For this thread consider the smallest unit of life to be a breeding population.
As long as some some of the breeding population survive and it produces offspring, then life has succeeded.
Every breeding population has some advantageous mutations, as evidenced by those that survive and breed better than others.
Every breeding population has some disadvantageous mutations, as evidenced by those that don't survive and reproduce or do so marginally with little input to the gene pool.
Every breeding population has some neutral mutations, as evidenced by apparent lack of mutation that heither help nor hinder the population from breeding.
Every breeding population is subject to stochastic events that have nothing to do with fitness, but result in random chance altering the makeup of the breeding pool available for reproduction. (Genetic Drift)