“Divide et impera” is as true in algebra as in statecraft; but no less true and even more fertile is the maxim “auge et impera”.The more to do or to prove, the easier the doing or the proof.

Le paradoxe, c'est de la graine de vérité. Il suffit d'un terrain propice pour que cela germe, fleurisse et fructifie.
The paradox is the seed of truth. This germ just needs a fertile ground to flourish and bear fruit.

Ut ager quamvis fertilis sine cultura fructuosus esse non potest, sic sine doctrina animus.
A mind without instruction can no more bear fruit than can a field, however fertile, without cultivation.

A large proportion of mankind, like pigeons and partridges, on reaching maturity, having passed through a period of playfulness or promiscuity, establish what they hope and expect will be a permanent and fertile mating relationship. This we call marriage.

Bertrand, Darboux, and Glaisher have compared Cayley to Euler, alike for his range, his analytical power, and, not least, for his prolific production of new views and fertile theories. There is hardly a subject in the whole of pure mathematics at which he has not worked.

EMBALM, v.t. To cheat vegetation by locking up the gases upon which it feeds. By embalming their dead and thereby deranging the natural balance between animal and vegetable life, the Egyptians made their once fertile and populous country barren and incapable of supporting more than a meagre crew. The modern metallic burial casket is a step in the same direction, and many a dead man who ought now to be ornamenting his neighbor's lawn as a tree, or enriching his table as a bunch of radishes, is doomed to a long inutility. We shall get him after awhile if we are spared, but in the meantime the violet and rose are languishing for a nibble at his glutæus maximus.

Even the facts of science may dust the mind by their dryness, unless they are … rendered fertile by the dews of fresh and living truth. Knowledge does not come to us by details, but in flashes of light from heaven.

Everyone admits that the male is the primary efficient cause in generation, as being that in whom the species or form resides, and they further assert that his genitures emitted in coitus causes the egg both to exist and to be fertile. But how the semen of the cock produces the chick from the egg, neither the philosophers nor the physicians of yesterday or today have satisfactorily explained, or solved the problem formulated by Aristotle.

Fertile soil, level plains, easy passage across the mountains, coal, iron, and other metals imbedded in the rocks, and a stimulating climate, all shower their blessings upon man.

In general, a fact is worth more than theories in the long run. The theory stimulates, but the fact builds. The former in due time is replaced by one better but the fact remains and becomes fertile.

In nature hybrid species are usually sterile, but in science the reverse is often true. Hybrid subjects are often astonishingly fertile, whereas if a scientific discipline remains too pure it usually wilts.

It is usually not recognized that for every injurious or parasitic microbe there are dozens of beneficial ones. Without the latter, there would be no bread to eat nor wine to drink, no fertile soils and no potable waters, no clothing and no sanitation. One can visualize no form of higher life without the existence of the microbes. They are the universal scavengers. They keep in constant circulation the chemical elements which are so essential to the continuation of plant and animal life.

Modern war, even from the consideration of physical welfare, is not creative. Soldiers and civilians alike are supposed to put on mental khaki. … War means the death of that fertile war which consists of the free, restless conflict of ideas. The war which matters is that of the scientist with nature; of the farmer with the tawny desert; of … philosopher against … mob stupidity. Such war is creative. … Inventions that further life and joy; freedom; new knowledge, whether Luther Burbank’s about the breeding of fruits or Einstein's about relativity; great cathedrals and Beethoven's music: these modern mechanical war can destroy but never produce. At its most inventive height, war creates the Maxim gun, the submarine, disseminable germs of disease, life-blasting gases. Spiritually and intellectually, modern war is not creative.

Nature becomes fertile only by virtue of laws that oblige matter to organize itself into one of a number of necessarily very simple primitive forms. Because of their very simplicity, these are capable of constituting the basis for increasingly complex bodies, by the addition of organs calculated according to identical laws of possibility.

One naturally asks, what was the use of this great engine set at work ages ago to grind, furrow, and knead over, as it were, the surface of the earth? We have our answer in the fertile soil which spreads over the temperate regions of the globe. The glacier was God’s great plough.

One of the ironies of volcanoes is that they tend to produce very fertile soils, and that tends to lure people to live around them.

Perhaps the majority of paleontologists of the present time, who believe in orthogenesis, the irreversibility of evolution and the polyphyletic origin families, will assume that a short molar must keep on getting shorter, that it can never get longer and then again grow relatively shorter and therefore that Propliopithecus with its extremely short third molar and Dryopithecus its long m3 are alike excluded from ancestry of the Gorilla, in which the is a slight retrogression in length of m3. After many years reflection and constant study of the evolution of the vertebrates however, I conclude that 'orthogenesis' should mean solely that structures and races evolve in a certain direction, or toward a certain goal, only until the direction of evolution shifts toward some other goal. I believe that the 'irreversibility of evolution' means only that past changes irreversibly limit and condition future possibilities, and that, as a matter of experience, if an organ is once lost the same (homogenous) organ can be regained, although nature is fertile in substituting imitations. But this not mean, in my judgement, that if one tooth is smaller than its fellows it will in all cases continue to grow smaller.

Remind me that the most fertile lands were built by the fires of volcanoes.

Science is continually correcting what it has said. Fertile corrections... science is a ladder... poetry is a winged flight... An artistic masterpiece exists for all time... Dante does not efface Homer.

