The strength of Wells as a prophet was that he was a natural pessimist. Strongly influenced by the theories of Charles Darwin as taught by Thomas Huxley, he could see that humans were in one sense just another species, and biological species naturally appear, flourish, and eventually decline and become extinct; thus, the vision of extinction at the end of The Time Machine. One particular prediction occurred in a passage near the end of The Time Machine: before the final vision of the cold deserted shore, the time traveler sees strange animals, possibly degenerate humans, fleeing from a giant centipede, and later sees an enormous crab. Today, scientists believe that if a nuclear holocaust or other worldwide disaster occurs, insects and their relatives may well be the only survivors; this is one Wells prediction that may come true, but if it does, of course, no one will be around to confirm it.

In the nearer future, Wells had the ability to look at any impending development and instantly see all of its worst implications, so that, for example, he fully foresaw the wide range and ferocity of modern scientific war. Specifically, he foresaw the use of tanks and the characteristics of air warfare—the ease of destroying targets, the breaking down of the barriers between soldiers and civilians, and the difficulty of seizing and holding territory with air power alone. Wells, unlike other prophets, also understood economics. Many people predicted technological marvels, but thought that either future people would all be rich, or these marvels would be so wonderfully cheap, that virtually everyone would have them; individual airplanes for the masses. Wells realized that future inventions might be affordable only to the rich and privileged; individual airplanes for the wealthy few. Indeed, his firm belief that class differences would persist in the future, and might even widen and harden, might be considered one of his most accurate predictions.

But beyond this natural pessimism, Wells also wanted to be useful, to help humanity improve, and he realized that pessimistic visions were not a useful incentive. So, he suppressed his pessimistic thoughts to present optimistic, utopian futures, as a better way to inspire progress. This thought is directly supported by a passage in Wells's first novel, The Time Machine. The Time Traveller first says he "thought but cheerlessly of the Advancement of Mankind, and saw in the growing pile of civilisations only a foolish heaping that must inevitably fall back upon and destroy its makers in the end." This is Wells the logical pessimist. But he goes on: "If that is so, it remains for us to live as though it were not so." This is Wells the forced optimist. Wells's determination to pretend that the coming end of humanity "were not so" led to a number of weak works, most notably Men like Gods. It is interesting to note that one major dystopia, Aldous Huxley's Brave New World, began as a parody of Men like Gods, and I suspect that Wells himself would actually have agreed with many criticisms of that book that Huxley was offering. But he wanted to be an inspirational prophet, not necessarily an accurate one. One could see, then, The Time Machine and Men Like Gods as the defining poles of Wells's thought: one freely expressing his natural pessimism about human progress and the future, the other determinedly projecting an optimistic and inspirational human future.

Overall, then, the one prophecy Wells repeatedly made which has not been fulfilled was that humanity would, at some point, respond to the horrors of modern science and society and, as a result of their shock, would become mature, grow up as it were, and thus establish a benevolent world government and eliminate crime, injustice, and so on. Perhaps he actually realized that this would never happen, but he thought it was helpful to assert that it would someday occur, possibly as a way to actually inspire such a maturation.

Wells also could envision a future society that changed socially as well as scientifically. He foresaw that sexual mores would become more liberal, that social nudity and free love might be common in the future. Amusingly, a paperback edition of The Time Machine published in the late 1960s tried to present the Eloi as Wells's prediction of "the flower children"—hippies. Narrowly speaking, of course, the Eloi, other than their love of flowers, had no real kinship with the hippies; but in a broader sense, the philosophy of the hippies was to an extent one that Wells anticipated and would have approved of: enjoyment of casual sex, a carefree lifestyle, and an overarching sense of social responsibility and concern.

Wells was keenly aware of scientific developments in his time, and scattered throughout his works are many specific predictions. Atomic bombs drop in fiction for the first time in The World Set Free. The reawakened Sleeper enjoys a miniature visual entertainment that resembles a modern television with VCR. The premise of Star Begotten—that aliens might be somehow altering human lives on Earth—and the premise of In the Days of the Comet—that a cloud from a comet might influence human behavior—might be said to anticipate the modern theory that life on Earth actually had extraterrestrial origins. Like many others, he anticipated a more logical system of phonetic spelling, and while others focused on more exotic forms of power, he saw the potential of simple wind power in When the Sleeper Wakes.

Generally, Wells's vision of the future seems accurate. He foresaw that class divisions would not vanish with progress, but rather that progress would tend to accentuate them, so that the rich would get richer and the poor would get poorer, and so that the benefits of progress would chiefly affect a few privileged people, while the lives of most people grew worse. He foresaw the growing urbanization of life, and the growth in population, so that the world in effect might become like one large city. And he foresaw that humanity's future would largely involve life on the planet Earth. Wells has been criticized for not paying much attention to the possibilities of space travel, but that may only reflect a belief that space travel would not significantly affect the lives of most people, who would continue to live on Earth.