One of my favorite TV shows as a teenager was a series called Arthur C. Clarke’s Mysterious World. This was a 13-part British television series looking at all manner of unexplained events, weird phenomena, and urban myths from around the world, introduced by the famous science-fiction writer and futurist Arthur C. Clarke. The series divided up its subject matter into three categories of mysteries.

Mysteries of the First Kind are phenomena which were inexplicable and baffling to our ancestors but are now well understood, mostly thanks to the knowledge we’ve gained through modern science. Obvious examples include natural phenomena like earthquakes, lightning, and pandemics.

When mysteries cross over to dangerous irrationalities, they can have detrimental effects on our well-being.

Mysteries of the Second Kind involve phenomena that are yet to be explained, but which we are confident have rational explanations that we hope to find one day. These phenomena are only mysteries because we have yet to understand them. Examples might include the original purpose of Stonehenge, the prehistoric circle of giant stones in Wiltshire in England; or in physics, the nature of dark matter, the invisible substance that holds galaxies together.

Mysteries of the Third Kind include phenomena for which we have no rational explanation, nor can we see how we could ever have one without rewriting the laws of physics. Examples include psychic phenomena, accounts of ghosts and other-worldly apparitions, alien abductions or fairies at the bottom of the garden, all of which not only fall outside of mainstream science, but which have no basis in reality.