It is hard to say exactly when this idea became an ossified dogma of the modern physicist, but it was perhaps around about 1970 or 1980. After discovering the forces of electromagnetism and gravitation centuries earlier, scientists discovered two more forces in the twentieth century: the weak nuclear force and the strong nuclear force. Then somewhere along the line, physicists seemed to erect a great big “Mission Accomplished” banner, rather like George W. Bush's team did on an aircraft carrier a few weeks after the initial invasion of Iraq in 2003. Physicists came to believe that they had figured out all of the important forces at work in the universe.
The central dogma of modern physics
A modern physicist is someone with great confidence that he understands every major force at work in the universe. He is willing to consider that there may be new types of matter that he doesn't know about. He is willing to consider that there may be some unusual type of energy that he doesn't know about. He is willing to consider that there may be whole other universes he knows nothing about. But the modern physicist draws the line at considering the possibility of unknown forces at work in our universe. No, no, no, he thinks to himself, we already have all the forces of the universe figured out.
Perhaps we can understand this vaunting affectation if we think of it as a kind of firewall. Admitting any unknown force at the work in the universe might open the door to possibilities many a physicist wishes to exclude, such as the idea that what is going on in the universe is not merely the result of blind chance. To lock out such ideas that make them uncomfortable, physicists cling to the pretension that they understand all forces at work in the universe.
Later some serious difficulties arose in understanding the universe. It seemed that the known force of gravitation just was not doing the job adequately at explaining the structure of the universe. None of the other four fundamental forces works on a large scale. The physicists and cosmologist had a choice: they could either concede the existence of some unknown force at work in the universe, or they could start believing that almost all of the matter in the universe was invisible (the doctrine of dark matter). Strangely enough, they chose the second of these beliefs. The average physicist seemed to think: Much better to believe that most of the matter in the universe is some weird, invisible, unknown matter than to believe in the terrifying idea that there is an unknown force at work in the universe.
Later on cracks started to show in this model. It seems that the positions and motions of dwarf galaxies are not consistent with the theory of cold dark matter, as discussed here and here. Also, a just-released scientific paper (entitled “Cosmic Discordance”) shows a problem with the cold dark matter model, as shown in the diagram below. The blue part shows estimates made using dark matter theory. The purple part shows data from two major space satellites. The purple part and the blue part are supposed to overlap, but they do not. The deeper blue part and the deeper purple part (the most likely values) are far apart. Message from this graph: we are lost in the cosmic woods.
But have physicists now started to doubt dark matter? Have they conceded their approach may be wrong, and that there may be forces at work in the universe they don't understand? No, they're clinging to their cold dark matter theory as zealously as ever. It's needed to prop up the central dogma of physics, that there are no major undiscovered forces.
A corollary of this central dogma of physics is that there can be no earthly forces we do not understand. So any paranormal phenomena involving some unknown force is taboo, strictly prohibited. A long-running project involving random number generators around the world has apparently shown deviations from randomness whenever important events happen, as if global consciousness was mysteriously affecting the random number generators by some unknown force. But such results must be wrong, a physicist would tell you, because it involves an unknown force, and we understand all the forces at work in the universe. Such phenomena are excluded on the grounds that they are “occult.” The word “occult” simply means hidden, but what could be more occult than the physicist's assertions that most of the universe’s matter is some invisible, unknown, hidden type of matter (dark matter)?
We saw this central dogma of physics at work recently when two sets of tests (including one done by NASA) indicated that some new type of space drive works, apparently using some new type of force. Physicists jumped quickly to their keyboards to in effect tell us: the tests can't be right, because there can't be some new force we don't understand.
Perhaps the best way to refute the central dogma of physics is to consider the Big Bang, the explosive origin of the universe. According to modern science, the entire universe began to expand from an infinitely dense mathematical point about 13 billion years ago, a point called the primordial singularity. Can we really claim that we understand all the forces that were involved in that infinitely strange event, or that it only involved the forces known to us? Can we have any confidence that such an unfathomable event of infinite mystery involved only the small number of forces we know of? Of course not.
At some time in the future a wiser generation of physicists will realize that our knowledge of the universe is merely fragmentary, and that the universe is greatly affected by mysterious forces and phenomena that we know nothing about. Scientists will realize that they have been like little children playing at the seashore with a few interesting shells, while the great ocean of truth lay undiscovered in front of them (to borrow a great simile from the great physicist Isaac Newton). Scientists will then take down the “Mission Accomplished” banner raised prematurely by a generation of physicists who thought they had figured out all the forces at work in the universe.