Original by Bert Hubert
What is life?
This question keeps many people awake at night and has led to rafts of definitions, some involving features (procreation, metabolism and so forth), some involving chemistry, entropy or energy flux and some are of a more philosophical bent. A BBC article noted there are over 100 definitions of life and it claims all are wrong.
And indeed it does appear to be quite a challenge - every hard and fast rule is violated somewhere in biology. There are things that are clearly alive, but never replicate. Plants typically do not move yet are extremely vital. Viruses do make copies of themselves, but need a host to do so. Are they alive? And once you have it all figured out, some wise person comes up with a crystal that somehow manages to create copies of itself, and points out that these copies even ‘inherit’ characteristics. Is the crystal alive? Similarly, “fire” consumes elements, moves and even replicates. Yet calling fire