I am having trouble understanding how the idea of qualia and p-zombies is logically coherent. If philosophical zombies are conceivable, and behave exactly the same as human beings, then zombies would also claim that they possess conscious experience / qualia, even though they do not. Doesn't it then follow that our conviction that we have qualia cannot be DUE to us actually having qualia, since zombies would hold the same conviction? Thanks.

No, it doesn't follow. Compare: If an evil demon were thoroughly deceiving me right now about my surroundings, then my current perceptual experience would -- unbeknownst to me -- be unreliable. But the truth of that conditional doesn't imply that my current perceptual experience is -- unbeknownst to me -- unreliable. Likewise, if zombies are possible, and if they claim that they have conscious experience, then it follows that claiming to have conscious experience doesn't imply having conscious experience. But we knew that already.

Can we perceive the natural laws, which have shaped our ability to perceive?

I'm not sure I would use quite the verb "perceive" to describe our cognitive grasp of natural laws, but I don't see any reason why we can't discover at least some natural laws, including those that have shaped our ability to perceive (or discover). That is, I don't see any reason why a natural law's having shaped our ability to perceive should make that natural law especially hard for us to discover. It's not as if we should think of natural laws as having purposely shaped our ability to perceive in order to keep themselves hidden from us.

Why do we need a contrast to recognize a sensation? For example -; Think of hearing the same sound since your birth and think that you are hearing it without any variations. We will fail to recognize that we are perceiving a sensation and we won't be able to recognize the sense organ. Iam only 15,Forgive me if my question is fallacious. Thanks.

Thanks for your interesting question. I don't think there's anything fallacious about it. But I do think that, at bottom, it's an empirical question -- one that we can't expect to answer just by thinking hard about it. What you say in answer to it seems plausible to me: If all that I ever receive at my auditory organs is a totally undifferentiated sound, no matter what I do, then it's hard to see what function my auditory organs are performing for me or why I would even be aware that I had them. But I think that a confident answer to your question depends on properly gathered empirical data. You might look into the psychology literature to see if anyone has investigated this topic.

Regarding the age old conundrum of the tree falling in the forest. According to Barclay, there is no sound if there is no mind to hear it. I am thinking that there may be no human around hence no human auditory organs to absorb the waves and send the message of "sound" to the brain.....but that is a bit anthropocentric. The forest is full of creatures that have auditory organs, so some brains will hear the sound....some minds will perceive the sound of a crashing tree, no? (listening to Nigel Warburton's A Little History of Philisophy)

I agree. I don't know what Berkeley says about whether any nonhuman animals possess minds, but on his view, I take it, nonhuman animals would need to possess minds in order to perceive anything. Indeed, according to Berkeley, not only does the tree make no sound unless a mind perceives the sound, but the tree doesn't even exist without a mind to perceive it. (Even if no finite mind perceives the tree, Berkeley attributes the tree's existence to the tree's being perceived by God's mind.) Notice, too, that if we construe "a sound" dispositionally, i.e., as simply a disturbance that would be heard if there were a normally equipped listener to hear it, then sounds can occur even with no listeners (human or nonhuman) on the scene.

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...

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 .