearances can reveal or distort being but I don't see how they can contribute to being. We don't speak of colors as features of the (outer) world as they appear to us do we? We try to figure whether colors originate in the mind or in the world and though we allow that there is some degree of interaction...

You are quite rightly puzzled by the distinction that Pogge, following Kant, draws between appearances and things-in-themselves: it's caused trouble for Kant's readers since the publication of the first edition of the Critique of Pure Reason. The distinction is, however, at the heart of Kant's project in the first Critique, and indeed, I would go so far as to claim that it's crucial to underpinning the entire Critical philosophy. (I see the first Critique as setting the foundations for Kant's overarching project, which I take to be aimed at ethics rather than at metaphysics and epistemology. This is a somewhat idiosyncratic view, but it is, I think, defensible; in any event, nothing in what follows turns on it.)

Now the distinction that Kant wants and needs to draw is between the world as it is independently of human cognizers, and the world that appears to human beings. Yet Kant does not want to claim that the way things appear to human beings is merely a way that they appear, as if they could appear to human beings in some other way: hence he wants to resist the idea that space and time are merely "features of our mind/cognition or psychic tendencies which we project onto the world." (Hence Kant says that space and time are "empirically real," thereby implying that they are not mere projections.) But Kant also wants to maintain that space and time are not features of objects considered apart from the human cognitive faculties, as if space and time, for example, conditioned God's understanding of objects: this is why he wants to maintain that space and time do not apply to things-in-themselves. (Hence Kant says that space and time are "transcendentally ideal," which means that they are not features of objects-in-themselves, apart from "the human standpoint," as he puts it in the Transcendental Aesthetic.)

Now it might seem that Kant here is trying to have his cake and eat it too. On the one hand, he says that space and time are forms of intuition, in which the world appears to human cognizers, and hence not conditions of things-in-themselves, apart from human cognitive capacities; on the other hand, he wants to claim that the way that the world appears is not some sort of illusion, to be contrasted with a veridical cognition of the world as it is in itself. I am inclined to think that the key to understanding these positions is to see that, on the one hand, Kant means to claim that only insofar as an object is conditioned by space and time can it be cognized by human beings, but that there nevertheless is a conception of objects independent of human cognitive capacities that remains open, even if objects cannot themselves be cognized by human beings apart from these cognitive capacities. By leaving open this way of conceiving of objects, Kant thereby means to reject the two options that you propose, which in fact fit together, according to which space and time would either be features of objects in themselves or mere ways in which objects appear to us.

Whether Kant is successful in making out this distinction is quite another matter, one about which his readers have been arguing since the eighteenth century. As you try to grapple with this distinction, I recommend that you reread the Prefaces and Introductions to the first Critique, the Transcendental Aesthetic, and also the Antinomies of Pure Reason. I wish you good luck in working through this thorny nest of issues!!

Do you need an earlier perception to have a memory of something?

Do you need an earlier perception to have a memory of something?

Perhaps one might well claim that one has to have some prior experience ("experience" being broader than "perception") in order to have memory. One might remember prior thoughts, abstract propositions or a sensation rather than a full perception. Memory seems (by definition) to be about the past (I cannot remember the future, though I can remember that I believe or know that something will occur in the future) and so if there is no experience in the past to recall, it is hard to see how one might have any memory at all. In this sense, memory appears to be a dependent cognitive power --it depends on the exercise of other cognitive powers. I suppose someone might claim that they remember remembering, but this begs us to ask the question: remember remembering what?

While that is my proposal (one needs prior experience in order for memory to function), the issues can be stretched a bit... Imagine God or some super-scientist made a creature (Skippy) on Monday at noon full of ostensible memories of a past that Skippy had no part it. So, imagine Skippy recalls getting her Ph.D. at Brown, the rocky divorce and the happy re-marriage that followed, and yet Skippy did not do any of these things. While this might seem to be a case of memory without earlier experiences, I suspect we would classify these as only apparent or ostensible (or even false) memories and not cases of authentic memory.

Are humans capable of feeling extreme physical pleasure as intense as extreme

Are humans capable of feeling extreme physical pleasure as intense as extreme physical pain? If that is the case what ethical beliefs would we have to change if we wanted to maximize the occurrence of extreme physical pleasure in a way that accorded with a utilitarian hedonistic ethical system?

It might be worth starting with a qualifier: for many utilitarians, "pleasure" is too simple a notion to capture what they think we should maximize. "Happiness " might be better, and "well-being" better yet. But set that aside and suppose we can make do with the word "pleasure."

On the first question – whether we can feel pleasure as intense as the pain we're capable of – it's hard to say. We're obviously capable of short bursts of intense pleasure, but whether they're as intense as some kinds of pain is hard to judge. More important, perhaps, even if the intensity of our greatest pleasures matches the intensity of our worst pains, pain seems able to go on for a lot longer; if we factor duration into the accounting, the answer seems to be no.

