Another contrast which singles out science from among the European movements of the sixteenth and seventeenth centuries, is its universality. Modern science was born in Europe, but its home is the whole world. In the last two centuries there has been a long and confused impact of Western modes upon the civilisation of Asia. The wise men of the East have been puzzling, and are puzzling, as to what may be the regulative secret of life which can be passed from West to East without the wanton destruction of their own inheritance which they so rightly prize. More and more it is becoming evident that what the West can most readily give to the East is its science and its scientific outlook. This is transferable from country to country, and from race to race, wherever there is a rational society. In this course of lectures I shall not discuss the details of scientific discovery. My theme is the energising of a state of mind in the modern world, its broad generalisations, and its impact upon other spiritual forces. There are two ways of reading history, forwards and backwards. In the history of thought, we require both methods. A climate of opinion—to use the happy phrase of a seventeenth century writer—requires for its understanding the consideration of its antecedents and its issues. Accordingly in this lecture I shall consider some of the antecedents of our modern approach to the investigation of nature. In the first place, there can be no living science unless there is a widespread instinctive conviction in the existence of an _Order of Things_, and, in particular, of an _Order of Nature_. I have used the word _instinctive_ advisedly. It does not matter what men say in words, so long as their activities are controlled by settled instincts. The words may ultimately destroy the instincts. But until this has occurred, words do not count. This remark is important in respect to the history of scientific thought. For we shall find that since the time of Hume, the fashionable scientific philosophy has been such as to deny the rationality of science. This conclusion lies upon the surface of Hume’s philosophy. Take, for example, the following passage from Section IV of his _Inquiry Concerning Human Understanding_: “In a word, then, every effect is a distinct event from its cause. It could not, therefore, be discovered in the cause; and the first invention or conception of it, _à priori_, must be entirely arbitrary.” If the cause in itself discloses no information as to the effect, so that the first invention of it must be _entirely_ arbitrary, it follows at once that science is impossible, except in the sense of establishing _entirely arbitrary_ connections which are not warranted by anything intrinsic to the natures either of causes or effects. Some variant of Hume’s philosophy has generally prevailed among men of science. But scientific faith has risen to the occasion, and has tacitly removed the philosophic mountain.