This thread is an offshoot of The fundamental concepts of physics are all based upon metaphysics. Hmmmm, OK... ex·pand v. intr. 1. To become greater in size, volume, quantity, or scope: Air expands when heated. This critic's influence is expanding. 2. To speak or write at length or in detail: expand on a favorite topic. 3. To open up or out; unfold: The chair expands to form a day bed. 4. To feel expansive. u·ni·verse n. 1. All matter and energy, including the earth, the galaxies, and the contents of intergalactic space, regarded as a whole. 2. The earth together with all its inhabitants and created things. 3. The human race. 4. The sphere or realm in which something exists or takes place. 5. Logic. See universe of discourse. 6. Statistics. See population. I see nothing in the definitions of "expand" that requires a larger embedding space for a universe to expand into. In fact your charge of language abuse is a bit ironic because it is in fact the position taken by yourself that I see more frequently charged thus. You haven't explicitly stated your reasons for your quote above, but I'm going to go out on a limb and assume that they are the usual reasons that I have seen for similar conclusions on philosophy boards all over the internet. My apologies if your argument is better than the following. Physicist: The universe is all that there is, by definition. It is also expanding. Skeptic: Well, if it's expanding, then what's it expanding into. Physicist: Nothing. The universe is all that there is, remember? Skeptic: Well, the universe can't expand into 'nothing', because 'nothing' does not exist. So if the universe is expanding into 'nothing' then that's just another way of saying that it isn't expanding at all! The above argument by Skeptic pays lip service to the truth that 'nothing' does not exist (by definition). But it tacitly (and mistakenly) denies that truth by treating 'nothing' as an existent in drawing the conclusion. In more formal terms, the conclusion is reached by committing a linguistic (!) fallacy known as reification of the zero. When Physicist said "nothing" he didn't mean that the universe was expanding into something, and that thing is called 'nothing'. He meant simply, "the universe isn't expanding into anything", which is far from being the same thing. It would be the same if Physicist were to tell Skeptic that "no one can travel at the speed of light", and then Skeptic turn around and start looking for this mysterious person called "no one" who is zipping around, keeping pace with his own reflection in the mirror. (This analogy with the speed of light was originally brought up by the member Eh. Credit where credit is due, and all that.) Now you, Hector, say that logic prohibits the universe from expanding. But since you didn't state your reasons for saying this, I have to ask, does the above argument by Skeptic reflect your logic? I'm curious because there are big problems with his logic!