of the stars which have already been mentioned. A good illustration of this fact—and one which takes us back again to the seventeenth century—is the word _law_. The Latin ‘lex’ was first applied to natural phenomena by Bacon. Later in the century _law_ was used in the same sense, but it did not then mean quite what it does to-day. The “laws of Nature” were conceived of by those who first spoke of them as present commands of God. It is noticeable that we still speak of Nature “obeying” these laws, though we really think of them now rather as abstract principles—logical deductions of our own which we have arrived at by observation and experiment. Some account of Francis Bacon’s general influence, as a writer, on our language has already been given in Chapter IV. His influence on thought was far greater, for he was in some sense the moving spirit of that intellectual revolution which began to sweep over Europe in the sixteenth century. It was a revolution comparable in many ways to the change inaugurated by Aristotle twenty centuries earlier, and there is accordingly much in Bacon’s work that reminds us of the Greek philosopher. To begin with, he was thoroughly dissatisfied with the whole _method_ of thought as he found it in his day, and, like Aristotle, he strove first of all to effect a reformation in this. Aristotle had written the _Organum_—that is to say, the “Instrument” (of Thought)—and Bacon intended his _Novum Organum_ to go one step farther. He proclaimed himself satisfied with Aristotle’s legacy—the prevailing logical system of syllogism and deduction—as far as it went. Given the “premises,” it was the correct line of further discovery. What he questioned was the Scholastic premises themselves, and he propounded accordingly a new and surer method of establishing fresh ones. It is known as the “inductive method.” This is not the place to expound Bacon’s logical system, and it will suffice that it was based on an extensive and, above all, a systematic observation of Nature herself. Aristotle had indeed (though the Schoolmen had nearly forgotten it) pointed the way to such an observation, but it was left for Bacon to try and construct a prejudice-proof system of arranging and classifying the results. These _instances_, as they were called, were, on the one hand, to be manufactured by means of _experiment_, and on the other to be arranged and weeded out according to their significance. The word _crucial_ comes to us from Bacon’s Latin phrase ‘instantia crucis’—the _crucial instance_—which, like a sign-post, decided between two rival hypotheses by proving one and disproving the other; and it may be said that he endeavoured, but failed, to alter the meaning of _axiom_ itself from “a self-evident proposition” to “a proposition established by the method of experimental induction”.