I'm sorry that we haven't been able to reach agreement, despite our numerous exchanges. But I have both good and bad news about the impasse. In part, our disagreements stem from the fact that I'm using some terms in a different way from you. Once these differences are made explicit, then the areas of disagreement become much clearer. The bad news is that some claims that you and other Objectivists find obviously true seem to me incorrect. I haven't been able to grasp what you take to be so evident about these claims. I will give examples below.
Well, if you say that light (which travels at 186,000 miles per second) does not travel at 186,000 miles per second, you're saying that light is not light, and that's a contradiction.
I wrote, "All right. Then please tell me how the fundamental constituents of the universe (which were not created and were here from the beginning, as it were) could have failed to exist. They were not created, so there is no creator that could have chosen otherwise -- that could have created something different instead. So, how could these primary existents have failed to exist? The possibility of an alternative -- i.e., of non-existence -- simply doesn't apply to them."
Possible by what standard? Nothing in existence could have made them possible. The fact that one can imagine other ultimate constituents having existed does not mean that they're possible. I can imagine running a mile in 4 minutes, but that doesn't mean that it's possible.
Here I think our disagreement stems from the fact that I take the laws of identity and non-contradiction in a formal way. As I understand it, a contradiction has the form "p and not-p". "Light, which travels at 186,000 mps doesn't travel at this speed" is, as you say, a contradiction. "But "light doesn't travel at 186,000 mps" isn't formally a contradiction. To get a contradiction, you have to add the premise"light travels at 186,000 mps." Even if it is implicit in the concept "light" that it travels at this speed, you need to add the premise to arrive at a formal contradiction.
So what? you may say. Well, suppose we are considering,"It's possible that light doesn't travel at 186,000 mps, even though this is always its speed in the actual world." We can show this is a contradiction if it is an essential property of light that it travel at the speed it does travel in the actual world. Following Peikoff in "The Analytic-Synthetic Dichotomy", you hold that things have their properties essentially. There are no contingent facts, and the actual world is the only possible world.
This is your ontological understanding of the law of identity. But why should we accept this ontological understanding of identity? You are certainly right that imagining a state of affairs does not show that it is possible, but it hardly follows that real possibility is confined to the actual world. What exactly is your argument against someone who denies that all objects have fixed natures that include all their properties? It wouldn't be a good response to say that this supposition contradicts the law of identity, since just what is in question is whether the law of identity understood this way should be accepted.
You can approve or disapprove only of that which is open to man's choice.Are you using "approve" and "disapprove" so that that it is definitional that they apply only to what is open to man's choice? If so, why can't we say that we like or dislike states of affairs never subject to human choice? What is supposed to be the impropriety in saying, e.g., "I don't like dinosaurs. T. rex makes me feel icky."
That ideas are based on sensory experience is an observable fact, is it not? Ideas apply to experience, but I don't think their origin is an observed fact.
I don't follow you. If one can perceive similarities and differences without a prior concept, why can't one recognize similarities without a prior concept?I'm sorry; I didn't write clearly. The argument of the critics of abstractionism is that even if we can grasp similarities and differences without a prior concept in some simple cases, e.g., colors, there are more complicated cases where we can't do so without a prior concept. I'm not sure what to make of this criticism. In a paper that I'm sure you are familiar with, David Kelley discusses some of these criticisms and offers an Objectivist response to them.
I think that Rand is assuming a self-aware robot, one that could value its own self-preservation.Thanks for your clarification of the robot example.I don't think it adds support to Rand's argument. If I've got this right, she is saying that without the choice of life or death, there could be no other values. To help us grasp this point, she imagines an immortal robot. The robot wants to preserve itself, but since it is indestructible, it doesn't need to do anything to continue to exist. All activity is then pointless for it. But Rand has just said that any activity would be pointless: she hasn't given any reason to accept this. Only someone already convinced that value depends on the possibility of death would accept her conclusion about the robot.
This example will show what I take to be wrong about the way she uses the robot argument. Suppose someone says that life only has meaning if you embrace a collective to which you are willing to sacrifice your life. You disagree. The person asks you to imagine a man stranded alone on a desert island with no hope of rescue. The collectivist says that in that situation, the person on the island will find life meaningless, since there is no collective to which he can sacrifice his life. Unless you are already inclined to accept his view, you won't find what he says persuasive. He has simply made up a story that has the outcome he wants.
(Edited by David Gordon on 5/22, 8:36pm)