On Our Knowledge of the Causes of the Phenomena of Organic Nature: Being Six Lectures to Working Men, Delivered at the Museum of Practical GeologyR. Hardwicke, 1863 - 156 oldal First Edition of these lectures popularizing the content and implications of Darwin's Origin of Species. |
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animalcules animals apples asexual Atavism beak birds body bones called carbonic acid causes character common conclusion condition of organic conditions of existence constantly course creatures crustacean curious Darwin's hypothesis deposited developed domesticated pigeons earth endeavour enormous evidence experiments extent extinct fact field mice fingers and five forms gun-cotton hard and green Horse infusion inorganic world kind Lake of Killarney Lamarck larvæ layer lecture legs living male means modification muscles naturalists notice offspring organic matter organic nature origin Origin of Species particle peculiarity perfectly perpetuation phenomena of organic physiological plant Porpoise Pouter present primitive stock primitive type produced question races record reproduction result Rock Pigeon rocks seeds selective breeding sheep skeleton sort species spontaneous structure substance suppose surface T. H. HUXLEY tendency thing tion toes variation varieties vary vegetable whole wild
Népszerű szakaszok
50. oldal - The method of scientific investigation is nothing but the expression of the necessary mode of working of the human mind.
60. oldal - Laplace in their endeavours to discover and define the causes of the movements of the heavenly bodies, as you, with your own common sense, would employ to detect a burglar. The only difference is, that the nature of the inquiry being more abstruse, every step has to be most carefully watched, so that there may not be a single crack of flaw in your hypothesis.
147. oldal - But a race of dumb men, deprived of all communication with those who could speak, would be little indeed removed from the brutes. And the moral and intellectual difference between them and ourselves would be practically infinite, though the naturalist should not be able to find a single shadow of even specific structural difference.
98. oldal - ... course. And, lastly, the dispositions and voices of the birds may vary. Thus the case of the pigeons shows you that there is hardly a single particular — whether of instinct, or habit, or bony structure, or of plumage — of either the internal economy or the external shape, in which some variation or change may not take place, which, by selective breeding, may become perpetuated, and form the foundation of, and give rise to, a new race.
61. oldal - ... hypothesis. But I need not tell you that there is an enormous difference in the value of the two hypotheses. That one which is based on sound scientific knowledge is sure to have a corresponding value; and that which is a mere hasty random guess is likely to have but little value. Every great step in our progress in discovering causes has been made in exactly the same way as that which I have detailed to you. A person observing the occurrence of certain facts and phenomena asks, naturally enough,...
59. oldal - Well, we will suppose that your journey is successful, and that by good luck you meet with a policeman ; that eventually the burglar is found with your property on his person, and the marks correspond to his hand and to his boots. Probably any jury would consider those facts a very good experimental verification of your hypothesis, touching the cause of the abnormal phenomena observed in your parlor, and would act accordingly. Now, in this supposititious case, I have taken phenomena of a very common...
58. oldal - My good friend, you are going on a great deal too fast. How do you know that the man who really made the marks took the spoons? It might have been a monkey that took them, and the man may have merely looked in afterwards.
62. oldal - Having granted that the inquiry is a proper one, and having determined on the nature of the methods we are to pursue and which only can lead to success, I must now turn to the consideration of our knowledge of the nature of the processes which have resulted in the present condition of organic nature. Here, let me say at once, lest some of you misunderstand me, that I have extremely little to report. The question of how the present condition of organic nature came about, resolves itself into two questions....
57. oldal - ... and that is what constitutes your hypothesis - that the man who made the marks outside and on the window-sill, opened the window, got into the room, and stole your tea-pot and spoons. You have now arrived at a vera causa; - you have assumed a cause which, it is plain, is competent to produce all the phenomena you have observed. You can explain all these phenomena only by the hypothesis of a thief. But that is a hypothetical conclusion, of the justice of which you have no absolute proof at all;...
131. oldal - ... called Atavism and Variability, with the Conditions of Existence ; or, in other words •—given the existence of organic matter, its tendency to transmit its properties, and its tendency occasionally to vary ; and, lastly, given the conditions of existence by which organic matter is surrounded — that these put together are the causes of the present and of the past conditions of Organic Nature.