But suppose otherwise. Even if we're utilitarians, the goal is to maximize total pleasure; trying to maximize intense pleasure might not be the best way to do that. We might very well get far more bang for our buck by trying to alleviate suffering or by promoting more ordinary levels of well-being.

Is it at all a possibility for everyone in this world to see different colors

Is it at all a possibility for everyone in this world to see different colors but call them the same name? For example, if someone sees yellow, they call it yellow but another person sees the same color but to them it's green but since we've defined that it's yellow, they go along calling it yellow when really they see green.

This is a wonderful (and classic) question, sometimes referred to as the 'inverted spectrum' thought experiment -- but it turns out that the philosophy of color (and color perception) are far more complicated than one might intuitively think, given our everyday familiarity with and intuitions about colors ... The short, easy answer to your question is of course yes: it certainly seems conceivable that different individuals label different color perceptions with the same name (no need to insist on the stronger thesis, as you actually phrase it, that each individual's color perception is different from every other's, is there?). Moreover I believe that, on a simple level, the 'yes' answer has been empirically demonstrated, more or less: different people will identify rather different wavelengths as 'yellow' say (which is strictly neutral on what's going on inside them, but at least suggestive of the 'yes' answer). But one can get very sophisticated here and perhaps build one's way to a 'no' answer, so the best thing to do is get more familiar with the science and philosophy of color. The starting point probably should be C. L. Hardin's famous book "Color for Philosophers" ....

hope that's a useful start ....


Recently someone asked:

Recently someone asked: I wonder about the notion of a masochist as somebody who enjoys suffering. Is it possible, logically, to enjoy suffering? Doesn't suffering necessarily preclude enjoyment and vice-versa? Would it be more accurate to say that a masochist enjoys something that non-masochists consider suffering? And a philosopher responded: I think that one definition of suffering is 'pain'. And someone could gain pleasure from pain, physical, or indeed psychological. So to say that a masochist enjoys suffering sees fine to me. Well.....I don't see much clarification here. Am I the only one? I think it might be just as hard for the question asker to imagine the relationship between suffering and pleasure and pain and pleasure. Maybe suffering is a larger category than pain that logically precludes pleasure so it's not hard to see a paradox there but with the narrower connotation of pain as a physical kind of suffering you can imagine that their can be an accompanying pleasure somehow. But the...

I think what may be tripping you up here is the vaguess of terms like "pleasure" and "enjoyment," which you seem to treat not only as equivalent, but also as univocal in their reference.

There are lots and lots of different kinds of pleasures: sexual, gustatory, aesthetic, and so on. There are lots and lots of enjoyments: some are pleasures, and others have to do with doing things we like (even when they are not accompanied by pleasant sensation--think of playing tennis when your knee hurts, but you are in a really great game and playing well.

So, one can have one kind of pleasure even when one is undergoing a different kind to pain. One can have one kind of enjoyment even when is undergoing another kind of suffering. A masochist (always measured by someone else's standard of what counts as a "healthy" or "wholesome" kind of enjoyment, mind you!) is thus one who has a certain kind of pleasure or enjoyment that is somehow linked to their also being in a certain (other) kind of pain or suffering. Nothing contradictory here!

Is it possible to perceive something unconsciously?

Is it possible to perceive something unconsciously?

The question of whether there are unconscious perceptions, and if so, their nature, has received considerable attention from philosophers and psychologists from the seventeenth century onwards. One's answer to this question will reveal a lot about one's conception of perception in particular and of the nature of the mind in general. Some care is needed in approaching the question. 'Perceive' is sometimes taken to mean 'be aware of', and if it is so taken, of course one cannot perceive anything unconciously, by definition. Such a definition doesn't, however, dispose of the question, for one can either stipulate that by 'perceive', one means to 'have a mental representation' (for now, let me just stipulate that a mental representation is an internal representation that enables one to have a sense-based perception: the nature and status of mental representations is a topic that deserves considerable attention in its own right): if one takes 'perceive' in this sense, then one can have both conscious and unconscious perceptions. On this picture, all perceptions are representations, some of which are conscious and some of which are not. (The question of why some perceptions make it to consciousness is another good one that merits further attention, but I bracket it here.) There are numerous examples of unconscious mental representations, I present just one. If one is driving along the road, thinking about the question of whether there are unconscious perceptions, one may not be consciously attending to the road, but, nevertheless, one continues to follow the road, and to adjust one's driving to the road, and even, if something appears suddenly on the road, one may respond to it, even though one's attention is not focused on the road. It seems to me that one plausible explanation of this phenomenon--not the only explanation, to be sure--is to posit unconscious representations of the road. This is the sort of everyday phenomenon that provides good reason, I think, to hold that it is possible to perceive something unconsciously.