The first point is that not everyone would accept the presupposition of your question. Most obviously, theists wouldn't. According to many varieties of theism, the First Cause of the material world is not a material thing. Needless to say, not everyone agrees. But you can deny that there is a non-physical First Cause without denying that the very idea is incoherent. There are homelier examples. On at least some views, the fact that something was absent can be a cause. Absences, however, aren't material objects. (In fairness, they aren't non-material objects either.) So the first point is that it isn't simply agreed by the parties to the dispute that only material objects are causally efficacious. We could also add that even among materialists, broadly understood, most would say that events rather than objects are what do the causing, but it's at least arguable that events are in space and time and so even if they aren't material objects , they're physical in a broader sense. The...

Your distinction between something not yet defined and something for which there could never be a definition is a reasonable one, and thus an answer that bears only on the former doesn't answer your question. Here's one possible approach. If something exists, it has some properties or other; for every property a thing might have, the thing either has it or it doesn't. If that's right, then we might say that nothing could be that thing unless it has that set of properties. And in that case, we might say that the set of properties "defines" the object, whether or not any finite list could capture all the properties. That's a rough sketch. It would need careful spelling out and it would also be subject to various objections; leave those aside. The point is that if we look at things this way, the notion of "definition" we're appealing to needn't have anything to do with how limited creature like us get a grip on the object. If this line of reasoning is correct, then nothing could exist unless...

You're quite right to be skeptical of the idea that physical reality needs observers to exist. But very few people who work in foundations of quantum mechanics would disagree. Bohr never claimed otherwise. What he insisted is that in describing quantum experiments, we have no choice but to appeal to classical concepts. There's room to argue about what that means, but nothing I've ever read by Bohr suggests that measurements are necessary for the very existence of physical systems. The same is even more clearly true of Bohmian "pilot-wave" interpretations. Bohmians claim that there really are particles that really have positions and trajectories---whether or not anyone makes measurements. It's just that the details of these trajectories aren't accessible to us. Everettian ("many-worlds") accounts of quantum theory likewise don't hold that the existence of physical reality depends on measurement. It's true that "branching" in Everettian quantum mechanics has a connection with measurement, but this is...

Usually, when we use the word "defined," it's about words. We might ask, for example, whether the word "chair" can be defined. If a definition is supposed to rule in exactly the things that are chairs and rule out exactly the things that aren't, then I doubt that "chair" can be defined. We can, of course, say things about what typical chairs are like. But any supposed strict definition we offer will, I'm willing to bet, have various counterexamples. Typical chairs are for sitting on. But benches aren't chairs, and we often sit on benches. And some chairs---certain works of art, perhaps---aren't actually meant for sitting on. And yet there are chairs. In fact, I'm sitting on one as I type this. However, there's another use of the word "defined" that isn't about words but about things. When we ask for definitions in this sense, we're asking for an account of the nature of the thing itself. For example: it's of the nature of an electron that it has negative charge and spin one-half. Or so we might say....

Good question. Some philosophers would say that we really are fictions in just the sense that you suggest. In the case of our psychological being, the idea that we're fictions has a long history, going back at least to early Buddhism, featuring prominently in David Hume's thought, and continuing into the present with the views of such philosophers as Derek Parfit. The same sorts of arguments can be used to support the conclusion that composite physical objects are fictions, and in fact this idea is also very old. Over 2000 years ago, the Buddhist monk Nagasena used the analogy of a chariot, which he understood as a fiction in your sense, to illustrate the Buddhist idea of "anatta" or "no-self." Most of us probably have the sense that not all composites are equally fictitious. Some objects embody homeostatic mechanisms that help them persist in the face of influences that would otherwise tend to destroy them. Biological systems, including humans, are the most obvious examples. Some objects illustrate...

Holism is a pretty puzzling concept. I'm not sure the bit about "defined as wholes" necessarily gets it. Suppose I have a chair and I break one of the legs. Then I can't use it as a chair anymore, but if there's a holism here, it seems to be a thin variety. Unless we insist that spatial relations are automatically holistic, then for something to be a chair, it suffices for it to be made up of parts that have a certain spatial configuration. Of course, we single out chairs among various possible configurations because they suit certain of our purposes, but an intact chair seems to me to be no more or less a "whole" than a chair with a missing leg. The broken chair isn't a whole chair , but there doesn't seem to be much metaphysical significance there. Here's the only case I can think of that seems to me a clear case of holism. In classical physics, the state of a whole physical system is just the aggregate, so to speak of the states of the parts. If we're given the position and the momentum of...

Not quite correct. Cyclic theories still posit a Big Bang, but they also posit a cycle of expansions and collapses. This is not something I know much about but you can read a bit more here If we suppose that the non-cyclic Big Bang model is correct, then in at least one sense, the universe isn't a case of getting something from nothing: it's not an example of matter appearing uncaused in a universe where there are earlier times with no matter. Of course, that's consistent with there being no explanation of why there's matter/energy at all. That may not quite amount to getting something from nothing, but it's an idea that doesn't sit well with everyone. Some versions of the Cosmological Argument are meant to explain why contingent things (like the physical things we're familiar with) exist. The explanations typically appeal to the existence of a Necessary Being—one who's very nature requires that it exist. If there's no such being, then it might be that there's no explanation for why contingent...

I'm not sure who has written on the topic under the specific guise that you ask about, but a good deal of work on personal identity certainly bears on it. The philosopher's question would be whether reincarnation (or something like it) is possible on a physicalist view. And on at least one important account of personal identity, the answer is yes. That account is the "psychological continuity" view. It would say that if there's enough psychological continuity (apparent memories, beliefs, attitudes...) between an earlier person and a later one, then (depending on the version of the view) we either have a case of one and the same person at two different times or of two stages of one and the same person. This would be so regardless of whether we had bodily continuity, though there might well be added clauses about the later person/stage being causally connected to the earlier in the right sort of way, and/or that there not be any "competition" (i.e., no duplicates). For example: suppose you step into a...

An interesting question. Start with an artificially simple example: a stream system with the branching structure of a simple "Y." If the two upper parts were equally wide/deep, equally far from the intersection point and at more or less opposite angles to the lower stream, it's hard to see why we'd say that one was a mere tributary and the other the main stream. If one of the upper branches started much farther from the intersection, and was much wider/deeper at that intersection we'd likely say that the other branch was the tributary. Other cases might be harder to classify. All this suggests that there's a strong element of convention in the river/tributary distinction. But there's a caution. If we asked a relevant expert — a hydrologist — s/he might have things to say that wouldn't occur to casual observers such as you and I. Whether there's a more interesting distinction that hydrologists make between source and tributary for real-world rivers is something I can't say; my knowledge of hydrology...

Sure. Even if existence is not a predicate, it's at least arguable that necessary existence is. (As Norman Malcolm pointed out years ago, there really are two versions of the argument, and the second one deals with necessary existence.) We doubt that existence is a predicate because, roughly, saying that something exists tells us nothing about what it's like. Not so for necessary existence. Not just anything could exist necessarily. The computer I'm typing on is the wrong sort of thing to be a candidate for necessarily existing thing. Assuming that some things are of the right sort to exist necessarily, necessary existence would be a predicate. Whether this is a defense of the argument all things considered is another matter. But I think the point made here is fair as far as it goes. A being that merely happened to exist wouldn't be a being than which none greater can be conceived.