Bernard’s attitude is distinctly that of a positivist, and the general tone of his remarks as well as his attitude on many special points agrees with that of Comte. His conclusions regarding physiology are akin to those expressed by Comte concerning biology. Bernard excludes any metaphysical hypothesis such as the operation of a vital principle, and adheres strictly to physicochemical formulas. He accepts, however, Comte’s warning about the reduction of the higher to terms of the lower, or, in Spencerian phraseology, the explanation of the more complex by the less complex. Consequently, he carefully avoids the statement that he desires to “reduce” physiology to physics and chemistry. He makes no facile and light-hearted transition as did Spencer; on the contrary, he claims that the living has some specific quality which cannot be “reduced” to other terms, and which cannot be summed up in the formulae of physics or chemistry. The physiologist and the medical practitioner must never overlook the fact that every living being forms an organism and an individuality. The physiologist, continues Bernard, must take notice of this unity or harmony of the whole, even while he penetrates the interior to know the mechanism of each of its parts. The physicist and the chemist can ignore any notion of final causes in the facts they observe, but the physiologist must admit a harmonious finality, a harmony pre-established in the organism, whose actions form and express a unity and solidarity, since they generate one another. Life itself is _creation_; it is not capable of expression merely in physico-chemical formulae. The creative character, which is its essence, never can be so expressed. Bernard postulated an abstract, _idée directrice et créatrice_, presiding over the evolution of an organism. “_Dans tout germe vivant, il y a une idée créatrice qui se développe et se manifeste par l’organisation. Pendant toute sa durée l’être vivant reste sous l’influence de cette même force vitale, créatrice, et la mort arrive lorsqu’elle ne peut plus se réaliser. Ici comme partout, tout dérive de l’idée, qui, seule, crée et dirige_.”[12] [12] _Introduction à l’Etude de la Médécine expérimentale_, p.151 ff. The positivist spirit is again very marked in the doctrines of Berthelot (1827-1907), another very great friend of Renan, who, in addition to being a Senator, and Minister of Education and of Foreign Affairs, held the Chair of Organic Chemistry at the Collège de France. In 1886 he published his volume, Science et Philosophie, which contains some interesting and illuminating observations upon _La Science idéale et la Science positive_. Part of this, it may be noted, was written as early as 1863, in correspondence with Renan, and as a reply to a letter of his of which we shall speak presently.[13] Berthelot states his case with a clearness which merits quotation. [13] See the _Fragments_ of Renan, published 1876, pp 193-241. _Reponse de M. Berthelot_.