Peter wrote:
"I appreciate your responses because they have given me a great deal to think about (although, unlike your proselyte/devotee godless, I actually use my own mind and come to conclusions on the matter rather than simply taking your word for it)."

You're welcome, Peter. I hope one day you come back and review our exchanges, and maybe even develop the courage to investigate Objectivism seriously, since I think doing so would really help your understanding. There are a number of sources which I can recommend to you if you become serious about this. However, so far, it seems you are trying to argue against it without a firm grasp of it, and I'm concerned that this can only cause confusion for you. Anyway, so be it, this is how you've chosen to proceed, so let me get to the rest of your post.  

Peter wrote:
"Once again, having thought about this issue, I remain unconvinced by your arguments."

Peter, of course this does not surprise me. As I've pointed out numerous times already: you reject reason in favor of a confessional investment which you claim on the basis of faith. This is not compatible with reason, and to the degree that you commit yourself to this investment, you surrender reason. Those who claim their position on the basis of faith concede that reason is on the side of their adversaries. This is what the theist does every time he claims that there is some supernatural entity or dimension. It makes no difference whether he claims it is one of the Christian gods, a Mormon god, a Jehovah's Witness god, a Muslim god, a Hindu god, a minor tribal god, etc. Each is an expression of the same false view of reality, called the primacy of consciousness. And the only way one can "argue" on behalf of such beliefs is by accepting a string of stolen concepts, which I have exposed repeatedly in your attempts to argue for this belief.

Peter wrote:
"Let us, for the moment, stick with the issue of what existence is (specifically, whether it is physical or not).  After we hammer this part out, we can continue on."

I really do not know what your hang-up on this matter is, and why it is so important to you that existence must be either physical or non-physical. As I've indicated in the past, this concern of yours is irrelevant to first philosophy, and I see your effort here as only an attempt to introduce a false dichotomy. As I've emphasized before, the Objectivist position is that existence exists, and that whatever exists, exists. It makes no difference if a particular object or attribute is later determined to be physical or something else, it still exists. The essential which you should be concerned about recognizing is the fact that existence is not a product of consciousness, and this fact destroys god-belief at its root.

Peter had written:
"The only argument that I am putting forward is the existence does not need to be physical."

I asked:
"Existence of what?"

Peter now responds:
"Why, the existence of existence.  Remember "existence exists"?"

See, I knew Peter would fall into this trap. Now he is reifying a concept, which is a conceptual fallacy. It is the failure of distinguishing between essentials, namely between the metaphysical and the epistemological. This move is an expression of the primacy of consciousness view. But as I have clarified in the past, the concept 'existence' is a collective noun; it refers to all the things which exist. Without reference to things which exist, the concept 'existence' has neither meaning nor context. Peter seems to want that all the objects which exist must either be physical or non-physical. But why? What motivates his intention here? Must apples be 'non-physical'? He is welcome to believe this if he truly does. But I do not. Apples exist. And they do not become non-physical if Peter denies their physicality. Denying something doesn't make it vanish any more than wishing makes something true (since consciousness does not hold metaphysical primacy over existence). If Peter can produce apples which are 'non-physical' for the group, this would still not supply the necessary evidence to support his position. He speaks of 'need' here, and also reifies this. He's chasing up a dead tree here, and I think it's apparent why he does so.

Peter had written:
"I have proven this by demonstrating that if all perception is perception of an illusion, existence would still exist because the one perceiving must exist to perceive something, and must also be conscious. That existence, however, is not necessarily physical."

I asked:
"I'm wondering how you think your intended conclusion follows from whatever your premises are. Can you present your argument in the form of a lucid syllogism? What do you mean by "necessarily" here? Are you denying that there is anything physical? If so, why? If not, then what's the point?"

Peter wrote:
"The point is that you cannot disprove my argument.  It is consistent with itself."

Peter, simply because something is "consistent with itself" does not make it true. I do not accept any onus to "disprove" your argument. I merely point out that it makes grave conceptual errors. By doing so, I point out how your argument merely collapses under the weight of its own fallacies. You seem quite oblivious to this, as here you come back over and over again repeating the same errors after they've been pointed out to you time and time again. Not one instance of the many stolen concepts which you have accepted and incorporated into your arguments have you corrected since I've pointed them out. I'm quite convinced now that you are unaware of the nature and seriousness of this error. The fact of the matter is most likely that you accepted your god-beliefs without any awareness of the nature of stolen concepts, and thus accepted those stolen concepts uncritically. Now you have invested yourself emotionally into a commitment to those god-beliefs, and, like someone who's invested his life savings into a dwindling stock, you cannot bring yourself to bear recognizing the error of your choices. So, you remain committed to spite yourself, and meanwhile you busy yourself with rearranging all the deck chairs on the Titanic. And it's all on record for us to see. Naturally, this causes you resentment, which you refocus into your zeal for trying to prove one gnat's worth of a philosophical point, a point which misses the point to boot. I really think you might need a therapist, as I've seen your condition before, and it can get much worse if it goes untreated. (Have you ever heard of Jim Jones and David Koresh? There is a psychological causality associated with their ends, and it's always in the form of a god-belief.)

