Quotessence
Home / Quotes / Quote by Leon Croizat

Quote by Leon Croizat

“Let us suppose that we have laid on the table... [a] piece of glass... and let us homologize this glass to a whole order of plants or birds. Let us hit this glass a blow in such a manner as but to crack it up. The sectors circumscribed by cracks following the first blow may here be understood to represent families. Continuing, we may crack the glass into genera, species and subspecies to the point of finally having the upper right hand corner a piece about 4 inches square representing a sub-species.”

Quote by Leon Croizat

Author

Leon Croizat

Leon Croizat was a French botanist born on July 16, 1894, and died on November 30, 1982. He is known for his research in plant taxonomy, particularly his contributions to plant geography and systematics. more

You May Also Like

“I am much occupied with the investigation of the physical causes [of motions in the Solar System]. My aim in this is to show that the celestial machine is to be likened not to a divine organism but rather to a clockwork ... insofar as nearly all the manifold movements are carried out by means of a single, quite simple magnetic force. This physical conception is to be presented through calculation and geometry.”

“I know Teddy Kennedy had fun at the Democratic convention when he said that I said that trees and vegetation caused 80 percent of the air pollution in this country. ... Well, now he was a little wrong about what I said. I didn't say 80 percent. I said 92 percent-93 percent, pardon me. And I didn't say air pollution, I said oxides of nitrogen. Growing and decaying vegetation in this land are responsible for 93 percent of the oxides of nitrogen. ... If we are totally successful and can eliminate all the manmade oxides of nitrogen, we'll still have 93 percent as much as we have in the air today.”

“If two or more instances of the phenomenon under investigation have only one circumstance in common, the circumstance in which alone all the instances agree is the cause (or effect) of the given phenomenon.”

“In the patient who succumbed, the cause of death was evidently something which was not found in the patient who recovered; this something we must determine, and then we can act on the phenomena or recognize and foresee them accurately. But not by statistics shall we succeed in this; never have statistics taught anything, and never can they teach anything about the nature of the phenomenon.”

“Proof that a given condition always precedes or accompanies a phenomenon does not warrant concluding with certainty that a given condition is the immediate cause of that phenomenon. It must still be established that when this condition is removed, the phenomen will no longer appear.”

“The cause, then, philosophically speaking, is the sum total of the conditions, positive and negative, taken together; the whole of the contingencies of every description, which being realized, the consequent invariably follows.”