Why does everyone say that a planet has to be somewhat similar to Earth in order to have alien life?
If our life came about due to chance mixing of available materials, then shouldn't that happen anywhere with any available chemicals?
according to the evolutionist viewpoint..
“If our life came about due to chance mixing of available materials, then shouldn’t that happen anywhere with any available chemicals?”
No, because there must be certain chemical reactions to provide the pathways for utilizing sources of energy, chemical and light, to fuel growth, reproduction, motility, and so forth. Carbon and Silicon working in various combinations with compounds utilizing such elements as Hydrogen, Oxygen, Nitrogen, Sulfur, Iron, Phosphorus, Manganese, and others are required to produce organic molecules and polymers necessary to organize for feeding and reproduction. Exobiologists have identified some of these yet to be discovered alternative pathways for biochemical reactions. Most, however, require conditions of pressure and temperature more closely akin to Earth-like environments due to our current ignorance of more extreme environments and their highly exotic chemistries. Jovian class planets for example have enough pressure to form water compunds into a form stronger than steel.