This realist, mystical and dialectical current of thought was destined to yield its best fruits some centuries later. For the time being, in the seventeenth century, and yet more in the century that followed, the victory seemed to rest with nominalism, that is to say, with naturalism. In Italy, Leonardo da Vinci laughed at theological and speculative disputes and celebrated, not the mind, but the _eye_ of man, that is, the science of observation. The same tendency appeared in the anti-Aristotelians and naturalists, who placed the natural sciences above scholasticism. In England, the other Bacon, however slight his importance both as philosopher and naturalist, yet has much importance as the symptom and spokesman of the self-assertion of naturalism. In the _Novum Organum,_ the universal of the _for the most part_ claims its rights as against the universal of the necessary and eternal. He does not wish, however, to do away with the latter, but rather to complete it; the syllogism is insufficient, induction also is needed. Philosophy and theology are well where they are, but a science of physics is also needed; philosophic induction, which goes at a leap to first causes, must be accompanied by a gradual induction (the only one that interests the naturalist), which connects particular facts by means of laws more and more general; final causes must be banished from the study of nature, and only efficient causes admitted. _Anticipationes naturae,_ that is to say, the invasions of philosophism into the natural sciences, are to be prohibited. These utterances are far more discreet than those that have so often since been heard. [Sidenote: _The ideal of exact science and the Cartesian philosophy._]