For so long we have referred to “qi,” without actually describing what qi is so that we all know what were are talking about. Lifeforce, energy and so on are words. Through experience we interpret them, but if you have no experience, defining qi becomes more elusive.
Qi is change. Not like “spare change” as in money, but shifts that occur in the position of the body, for example. In order to shift you probably need a shift in the mind. Perspective has to change. You need to discern more subtle positions of the body and the feeling of flow. Qi flows. One way to identify qi is to seek out places in the body that have nothing flowing through them. This understanding is achievable by everyone who tries, I believe.