The 'hard swallow' built into science is this business about the Big Bang. ... This is the notion that the universe, for no reason, sprang from nothing in a single instant. ... Notice that this is the limit test for credulity. . . . It's the limit case for unlikelihood.

Terence McKenna was a renowned American psychonaut, lecturer and author most well known for his theories related to subjects including psychedelics and shamanism. He is particularly well known for advocating for something he called the "hard swallow big bang theory" which was his view on the way individuals interact with and interpret religion in the modern age.

At the basis of McKenna's hard swallow big bang theory was the idea that religion has become too much of a cultural accoutrement instead of a source of spiritual nourishment. He felt that individuals have become desensitized to the mystical aspects of religion and instead adopt a more "checklist" attitude toward their faith. In order to illustrate this point, he pointed to the concept of the big bang theory of the universe.

McKenna argued that until recently, the big bang theory was considered to be a radical concept met with much distrust and opposition. Its basis rested on the speculation that, "All of this chaos of matter and energy that is the universe was once one tiny point, one infinitely dense and intensely hot singularity that exploded and spread out in an effortless, perfectly choreographed dance." For McKenna, this parallel suggested the necessity for individuals to accept that, similarly, the complexity of all religious texts, philosophies, and interpretations must similarly be swallowed in one hard gulp.

McKenna believed that in order to truly grasp the essence of religious and spiritual messages, one must develop a massive tolerance for ambiguity and uncertainty. Instead of seeking a literal interpretation, potential followers must be willing to accept the idea that religious faith is often handed down as a legacy or story and may not be completely objective or even factual.

To McKenna, the hard swallow big bang theory of religion meant that individuals should consider spirituality as a complex, ever-evolving, living organism. As a part of this, he argued that adherents must strive to separate spiritual ideas from dogma and cultural expectations and create authentic relationships with their faith.

Terence McKenna's message was a profound one, challenging individuals to drop their predetermined views of religion and focus on utilizing it to find personal meaning and understanding. The hard swallow big bang theory of religion proposes that individuals must be willing to make a large leap in order to gain an understanding of the spiritual realm, no matter if it challenges conventional norms.