The Darwinian Hypothesis.
1. Every kind of animal and plant tends to increase in numbers in a geometrical progression.
2. Every kind of animal and plant transmits a general likeness, with individual differences, to its offspring.
3. Past time has been practically infinite.
4. Every individual has to endure a very severe struggle for existence, owing to the tendency to geometrical increase of all kinds of animals and plants, while the total animal and vegetable population (man and his agency excepted) remains almost stationary.
5. Thus, every variation of a kind tending to save the life of the individual possessing it, or to enable it more surely to propagate its kind, will in the long run be preserved and will transmit its favorable peculiarity to some of its offspring, which peculiarity will thus become intensified till it reaches the maximum degree of utility. On the other hand, individuals presenting unfavorable peculiarities will be ruthlessly destroyed (Surviv