The ancient Chinese and Egyptians and probably others long before them, developed a concept of “life force” or “life energy” to explain some of the mystical or spiritual aspects of life. Sometimes it is related to the concept of the “soul” or “spirit” and even the health of an individual. It is a nice idea for some folks, but in physics we are constrained to study only things for which there is evidence, and there is no physical evidence of any such force or energy as “Qi”. As I mentioned in class, despite intense investigations by physicists over the past century, only 4 forces have been discovered in the Universe (a force is a physical manifestation or application of energy to cause a change). As far as we can tell, as far as thousands of investigations and experiments have shown, all physical interactions in the Universe can be described as an application of one or more of these known forces. None involve the concept of Qi.
Now, there is always the possibility that something along the lines of Qi will one day be discovered, but given that physicists have strenuously sought to find a new force and new energy in the Universe, they have found none, and certainly no Qi.
I think you can consider Qi to be a purely metaphysical concept and as such is outside the realm of science. It is not a reality as far as physicists can tell.
Science demands evidence, and the definition of “evidence” is not the same for everyone. Science — in particular the physical sciences — has very stringent criteria. One way of looking at it is that if something is not “falsifiable” (i.e., it cannot be completely disproven, even in theory), then it is not within the realm of science. This definition can be traced back to philosopher Karl Popper, but is accepted by many if not most physicists. It means for example, that since it is not possible, even theoretically, to disprove the existence of God, then the study of God cannot be part of science.
Think about it…. in order to prove that God does not exist, you would have to be able to search everywhere in the Universe, on the far side of every planet, in every galaxy, in the interior of every atom…. everywhere, all at the same instant to be sure that he had not eluded your search. And if you assume that there is a non-physical or spiritual world, you would have to search there as well. The bottom line is that you would have know everything, every fact, every situation, every object in the Universe. You would need to be omniscient. However, by definition, an omniscient being can be considered to be a god. So to disprove the existence of God, you would have to be God.
This line of reasoning pretty well tells us that we cannot disprove the existence of God, so therefore questions of God or even religion are not part of science. The same can be said for the idea of “Qi.” We have absolutely no evidence supporting the idea of Qi, but at the same time we cannot prove that it does not exist (the concept is not “falsifiable”) so it is not part of science.
I should end by noting that lots of folks without a science background appropriate scientific terminology and concepts and use them incorrectly or inappropriately. For example we could note some folks who talk about weird aspects of quantum physics to justify beliefs in a wide range of topics from ancient aliens and UFOs to ghosts and spirituality. Sometimes these folks distort and make claims that simply make no physical sense whatsoever, or they make wild claims that simply cannot be tested.
Carl Sagan is famous for saying, “Extraordinary claims require extraordinary evidence.” He was not the first to espouse this idea, but he made it clear that if you are going to make a spectacular claim, then you need to have some very strong evidence to support it. That is why claims of UFOs, alien cities on Mars, crop circles, astrology, ESP, ghosts and the like are not accepted by legitimate science. The only “evidence” offered is weak, highly suspect, easily faked, purely hearsay and/or not repeatable by observation or experimentation.
Science would give the greatest and most sincere welcome possible to any reasonable evidence of these concepts currently considered to be “pseudo science.” Finding evidence of life beyond the Earth is the goal of many astronomers and astrobiologists, so to think that they would be hostile to any real evidence is simply ludicrous. But science is also adverse to false and unsupported claims.
Oh, and yes…. “unicorns” in the Bible? This is a current item at the time of this writing. There is no geological or archaeological evidence that any such creatures ever existed. The explanations that unicorns aren’t found today are all specious, simplistic, puerile and frankly, an attempt to grasp at non-existent straws. Unicorns did not die off in the “Great Flood” and there is no evidence for them in the past…. because they NEVER existed in the first place!
There is plenty of room for science fiction and even science fantasy, but pseudoscience should be avoided as it spreads misinformation and false ideas.