This theme was ever popular in the 19th century -- Well's novel about the Invisible Man, or Bierce's short story about a man eaten alive by an invisible animal, are typical. Again, this is a physical impossibility. In order to be invisible, an object would have to have two characteristics, which are totally unrelated. It would have to be transparent, and would also have to have an index of refraction that is exactly equal to that of air. A transparent object (like glass or quartz) is not invisible, because it does not have the same index of refraction as air. But in fact no solid object (or liquid object) can have an index of refraction anywhere close to that of any gas at normal temperature and pressure. What is more, air does not have a fixed index of refraction it varies with pressure, temperature, etc. But all solids and liquids have fixed indices of refraction. To show that the idea of invisibility involves practical contradictions, imagine an invisible boat. A transparent boat with the same index of refraction as water would be clearly visible in air (as is a splash of water), and thus "invisible" only below the water line. If we instead made it have the index of refraction of air, the part below the water line would be clearly visible (like an air bubble in water). Also, a boat made of a transparent material, like glass, would not be too seaworthy! In the laboratory, one can find liquids, which have the same index of refraction as certain glasses. If a piece of such glass is completely immersed in such a liquid, it cannot be seen (although it would easily be felt by putting one's fingers in the liquid) -- but it would show up on radar or sonar. This does not seem too practical!
Note also the following: in general, there is no way to make a material that is not transparent. Transparency is a more-or-less intrinsic property of objects, determined by the way the atoms or molecules of the object are bonded to one another. A final comment: an invisible creature would also be blind! Eyes work by absorbing light.
"THE FOURTH DIMENSION"
The general claim is that there are "other" space dimensions, somehow at right angles to the three we know, and if we could "learn" to move in these other dimensions (usually only one other, the fourth) we could do apparently supernatural things, like instantaneously travel from one spot to another, penetrate solid through solid, etc. The fact that all forces whose ranges are not otherwise limited fall off with distance exactly as the inverse square, to a very great measured accuracy, indicates directly that there are no more than three space dimensions available to matter and to forces and everything in the universe is made of matter and acted on by the same four forces. Physicists and mathematicians routinely work in abstract spaces of arbitrary numbers of dimensions even infinite numbers of dimensions. Further, modern efforts to unify the electromagnetic, weak, and strong nuclear forces, which are understood quantum physically, with gravity, which is understood only classically, sometimes involve working with many actual space dimensions, 8 or more. This is a mathematical trick to make an incomplete theory generate possibly realistic numbers, and has nothing to do with the actual number of space dimensions. In these theories, called "supersymmetric theories," all higher dimensions have to be made compact, curled up on themselves, so that particles cannot move or forces propagate along them, otherwise the theories would not work at all! These theories are just things for physicists to play with until they find a quantum theory of gravity, and have no particular physical significance at present.
An obvious comment is that if actual higher dimensions did exist, nothing could "prevent" matter, forces, or us from moving in those directions to begin with, and we would know about them from the beginning, just as we know about forward, sideways, and up.
These are usually confused by pseudoscientists with the "fourth" dimension and "parallel" worlds, two totally unrelated ideas. The original 19th Century fantasy fiction theme of coexistent worlds is that since we see only a very limited part of the full electromagnetic spectrum, maybe there are features of the world of which we are unaware for instance, if we could see by ultraviolet light maybe New York City would also be a jungle! We wouldn't be aware of the jungle since it can be seen only in ultraviolet light. If this claim makes sense to you, you have a lot to learn about nature. In each of the last three themes, writers almost always confuse "invisibility" with "intangibility." A blind man can't see the curbstone, but that doesn't prevent him from tripping over it! An object, which could not be seen, could still be felt, and its existence would be obvious! Furthermore, an object, which reflected only ultraviolet light, for instance, would be clearly visible. Why? An object, which does not reflect visible light, appears black to our eyes. A jet-black tree is just as visible as a regular tree, at least in the daytime.
Physicists in the 19th Century were very interested in vibrations and waves. Writers of popular fiction, and pseudoscientists, took only these words, and used them as buzz words. (A buzzword is a word, which is meaningless in context, and usually is applied too broadly to so many things that no meaning could possibly be assigned to it in its customary -- non-scientific -- applications.) Thus writers started saying things like "everything is made of vibrations, and the only difference between one thing and another is the rate at which is vibrates, its frequency. If I could change my vibration rate to that of platinum metal, I would become platinum metal." This is the 19th Century origin of the 20th century buzz word "vibes." "The vibes are not right today for me to do this job." It makes no more sense to say that things are "made of" vibrations than it does to say they are made of "sidewise motions" (what is moving?) or that they are made of "temperature" (what has the temperature?). Matter is made of atoms. Atoms may or may not vibrate; it's the atoms and their properties that are important.
Nineteenth century physicists were also extremely interested in the concept of energy. In physics, "energy" is a bookkeeping device for keeping track of the amount of work that has been done on or by a system. In popular fiction, "energy" became a buzzword, and finally a kind of substance. Science fiction writers and pseudoscientists today talk about things made of "pure energy." Since temperature, for instance, is a direct measure of internal kinetic energy, to say something is "pure energy" makes no more sense than to say something is "pure temperature." This is gibberish, without any connection to the world we live in. Energy is not a substance or a thing. It is a number (with units of work) and it is not the number of anything.
Another ever-popular idea from 19th century fiction was, "what if?" What if the South had won the Civil War? What if Napoleon had not invaded Russia? Characters were struck by lightning or something and woke up in another world in which history had taken some other turn. It makes a good novel, but it has nothing to do with the world we live in. In its purest form, this is a na�ve "concrete" interpretation of the abstract concept of probability the claim that if the coin is 50% likely to fall heads, and 50% likely to fall tails, it has to do both the universe splits into two universes, in one of which the coin falls heads, in the other of which it falls tails. Since almost everything that happens in the universe is a matter of probability, and since an almost limitless number of processes are taking place in each split second, one is talking about an almost limitless number of "new" universes being born every split second. Of course, one can talk about anything. There is, however, nothing in the real world corresponding to the concept of parallel worlds. In modern physics one does encounter what are called "multiple vacua." The present state of the universe is not the only possible state. For all we know the whole universe could suddenly make a "phase transition" to a different vacuum, in which all the fundamental constants and laws of nature would be totally different, and things as we know them would cease to exist. But this possibility has nothing whatsoever to do with the concept of "parallel universes," which are instead more often confused with "higher dimensions," "coexistent worlds," etc. A good 20th century science fiction novel dealing with parallel worlds is Keith Laumer's Worlds of the Empirium; see also H. Beam Piper's "Pratime" series.