The main reason for believing that no outside civilization has ever contacted earth is that no one has found any hard evidence that even suggests intelligent beings from outer space have ever contacted Earth. All claims of evidence to date have been spurious, false, or scientifically unsound. If intelligent beings from outer space ever had contacted Earth, the evidence would have been immediately and spectacularly conclusive. For example, consider the highly advanced artifacts that would be left behind by any mystic-free civilization capable of developing the energy and technology required to contact Earth. Indeed, many highly advanced civilizations throughout outer space certainly have the technological capacity to contact and travel to Earth.
Energy capacity is a direct measure of scientific knowledge and technological development.
The energy requirements for outer space communication and travel are far beyond the total energy capacity available on earth at our present level of technology. Thus, a civilization capable of contacting earth would have to be advanced far beyond our civilization. Our civilization is at that point today. In either case, most of the world's population will die and civilization will perish because of meaningless mysticism being manipulated to give false power and bogus livelihoods to the value destroyers. Such a system allows civilization to safely advance beyond the Nuclear-Decision Threshold .