It is not always the magnitude of the differences observed between species that must determine specific distinctions, but the constant preservation of those differences in reproduction.

The facts of variability, of the struggle for existence, of adaptation to conditions, were notorious enough; but none of us had suspected that the road to the heart of the species problem lay through them,...

The secrets of evolution are death and time—the deaths of enormous numbers of lifeforms that were imperfectly adapted to the environment; and time for a long succession of small mutations.

More about the selection theory: Jerne meant that the Socratic idea of learning was a fitting analogy for ‘the logical basis of the selective theories of antibody formation’: Can the truth (the capability to synthesize...

It wasn’t torpor that kept her – she was often restless to the point of irritability. She simply liked to feel that she was prevented from leaving, that she was needed.

Things exist either because they have recently come into existence or because they have qualities that made them unlikely to be destroyed in the past.

Life on earth evolved gradually beginning with one primitive life form – perhaps a self-replicating molecule – that lived more than 3.5 billion years ago; it then branched out over time, throwing off many new...

They believe civilization weakens natural selection. They do nature’s work so that we do not become a soft race.

Evidently neither cats nor dogs, nor other animals that listen to human music, were constituted for the appreciation of it, for it is not of the slightest use to them in the struggle for existence....

Natural selection eliminates and maybe maintains, but it doesn’t create… Neo-Darwinists say that new species emerge when mutations occur and modify an organism. I was taught over and over again that the accumulation of random...

The Christians who engaged in infamous persecutions and shameful inquisitions were not evil men but misguided men. The churchmen who felt they had an edict from God to withstand the progress of science, whether in...

It is a strange fact, incidentally, that religious apologists love the anthropic principle. For some reason that makes no sense at all, they think it supports their case. Precisely the opposite is true. The anthropic...

Natural selection is not the wind which propels the vessel, but the rudder which, by friction, now on this side and now on that, shapes the course.

It is therefore scientifically correct to say that ‘natural selection has been proved to be an agent of evolutionary change’ – we can, in fact, prove it by doing. But it is totally illegitimate to...

If theft is advantageous to everyone who succeeds at it, and adultery is a good strategy, at least for males, for increasing presence in the gene pool, why do we feel they are wrong? Shouldn’t...

[E]very major religion today is a winner in the Darwinian struggle waged among cultures, and none ever flourished by tolerating its rivals.

The most essential prediction of Darwinism is that, given an astronomical number of chances, unintelligent processes can make seemingly-designed systems, ones of the complexity of those found in the cell. ID specifically denies this, predicting...

The embryological record is almost always abbreviated in accordance with the tendency of nature (to be explained on the principle of survival of the fittest) to attain her needs by the easiest means.

Natural selection is not only a parsimonious, plausible and elegant solution; it is the only workable alternative to chance that has ever been suggested. Intelligent design suffers from exactly the same objection as chance. It...

In the distant future I see open fields for far more important researches. Psychology will be based on a new foundation, that of the necessary acquirement of each mental power and capacity by gradation. Light...

I’m an Atheist. I don’t believe in God, Gods, Godlets or any sort of higher power beyond the universe itself, which seems quite high and powerful enough to me. I don’t believe in life after...

That natural selection can produce changes within a type is disputed by no one, not even the staunchest creationist. But that it can transform one species into another — that, in fact, has never been...

A totally blind process can by definition lead to anything; it can even lead to vision itself.

It looks as if the offspring have eyes so that they can see well (bad, teleological, backward causation), but that’s an illusion. The offspring have eyes because their parents’ eyes did see well (good, ordinary,...

Indeed, not all attacks—especially the bitter and ridiculing kind leveled at Darwin—are offered in good faith, but for practical purposes it is good policy to assume that they are.

Nothing in biology makes sense except in the light of evolution.

One general law, leading to the advancement of all organic beings, namely, multiply, vary, let the strongest live and the weakest die.

In 1867, George Campbell, Duke of Argyll, had published The Reign of Law, a book that Darwin found deeply annoying. A supporter of Richard Owen, Campbell argued that while evolution (or “Development”) might be observable...

Might one not say that in the chance combination of nature’s production, since only those endowed with certain relations of suitability could survive, it is no cause for wonder that this suitability is found in...

Even today a good many distinguished minds seem unable to accept or even to understand that from a source of noise natural selection alone and unaided could have drawn all the music of the biosphere....

What are the chances that we will one day discover that DNA has absolutely nothing to do with inheritance? They are effectively zero.

I am quite sure that our views on evolution would be very different had biologists studied genetics and natural selection before and not after most of them were convinced that evolution had occurred.

Nature’s stern discipline enjoins mutual help at least as often as warfare. The fittest may also be the gentlest.

To suppose that the eye with all its inimitable contrivances for adjusting the focus to different distances, for admitting different amounts of light, and for the correction of spherical and chromatic aberration, could have been...

Historians will have to face the fact that natural selection determined the evolution of cultures in the same manner as it did that of species.

When one ponders on the tremendous journey of evolution over the past three billion years or so, the prodigious wealth of structures it has engendered, and the extraordinarily effective teleonomic performances of living beings from...

It will be noticed that the fundamental theorem proved above bears some remarkable resemblances to the second law of thermodynamics. Both are properties of populations, or aggregates, true irrespective of the nature of the units...

{On to contributions to evolutionary biology of 18th century French scientist, Georges-Louis Leclerc, Comte de Buffon}He was not an evolutionary biologist, yet he was the father of evolutionism. He was the first person to discuss...

Perhaps the most legitimately dispiriting thing about reciprocal altruism is that it is a misnomer. Whereas with kin selection the “goal” of our genes is to actually help another organism, with reciprocal altruism the goal...

The expression often used by Mr. Herbert Spencer of the Survival of the Fittest is more accurate, and is sometimes equally convenient.

It is essential for genetic material to be able to make exact copies of itself; otherwise growth would produce disorder, life could not originate, and favourable forms would not be perpetuated by natural selection.

Natural selection favors the forces of psychological denial. The individual benefits as an individual from his ability to deny the truth even though society as a whole, of which he is a part, suffers. Education...

The very comprehensibility of the world points to an intelligence behind the world. Indeed, science would be impossible if our intelligence were not adapted to the intelligibility of the world. The match between our intelligence...

Evolution is an integration of matter and concomitant dissipation of motion during which the matter passes from an indefinite incoherent homogeneity to a definite coherent heterogeneity, and during which the retained motion undergoes a parallel...

Natural selection is a mechanism for generating an exceedingly high degree of improbability.

I fully agree with all that you say on the advantages of H. Spencer’s excellent expression of ‘the survival of the fittest.’ This, however, had not occurred to me till reading your letter. It is,...

Darwin called such a process artificial, as opposed to natural, selection, but from the flower’s point of view, this is a distinction without a difference: individual plants in which a trait desired by either bees...

In Paley’s famous illustration, the adaptation of all the parts of the watch to the function, or purpose, of showing the time, is held to be evidence that the watch was specially contrived to that...

When I see the moon on a clear night, I do say “blessed be” and I remind myself to be grateful to the universe that I happen to exist in such a lovely and wondrous...

…if an organised body is not in the situation and circumstances best adapted to its sustenance and propagation, then, in conceiving an indefinite variety among the individuals of that species, we must be assured, that,...