In the traditional Yoga, when one wants to think or know something, one uses three means. One is direct perception, that is directly observing the phenomena using eyes, touch, hearing, taste and smell. When this is not possible, but things observed are known signs of what was previously known through direct perception, one uses deduction. When things are beyond the perception or deduction, one uses a valid testimony of an extremely reliable (but through belief) source. In this case too, it is understood or assumed that the source had a direct perception of the phenomena, which is extremely hard for a common person. To give a parallel example, a neurosurgeon has a knowledge of some internal parts of the brain through direct perception. But, a common person cannot have it, so there is a need to trust in the neurosurgeon’s words.
In certain stages of Yoga practice, one develops a special ability called intuition, which is called mystic ability in some circles. Here a person gets flashes of phenomena that others are not observing. Let us call this mystical sense.
We are concerned with usage of the direct perception, deduction and mystical sense. It is obvious that when a phenomena can be directly observed, one should use direct perception. When direct perception is not possible, but a deduction can be made, one should use that. A mystical sense needs to be used only when all other possibilities are exhausted.
It is interesting to see that some people use mystical sense for ordinary things such as knowing whether a shop is open. In most of such cases, a person does not have the mystical ability they are claiming to have. But, even if they have, it would be a gross misuse of this sense for ordinary things that can be directly known.
In the similar way, when it is known that a person has a bad diet, person is not having proper rest and exercise, these issues must be address, and not usage of Reiki, Tarrot Cards, Palmistry, Astrology, etc.