Do you think that there are concepts out there that humans cannot understand no matter how hard they try? A good example would be a fourth (fifth, sixth, etc) dimension. They may exist, they may not, but if they do then humans are only capable of understanding them mathematically, not visually. I would think of more examples but my creativity box seems to be pretty empty right now. But yeah, do you think that it's possible for any idea or concept to be incomprehendible to humans?