Science
Scientific, empirical (verifiable by observation or experience rather than theory or pure logic), testable and observable methods, are the best means for determining what is real and what is imaginary. By using our senses and extensions thereof, using various technologies, we embark upon an ongoing, accelerating process that is self-correcting whenever new discoveries are made. As an example, we are able to observe gravity and measure its properties, and although we don’t yet fully understand it we do have definite proof of its existence.
There is a considerable amount of pseudo science where real science findings are distorted and misrepresented. Unwarranted conclusions are drawn or one theory is chosen out of many others so one must carefully check the sources to see if they are reliable and generally accepted by most of the academia as “proof.”
Philosophy
Philosophical speculations and theories which could lead to experiments, and great discoveries are, in themselves, not proof of anything until scientifically verified. Many philosophical ideas have turned out to be viable but many have not and must be disregarded. Ancient philosophers have given us great insights but their lack of scientific knowledge produced unviable philosophies, in many cases, such as the geocentric model of the cosmos proposed by Aristotle and Ptolemy.
Faith
Faith, which is belief in speculations and suppositions created in the brains of human subjects, is not reality. Humans have evolved a strong desire (instinct), an evolutionarily useful trait, to develop rituals to influence the powerful natural forces and to predict the future through heavenly observations. Rituals, such as praying and offering among many others, attempt to counter the fear of death and to promote wishful thinking. They are founded in emotions rather than knowledge.
Illusions
Illusions are distortions of the senses. There are many forms of illusions. There are optical and auditory illusions which sometimes are taken to be real and used as “proof” of the supernatural.
Delusions
Delusions are held with strong convictions even when superior evidence to the contrary is presented, Cognitive dissonance also plays a role here. Dreams, hallucinations (which can be natural or drug induced), spiritual experiences, mass-hypnoses, mass- hysteria and other delusions are perceived as “reality” but they are not proof of the existence of the supernatural.
In conclusion, the scientific method is the only method available to tease out reality. Before we accept any speculation requiring a supernatural explanation, we should first find scientific proof through the scientific method that this speculated phenomena exists. Otherwise, although philosophy is a useful endeavor that can lead to scientific discovery, we waste our time on Faith, Illusions and Delusions. We have no substitute for the scientific method.