This article was originally posted on RealClearScience.

Viruses are among the weirdest things on the planet. Existing in a Limbo-like world somewhere between the living and the dead, viruses present undergraduate microbiologists with their very first philosophical conundrum: What is life? The question may be forever impossible to answer because even though viruses evolve — as do other bizarre creatures such as transposons and prions — they continue to defy our understanding of what it means to be “alive.” Continue reading →