Peter wrote:
"Do I personally believe in a physical existence?  Yes, I do.  Does it matter in this debate?  Not one bit."

If it doesn't matter, then why are you so concerned about proving that "existence is not necessarily physical"? I think you're becoming schizophrenic here Peter.

Peter wrote:
"Why?  Because we are dealing with important issues that need to be thought about, not merely assumed."  

And that's precisely one of the beauties of Objectivism. In Objectivism, we identify in explicit terms those facts which people assume and take for granted all the time, facts which philosophers themselves have traditionally taken for granted, or, worse, thought needed to be proven in order to be justified in accepting them. Objectivism identifies the stolen concepts associated with this error, and returns those concepts to their proper place in a rational philosophy. And if Peter would take his own advice here (namely, "deal with important issues that need to be thought about, not merely assumed") in relation to a genuine investigation of rational philosophy, he might find that he might learn something of significant value. However, it seems that he is confessionally motivated to remain committed to a primitive worldview which has no value to thinking individuals and no place in a rational society. And the only way he can make that primitive worldview seem to "work" is by launching into a long string of conceptual gimmicks. Luckily, we don't have to fall for them.

Peter wrote:
"(And, I must point out, that I not only believe in a physical existence, but also in other forms of existence that are not physical.)"

Peter, good for you. We're all happy for you, honest.

Peter wrote:
"By 'necessarily' I mean simply what all philosophers mean: the conclusion must follow from the premises."

But if existence is properly axiomatic (which it is; it is irreducible and primary), then it cannot be a conclusion. Again, you're exposing your commitment to stolen concepts here. It's obvious you have not taken the time to see this.

Peter wrote:
"I have perceived contradictory things
"There can be no contradictions in reality
"Therefore: My perceptions are not 100% accurate."

Is this a formal syllogism? What is the form of the argument? This is not a form of modus ponens or modus tollens. Perhaps it is a form of modus Petris?

Anyway, let's look at the first premise: "I have perceived contradictory things." How does he know this? By what means does he establish this, and how did he make the determination that he has "perceived contradictory things"? I can think of one way. For instance, he probably perceived that a man named Jesus said he would "return" during the lifetimes of his audience (cf. Matt. 16:28, et al.), and also perceived that Jesus did not live up to this prophecy (Christians are still waiting for this "return" to this day). Thus, he concludes, he has perceived two items - the one a claim about reality, the other reality itself - and has found that they are in contradiction with one another. He also states that "there can be no contradictions in reality," which I accept (and by so doing I recognize that the idea of 'miracles' is thus invalid), and then concludes from these premises that his "perceptions are not 100% accurate." However, it is unclear exactly how he concludes this from these premises (he introduces a new key term "100% accurate" in his conclusion, and this is a logical no-no). Does he question the fact that he accurately perceived what Jesus is portrayed to have said in the gospels? Probably not (since he is confessionally bound to claiming that these sayings are true). Does he question the fact that Jesus has not lived up to this promise? Well, he would appear to be an even bigger fool than some might already think he is, so he dares not in order to keep his appearance of self-esteem intact. So, what does he do? He internalizes the error of his assumptions to conclude that the error is in him, not in reality or in Jesus. He cannot make sense of the contradictory claim by wedding it with a rational view of reality, so he rejects reason outright, committing a reversal in the process (entailed in the idea that perceptions can be measured for accuracy before they can be "trusted"), and then implying (by application of this conclusion to gross generalization) that no one at all can be 100% accurate in their perceptions (since to assume otherwise would give away the game). No, Peter, I do not accept this argument. At root, it is an example of what one can conclude when he confuses the what with the how of cognition. A rational philosophy equips a thinker with the proper tools necessary to avoid such errors.

Peter wrote:
"--Note: by the way, I will point out another interesting thing to think about here is color-blindness.  We know that if someone cannot see a particular color, that does not change reality--yet the person who is color blind can in no way distinguish two lights.  I speak from experience as my father is color blind and, were it not for the placement of the lights on a stop light, he would not know when the light was red or when it was green."

But that's the point: How do you know that the light was really red and not non-red? Don't you see the stolen concepts in what you want to conclude here? I suppose not. Colorblindness is not an example of "inaccurate perceptions." Those who are "color-blind" are seeing true to their form of perception. This is not an "error" of perception by any means. There is a lot of research done on such matters, and it's obvious that you are unaware of it. See Kelley, David, The Evidence of the Senses, (Baton Rouge: University of Louisiana, 1986) for some very telling discussions of these issues.

