Extremely low probability
CON: Life is very complex, even if we look at its primitive elements - it is still very complex. For such complexity to form spontaneously, many things have to be in the right place at the right time. What are the odds? The odds are $BIGNUM.
The problem with this argument is that life does not have to begin with something that complex. The start needs to be much more simple, such that the probabilities are in line with reality.
- This video shows how primitive life can form - they grow, they replicate, they eat each other, they evolve.
- Richard Dawkins on probabilities
Formation of aminoacids
The Miller-Urey experiment shows how aminoacids can form out of anorganic chemistry, given certain conditions. Whoa! not so fast!
- Oxygen issues - aminoacids could not have formed and persist, because the presence of oxygen in the atmosphere would destroy them before they could turn into something viable.
- This does not imply that they could not form. In fact, there were historical periods in which there was no oxygen in the atmosphere - thus favorable conditions for the formation of aminoacids could have been there.
- Water is a stable compound, the oxygen in it is tied to the hydrogen and it will not oxidize whatever particles are encapsulated in a drop of water.
- The right conditions - the experiment requires tweaked parameters of the environment, such as: heating, water cooler, electrical discharges
- The planet is a big place and there is room for a lot of variation in the environments. Volcanic lakes, underwater thermal vents, electrical discharges, underground caverns, lakes of hot water, lakes of cold water, high pressure and low pressure mediums, etc. All of this exists naturally and does not require human intervention to form.
- Chirality - how come all life is "left-handed"?
- Laevo-rotary life was forced by polarized light from the stars //Orig Life Evol Biosph. 1991;21(2):59-111.