|1 At the time there was no reason to accept the theory: it was contrary to common sense and ordinary observation in all respects. The reason for its acceptance later was partly the increased accuracy of observation, which showed large problems with the old cosmology; but also, to a greater extent, the development of a quite new kind of mechanics which made the arrangement seem possible, and which made all the elements fit.|
|2 Because astrological ideas had been based on a cosmology which made the heavens different in kind from the earth, and there was now no reason to believe that they could have this kind of influence.|
|3 Because, even though it had broken down the traditional distinction between the earth and the heavens, it did not in itself threaten the distinction between mind and matter, and body and soul, which were the most important bases of religion.|
|1 Too many offspring were produced for all to survive; there would inevitably be shortages of food and resources as long as people produced as many offspring as they did.|
|2 Darwin's addition was that since there was variation among individuals and offspring resembled parents, characteristics that helped survival in the competition would spread throughout the population.|
|1 That there must be a purpose at the root of things.|
|2 (a), (d), (g) and (j) are teleological. In each case, the question is whether the explanation looks forward to what the person was trying to achieve (the telos, or end), or whether it looks back to how the result came about.|
|3 (a) and (d) are competing explanations; (b), (c) and (e) are compatible. It is important to realize that explanations of a single happening or state of affairs can be different without being in competition, and to recognize which are which. This will be significant later in the book.|
If there were a lot of seeds around, the birds with stronger beaks did well in finding food and were able to rear a great many offspring, who in turn had beaks that enabled them to do well by their own offspring. The ones with weaker, pointed beaks produced far fewer offspring and eventually died out; but on other islands, where there were more insects, they produced more offspring than the birds with the blunt beaks.
The light brown forms of the peppered moth used to be well camouflaged against the trunks of trees, and since they were not easily seen by predators they tended to survive and produce offspring better than more conspicuous moths. But when pollution changed the colour of the tree trunks they became more easily seen and caught by predators, and the ones that happened to be darker survived more readily to reproduce.
Some flowers happened to develop into forms that resembled particular insects,