There is a lot of excitement in the media today about water being discovered on Mars and its implication for finding life there. Some people seem to think that finding water means we have found life.
Let’s put aside the assumption that life must be common in the universe because it arose “spontaneously” on earth then evolved totally by chance to produce us, and look at the logic being ignored by many people.
Back when I did maths at High School one thing that was emphasised in the more advanced subjects was the difference between “necessary” and “sufficient” conditions in proofs.
For example, apart from the number 2, it is necessary for a number to be odd if it is to be prime. However it is not sufficient to show that a number is odd to prove it is prime.
Another example is it is necessary for a car to have fuel in the tank in order to drive it, but that is not sufficient- you need a driver with the key, air in the tyres, an engine that works, and much more.
Returning to Mars, we know that water is essential for life. This is so axiomatic that the scientists looking for life on other places, make that the starting point in their search. No water no life.
But life requires more than water. It needs carbon, nitrogen, phosphorus and, above all else, energy.
Water is a necessary condition but it is not sufficient.
Some scientists are so pessimistic about the ability of life to spontaneously emerge from the primordial soup that they believe that the existence of life on earth in itself suggests there must be an infinite number of parallel universes to allow for the possibility that on just one planet in one of those universes life arose all by itself.
To me that is grasping at straws. It makes much more sense to believe in a Creator who made everything that is out of nothing. As Genesis 1:1 says “In the beginning God created the heavens and the earth.”