George Berkeley
Berkeley argued that forces and gravity, as defined by Newton, constituted "occult qualities" that "expressed nothing distinctly". He held that those who posited "something unknown in a body of which they have no idea and which they call the principle of motion, are in fact simply stating that the principle of motion is unknown." Therefore, those who "affirm that active force, action, and the principle of motion are really in bodies are adopting an opinion not based on experience." Forces and gravity existed nowhere in the phenomenal world. On the other hand, if they resided in the category of "soul" or "incorporeal thing", they "do not properly belong to physics" as a matter. Berkeley thus concluded that forces lay beyond any kind of empirical observation and could not be a part of proper science. He proposed his theory of signs as a means to explain motion and matter without reference to the "occult qualities" of force and gravity.
John Ernst Worrell Keely
Burk and Scott reported their findings to Mrs Moore, who was concerned by the negative report, and also by dismissive articles in the press. It was reported on March 22, 1896 that Mrs Bloomfield Moore had arranged with Professor Wentworth Lascelles Scott of London to investigate Keely's claims of etheric force and also to examine his other inventions. It was said that "an important series of tests will be made in the presence of the scientist". Lascelles Scott was allowed to examine whatever he wanted and had complete instructions on its use from Keely. After spending a month investigating, Lascelles Scott stated to a meeting of the Franklin Institute that "Keely has demonstrated to me, in a way which is absolutely unquestionable, the existence of a force hitherto unknown."