It is hard to believe that there are other realities beyond what can be seen, heard, felt, smelled or tasted. Yet when one turns the mind's eye away from what is outside and looks inside, another world becomes known. This can be verified by oneself, provided the effort is made to quiet and concentrate the mind. Yet we humans are filling the planet with more and more devices to delight and entertain the senses, so that the last several generations have been losing interest in inner worlds, losing the ability to go there, and even failing to recognize that they exist or have value. People conversant with both worlds will tell them that this is where problems are solved, that inside is the realm of true happiness, where you can experience that all forms of life are one form of life, and that harming others in any way leads to your own suffering.
The trend away from otherworldly knowledge was noted by Carmen Blacker when she chronicled Japanese shamanism in the 1960s for her book The Catalpa Bow:
"The world view uncovered by the shaman's faculties, with its vision of another and miraculous plane which could interact causally with our own was the basis for the more advanced mystical intuitions of esoteric Buddhism. Today, however, this world view is fast disappearing. The vision of another plane utterly different from our own ... has faded. Instead the world has become one-dimensional; there are no barriers to be crossed."
To repeat Shakyamuni Buddha's words, "This Dharma is for one who delights and rejoices in the Unworldly, not for one who delights and rejoices in worldliness."