Peter wrote:
"Supposing all reality is only physical"

Who is claiming that "all reality is only physical"?

Peter wrote:
"and all information must come through our senses"

Information about what?

Peter wrote:
"Reality is viewed through perception
"Perception is not 100% accurate
"Therefore: Reality cannot be known with any certainty."

Oh, this is ripe. Look at the first premise: "Reality is viewed through perception." This kind of statement obviously implies the diaphanous model of consciousness, which Objectivism shows to be invalid (again, see the book by David Kelley which I referenced above). It fundamentally ignores the fact that perception is a level of consciousness, not merely a piece of equipment which consciousness optionally makes use of. The statement forming the first premise of Peter's syllogism here is compatible only with a misunderstanding of the nature of consciousness, and nowhere does Peter attempt to argue on behalf of its validity. Above he had stated that he wanted to "deal with important issues that need to be thought about, not merely assumed," but here he's merely assuming something himself.

The second premise is one which he takes from the previous syllogism, and I've already explained a few of its problems and why one should question its supposed truth value.

Lastly, it is uncertain exactly how the conclusion follows. He introduces a new term in his conclusion ("certainty") which does not appear in any of his premises. This is considered a suspicious move in logic. Key terms must be introduced and related in a formal argument's premises. When one introduces a new key term in the conclusion, its relationship to the terms in the premises is at best vague. A careful thinker would avoid this.

Peter wrote:
"Existence exists is a statement of reality
"Reality cannot be known with any certainty
"Therefore: existence exist with any certainty."

Look at this argument: Even if we could accept each of the two premises, it is unclear how (if at all) the conclusion follows. It commits the fallacies of composition and context-dropping. For instance, while I might not be able to achieve certainty in what an object's identity is (perhaps I've never seen it before, and its attributes are initially puzzling to me), I can still be certain that it exists. In other words, here Peter is confusing the what (knowledge of what an object's identity is) with the that (knowledge that the object exists, apart from knowledge of what exactly it is). But this only undermines the proper hierarchical nature of knowledge, which Peter seems willing to ignore (a consequence of accepting stolen concepts). Before we can identify what an object is with any certainty, we have to recognize that it exists. Otherwise, our statements about things have no reference to reality (i.e., to objects that exist). Thus, we have another stolen concept here. All errors like this are avoided in a rational philosophy.

Peter wrote:
"Perception comes via consciousness
"I perceive things without any certainty
"Therefore: I am conscious of things without certainty of whether those things are so."

Again, we have the diaphanous model of consciousness implied in the first premise: "Perception comes via consciousness." Rather, the truth is, perception is one level of consciousness. Peter seems unaware of the difference here. Look at the second premise: "I perceive things without any certainty." But certainty is a conceptual, not a perceptual matter. Again, another category error. The concept 'certainty' pertains to our level of confidence in conceptual matters, i.e., matters of identifying what we perceive. This is a conceptual task, not a perceptual task. Furthermore, we can be certain that we perceive something, even if we are uncertain what that something is. Appeals to illusions and hallucinations do not overturn this fact. In fact, appealing to illusions and hallucinations can only reinforce this position, otherwise one would have to accept more stolen concepts (which unfortunately Peter seems quite willing to do).

Peter wrote:
"Consciousness comes from existence
"I am conscious of things without certainty of whether those things are so.
"Therefore: I exist to have consciousness to have perception of things which I am not certain whether those things are so."

If Peter accepts that he is "conscious of things without certainty of whether those things are so," then how does he achieve certainty that he exists? Peter does not say. How does he know that what he possesses is consciousness? Peter does not say. If he investigates this matter fully, he will find therein a stolen concept (if he learns how to identify them).

In the end, it appears that Peter is certain that he can prove to us that he is unable to achieve conceptual certainty on anything he perceives, for this is where his skepticism will lead him if he follows it through logically. If this is the position which he wants to defend, then so be it. I think the rest of us have better things to do with our time.

Peter wrote:
"If we deny all physical existence, existence still exists."

If we deny all physical existence, any physical existence which exists will still exist. It does not disappear simply because you have a bad case of denial. Denying that which exists has no philosophical value.

I wrote:
"Thus, Peter can deny all physical existence to his heart's content. But if physical existence exists, then physical existence exists."

Peter wrote:
"But you cannot prove that physical existence exists."

And I do not claim that I can. Indeed, I do not need to prove it. Existence exists. By definition, anything which exists, physical or not, is included in this reference. It is a universal axiom, since it applies to everything which exists, regardless of its particular attributes or nature.

If I said that I could prove that existence exists, physical or otherwise, then I would have to commit myself to a stolen concept. But, since I recognize this, and since I recognize the axiomatic nature of the concept 'existence', I don't see any reason why I should do this. Indeed, I see where this leads others, and I have no desire to join their misery.

Peter wrote:
"By what means are you going to prove it?"  

See above.