著者

夏目 賢一

出版者

日本科学史学会

雑誌

科学史研究. 第II期 (ISSN:00227692)

巻号頁・発行日

vol.49, no.255, pp.152-162, 2010-09-24

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Michael Faraday introduced the idea of contiguous particles in order to explain the induction phenomena of electricity in 1837, thus denying the action-at-a-distance theory. However, he could not completely eliminate the possibility of action at a distance among particles, because he did not sufficiently consider rarefied air which could transmit electricity. He therefore had to assume the action at an insensible distance to account for the electric transmission in rarefied air. When he published his theory of induction, Faraday stated to consider the criterion of contact of particles only for a sensible distance, not discussing the action at an insensible distance. This idea of insensible distance came from the discussion of insensible distance stemmed from a similar argument in British empiricism, especially from the Scottish common-sense school tradition, e.g. John Robison and Thomas Thomson. They divided the qualities of matters into primary and secondary by invoking human senses as suitable criteria. While primary qualities were measurable quantities in mechanics, the secondary qualities consisted of primary qualities. Under the strong influence of Newtonian mechanics, these primary qualities included attraction and repulsion like universal gravity. Therefore it was not problematic to assume action at an insensible distance when the matters seemed to contact each other. Therefore, assuming action at an insensible distance was acceptable in the case of bodies contacting each other. This understanding led Faraday to the idea of contiguous particle.