Imagination is a rearrangement of what was previously experienced. When we speak of zombies, for example, we are speaking of things we have experienced in the past but in a different arrangement. The concept of zombies is meaningful even though we have never experienced a zombie as a whole. We have experienced every single element zombies are made of but we haven’t experienced these elements in the arrangement that defines zombies. It is a meaningful concept because it is possible for us to experience zombies. At the present date, we only have an experience of their imitations. Imitations being objects that have a number of features but not all of the features that the object they are imitating – the original – has. It is rightful to say that when you see a zombie on a computer screen or at a halloween party you are seeing an imitation of zombies and not real zombies. But there are also words that are meaningless in the sense that they do not refer to anything that can be experienced. The concept of perfect circles, for example. It is meaningless because it is not something that we can experience. It is neither something we have experienced in the past as a whole nor a rearrangement of what we have experienced in the past. You cannot imagine a perfect circle. You can only pretend that you can. And because of this, there can be no approximations of perfect circles. You cannot approximate what the word refers to when the word does not refer to anything. I can be proven wrong, sure, but this would require that someone demonstrates to me that it is possible to experience perfect circles. If you DENY that words are meaningful only if they refer to something that can be experienced then we have a serious problem. A very serious problem.
Another word that most people throw around without understanding what it really means is “universe”. The word, if it means anything, means a model of reality or quite simply a theory. Or it might mean whatever set of assumptions one holds to be true. Assumptions being guesses regarding something we haven’t experienced. A theory is nothing but a set of instructions on how to calculate (or determine) what’s going to happen next based on what happened in the past. In fact, it is a broader concept than that. It is quite simply a formula i.e. a set of instructions on how to calculate (or determine) some output values based on some input values. A theory can be quite simply a mathematical function that relates a point in time with a set of events that happen at that point in time. Now, when people speak of “the universe having a beginning and an end” they are in fact speaking about theories that have a specific feature. Namely, they are speaking of a category of theories that calculate events only for a finite range of points in time e.g. a theory that takes a point in time as an input but only within a specific range. Say if time is measured relative to some event, the function may accept only real numbers between -6000 to +billion where 1 represents a single day, positive numbers days after the pivotal event and negative numbers days before the pivotal event. So far so good. What they are saying is meaningful. What these people are doing is they are asking a very simple question that has the form “if there is a theory that represents exactly how the universe works, does this theory have a time limit?” Let us acknowledge that these people do make a difference between what people think is how the universe works (i.e. theories that people have that do not necessarily exactly represent how the universe works) and how the universe REALLY works independently from what anyone thinks. The problem is that they IGNORE how humans create theories. In other words, they ignore EPISTEMOLOGICAL ISSUES. They are stuck speculating about what’s possible i.e. they are stuck exploring possibilities. In this particular case, exploring all the possible theories that can exist. They never, for example, ask whether the theories they come up with can be INFERRED from any kind of evidence that is imaginable. Why bother exploring “what ifs” that can never be proven? For example, suppose that there is a theory that represents exactly how the universe works, how can we determine which one of the infinitely many theories is the one that represents exactly how the universe works? There is no way to do so. We don’t know what we HAVE to do because the procedure is undefined. Basically, such a theory cannot be inferred from any kind of evidence we can imagine. The actual theories they come up with are not meaningless. What is meaningless is the assumption that there is a theory that represents exactly how the universe works. It’s a meaningless phrase.
The problem with the universe having a beginning and an end is not merely that there is no evidence to back it up but the fact that no evidence can back it up.