But it is to the physicists of the 19th century, and especially to Joule, whose experimental results were published in 1843-1849, that we practically owe the most notable advance that has been made in the development of the subject - namely, the establishment of the principle of the conservation of energy (see Energetics and Energy).
Mill, but differed from him in many particulars, and had as distinctive features the treatment of the doctrine of the conservation of energy in connexion with causation and the detailed application of the principles of logic to the various sciences.
Julius Thomsen was the first investigator who deliberately adopted the principle of the conservation of energy as the basis of a thermochemical system.
Nor, finally, is the last defensive position of scientific determinism - the theory, namely, that the freedom of the will is incompatible with the doctrine of the conservation of energy - to be accepted without question.
It was long believed that work done against such forces was lost, and it was not till the r9th century that the energy thus transformed was traced; the conservation of energy has become the master-key to unlock the connexions in inanimate nature.
Since there must be the same conservation of energy in morals as elsewhere, the eternal reason is the divine Logos.
In this panpsychistic parallelism he was again like Leibnitz, and he developed his predecessor's view, that the conservation of energy prevents interaction, into the supposition that alongside the physical there is a parallel psychical conservation of energy.