In the invisible darkness which shrouds each one of us as an individual, and at the same time shrouds all forms of knowledge, there are things which we do not know, things which thrive in the interstitial spaces between established forms of knowledge. The attitude towards such things of those who reflect on the state of knowledge seems to convey a self-evident fact: we wish to know those things that we do not know. To put it more aptly, we are bound to want to know those things. How could it be otherwise? If humankind is regarded as a vast collective brain which stores up its knowledge, preserving that acquired in the past, gathering and centralizing new information from all sources and making sure that it is passed on, how could we wish to do otherwise than continue to broaden this domain of enlightenment and intelligence?