Even science admits that accidents account for many deaths of individuals in a species, evolutionary scientists have proved that many traits and ancestral propensities do not enable the individual to withstand factors in the surroundings in which he lives, such as the struggle for survival that particularly marks the life and death of the animals. Of course, what may be called chance or accident results in many deaths of individuals otherwise well fitted to survive, but if we consider that this phenomenon goes on continuously over long stretches of time, we see that at some point a genetic favoritism will begin to emerge.

Herbert Spencer labeled this process the “survival of the fittest,” and though the term may not be scientifically correct in the case of any given species in any one year, when we view that the battle is going on constantly, during the entire duration of each species, we cannot doubt that generally speaking those which survive are among the fittest. The fight for survival is so strong and so perpetual that the most minior weakness in any sense organ and any physical weakness will almost surely, at one time or another, be fatal.

This continual weeding out of the less fit, in every generation will effect two separate consequences, which require to be clearly distinguished. The first of the two is the conservation of each species in the broadest state of adaption to the circumstances of its environment. As long as these circumstances are unaltered, the consequence of natural selection is to keep each well-adapted species unchanged.

The second of these conditions occurs whenever the conditions change. The most suited will adapt more successfully, and the typical process of natural selection will evolve more quickly, according to the conditions. This process will eventually bring about complete adjustment to the new conditions. Some scientists accept pure probability, but observe that the process of natural selection in weeding out the genetically weaker and thus keeping every species in the fullest state of adaptation.

The issue of natural selection and survival of the fittest does not play out significantly in the contemporary debate between the proponents of evolution theory, intelligent design theory, and creation theory. In the evolution, intelligent design, creationism debate the matter of natural selection is nearly a moot point, given that evolution theory and intelligent design theory are in reasonable accord on the matter, while creation theory denies it completely. There is a great deal of disagreement on this evidenced in the evolution creationism debate, most unusual of which is an Oprah Winfrey creationism controversy.