The consideration of mathematics is at the base of knowledge of the mind as it is at the base of the natural sciences, and for the same reason: the free and fertile work of thought dates from that epoch when mathematics brought to man the true norm of truth.

The Earth obey’d and straight
Op’ning her fertile womb, teem’d at a birth Innumerous living creatures, perfect forms,
Limb’d and full grown.

The hypothetical character of continual creation has been pointed out, but why is it more of a hypothesis to say that creation is taking place now than that it took place in the past? On the contrary, the hypothesis of continual creation is more fertile in that it answers more questions and yields more results, and results that are, at least in principle, observable. To push the entire question of creation into the past is to restrict science to a discussion of what happened after creation while forbidding it to examine creation itself. This is a counsel of despair to be taken only if everything else fails.

The origin of species is therefore simply the evolution of some difference—any difference at all—that prevents the production of fertile hybrids between populations under natural conditions.

The ravages committed by man subvert the relations and destroy the balance which nature had established between her organized and her inorganic creations; and she avenges herself upon the intruder, by letting loose upon her defaced provinces destructive energies hitherto kept in check by organic forces destined to be his best auxiliaries, but which he has unwisely dispersed and driven from the field of action. When the forest is gone, the great reservoir of moisture stored up in its vegetable mould is evaporated, and returns only in deluges of rain to wash away the parched dust into which that mould has been converted. The well-wooded and humid hills are turned to ridges of dry rock, which encumbers the low grounds and chokes the watercourses with its debris, and–except in countries favored with an equable distribution of rain through the seasons, and a moderate and regular inclination of surface–the whole earth, unless rescued by human art from the physical degradation to which it tends, becomes an assemblage of bald mountains, of barren, turfless hills, and of swampy and malarious plains. There are parts of Asia Minor, of Northern Africa, of Greece, and even of Alpine Europe, where the operation of causes set in action by man has brought the face of the earth to a desolation almost as complete as that of the moon; and though, within that brief space of time which we call “the historical period,” they are known to have been covered with luxuriant woods, verdant pastures, and fertile meadows, they are now too far deteriorated to be reclaimable by man, nor can they become again fitted for human use, except through great geological changes, or other mysterious influences or agencies of which we have no present knowledge, and over which we have no prospective control. The earth is fast becoming an unfit home for its noblest inhabitant, and another era of equal human crime and human improvidence, and of like duration with that through which traces of that crime and that improvidence extend, would reduce it to such a condition of impoverished productiveness, of shattered surface, of climatic excess, as to threaten the depravation, barbarism, and perhaps even extinction of the species.

The ruthless destruction of their forests by the Chinese is one of the reasons why famine and plague today hold this nation in their sinister grasp. Denudation, wherever practiced, leaves naked soil; floods and erosion follow, and when the soil is gone men must also go—and the process does not take long. The great plains of Eastern China were centuries ago transformed from forest into agricultural land. The mountain plateau of Central China have also within a few hundred years been utterly devastated of tree growth, and no attempt made at either natural or artificial reforestation. As a result, the water rushes off the naked slopes in veritable floods, gullying away the mountain sides, causing rivers to run muddy with yellow soil, and carrying enormous masses of fertile earth to the sea. Water courses have also changed; rivers become uncontrollable, and the water level of the country is lowered perceptibly. In consequence, the unfortunate people see their crops wither and die for lack of water when it is most needed.

The shrewd guess, the fertile hypothesis, the courageous leap to a tentative conclusion—these are the most valuable coin of the thinker at work.

The so-called ‘crank’ may be quite original in his ideas. … Invention, however, in the engineering sense involves originality; but not that alone, if the results are to be of value. There is imagination more or less fertile, but with it a knowledge of what has been done before, carried perhaps by the memory, together with a sense of the present or prospective needs in art or industry. Necessity is not always the mother of invention. It may be prevision.

There can be no greater issue than that of conservation in this country. Just as we must conserve our men, women and children, so we must conserve the resources of the land on which they live. We must conserve the soil so that our children shall have a land that is more and not less fertile than our fathers dwelt in. We must conserve the forests, not by disuse, but by use, making them more valuable at the same time that we use them. We must conserve the mines. Moreover, we must insure so far as possible the use of certain types of great natural resources for the benefit of the people as a whole.

These microscopic organisms form an entire world composed of species, families and varieties whose history, which has barely begun to be written, is already fertile in prospects and findings of the highest importance. The names of these organisms are very numerous and will have to be defined and in part discarded. The word microbe which has the advantage of being shorter and carrying a more general meaning, and of having been approved by my illustrious friend, M. Littré, the most competent linguist in France, is one we will adopt.

We have before us the restoration of that ancient land whose name was a synonym for abundance, prosperity, and grandeur for many generations. Records as old as those of Egypt and as well attested tell of fertile lands and teeming populations, mighty kings and warriors, sages and wise men, over periods of thousands of years. ... A land such as this is worth resuscitating. Once we have apprehended the true cause of its present desolate and abandoned condition, we are on our way to restoring it to its ancient fertility. A land which so readily responded to ancient science, and gave a return which sufficed for the maintenance of a Persian Court in all its splendor, will surely respond to the efforts of modern science and return manifold the money and talent spent on its regeneration.