If a person hears a story that he finds hard to believe, and he desires more evidence for the truth of that story, then that happens to be the correct use of the philosophy of skepticism. But the philosophy of skepticism which posits that no human can know for certain that anything is real or not real in his experience can only be atheistic because if God is real then He would have created a real universe and real human intelligence and not a creation that might be an illusion.
But humans can know for certain that all of their experiences are real. When a person examines every sense experience and every inner experience that one can have, one finds that every element of those experiences happens to be useful in some creative way. Every impression on consciousness cannot be anything except an experience. Illusions are never useful except for fantasy writers. Fantasy writers can make even illusions useful for entertainment purposes.
Intelligence is a process of being creative. Every intelligent human can assemble the elements of their experiences into combinations of ideas that prove to be useful and beneficial or prove to be useless or even destructive. In other words, humans can have good ideas and bad ideas. But the elements of both systems, good and bad, are always useful in other combinations of ideas and that which is useful cannot be an illusion because illusions are usually useless except for fantasy writers. Humans can invent systems that produce beneficial results, or humans can invent systems that fail to produce beneficial results, but in both cases, only useful elements can be used. In this regard, the creative process is similar to mathematics. 2+3=6 happens to be a useless combination, but every element of that false combination happens to be true and real in beneficial combinations.
But in order for the creative process to work properly, intelligence must know the difference between something and nothing. The idea of nothing never means that a particular something does not exist. When one says that something, such as a winged horse, is not real, the useful idea of nothing can never annul the elements of that experience. Illusions always comprise real elements. When a person says that something does not exist, one always means that a false combination of real elements does not exist in combination with each other. For example, if a person makes a mistake in arithmetic and adds 2+3=6, that person can then recognize that that combination of real and useful elements means nothing, but that person cannot conclude that that false combination is not real because it equals the real and useful idea of nothing. For another example, if a person sees a UFO, that person can conclude that it was real, or he can conclude that because of misapprehension or hallucination, that which he saw was not real. But he cannot conclude that the real elements of his experience that he saw such as "shinny," "metallic," "disk," or "flying" were not real, but only that their false combination was not real. The idea of nothing is real because it serves a useful purpose.
Opinions and theories may not be known to be true or false because not enough evidence has been accrued to demonstrate their truth or falsity, but nevertheless, every opinion and theory always comprises true and real elements of experience.
All of this means that everything that one can experience must be real. All of the elements of something can only be real because they are all useful in beneficial combinations. The idea of nothing must also be real because it is useful for the identification of systems that are useless and mean nothing. Every element of experience has meaning which makes it real. In order for creative intelligence to work properly, it must be able to tell the difference between that which is useful and that which is useless so that it can be usefully discarded or ignored. Thus, intelligence consciousness can recognize that its elements of experience are all useful, and therefore, real. The element of consciousness that is the idea of nothing is also real because it can usefully identify systems that are useless and mean nothing. Everything is real.
If anyone should doubt the conclusions of this philosophy, then that person should examine every elementary sense object, every idea, every feeling, and every word that they have ever experienced, and they will find that they are all useful for the creation of both useful and useless systems. Even nonsense words are useful because one can use the idea of nothing to recognize that they mean nothing. One can even recognize that one's idea of nothing can only be real because it is useful for the identification of all that is useless.
God created a real universe and real human intelligence. Genesis 1:1; Genesis 1:26-27 (KJB).