Except by contact, is inconceivable; and they reduce every form of causation to the efficient cause, which implies the communication of motion from one body to another.
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.
While he regards association as lying at the basis of all knowledge, he does not think it sufficient, and objects to Hume that he does not account for necessity, nor for substance and causation as known in the sciences.
The third consideration is the degree to which we apprehend that endless chain of causation inevitably demanded by reason, in which each phenomenon comprehended, and therefore man's every action, must have its definite place as a result of what has gone before and as a cause of what will follow.
It should be noted that this theory of Causation entirely denies the doctrine of Uniformity in Nature, so far as the human mind is concerned.
The further question whether the voluntary acts for which a man is ordinarily held responsible are really the outcome of his freedom of choice, is barely touched upon, and most of the problems which surround the attempt to distinguish human agency from natural and necessary causation and caprice or chance are left unsolved.
To James Matthews Duncan (1826-1890) we chiefly owe a saner and broader comprehension of the relative importance of the local and the general conditions which enter into the causation of uterine and ovarian disorders.
On the other hand, not a few disorders proved to be alien to classes to which narrower views of causation had referred them; of such are tabes dorsalis, neuritis, infantile palsy or tetanus, now removed from the category of primary nervous diseases and placed in one or other of the class of infections; or, conversely, certain forms of disease of the joints are now regarded with some certainty as members of more than one series of diseases chiefly manifest in the nervous system.
Of late years enormous impulse has been given to our knowledge of the causation of disease by microbes, through the works of Gaspard, who injected putrid matter into the veins of a living animal; by Villemin, who discovered that tuberculosis is infective; by Davaine; and especially by Pasteur, Koch and others too numerous to mention, who have worked, and are still working, at the microbic causation of disease with marvellous success.
Trace out the clue of causation to the end, says Hegel in effect, and it introduces you, not to a single first cause beyond nature, but to the totality of natural process - a substance, as it were, in which all causes inhere.