Since we think we understand when we know the explanation, and there are four types of explanation (one, what it is to be a thing; one, that if certain things hold it is necessary that this does; another, what initiated the change; and fourth, the aim), all these are proved through the middle term.
What we see in history is not a transformation, a passing of one race into another, but entirely new and perfect creations, which the ever-youthful productivity of nature sends forth from the invisible realm of Hades.
The sceptic will say, 'It may well be true that this system of equations is reasonable from a logical standpoint, but this does not prove that it corresponds to nature.' You are right, dear sceptic. Experience alone can decide on truth.
Invention breeds invention. No sooner is the electric telegraph devised than gutta-percha, the very material it requires, is found. The aeronaut is provided with gun-cotton, the very fuel he wants for his balloon.
Evolution is the law of policies: Darwin said it, Socrates endorsed it, Cuvier proved it and established it for all time in his paper on The Survival of the Fittest. These are illustrious names, this is a mighty doctrine: nothing can ever remove it from its firm base, nothing dissolve it, but evolution.
PROBOSCIS, n. The rudimentary organ of an elephant which serves him in place of the knife-and-fork that Evolution has as yet denied him. For purposes of humor it is popularly called a trunk.
What opposite discoveries we have seen! (Signs of true genius, and of empty pockets.) One makes new noses, one a guillotine, One breaks your bones, one sets them in their sockets; But vaccination certainly has been A kind antithesis to Congreve's rockets.
Marxism: The theory that all the important things in history are rooted in an economic motive, that history is a science, a science of the search for food.
Science is a wonderful thing if one does not have to earn one's living at it. One should earn one's living by work of which one is sure one is capable. Only when we do not have to be accountable to anybody can we find joy in scientific endeavor.
Doctor Johnson said, that in sickness there were three things that were material; the physician, the disease, and the patient: and if any two of these joined, then they get the victory; for, Ne Hercules quidem contra duos [Not even Hercules himself is a match for two]. If the physician and the patient join, then down goes the disease; for then the patient recovers: if the physician and the disease join, that is a strong disease; and the physician mistaking the cure, then down goes the patient: if the patient and the disease join, then down goes the physician; for he is discredited.
When I was fourteen years old, I was amazed at how unintelligent my father was. By the time I turned twenty-one, I was astounded how much he had learned in the last seven years.
I was sitting in a chair in the patent office at Bern when all of a sudden a thought occurred to me: "If a person falls freely he will not feel his own weight." I was startled. This simple thought made a deep impression on me. It impelled me toward a theory of gravitation.