Chapter X
"Modern Physical Ideas"
The development of physical science over the last twenty years has revealed phenomena which illustrate clearly the principles and method of the preceding chapters. The Newtonian scheme of dynamics has been shown to be an approximation valid only for gross matter and our gross senses. There is reasonable ground for supposing that an electro-magnetic scheme of the constitution of matter will prove far more comprehensive. But there are outstanding difficulties, notably that gravitation has so far defied all efforts to bring it into line with this scheme, and that no simple concept has yet been furnished to represent the positive electricity of experiment.
The principles of conservation of energy, momentum, and mass all become meaningless without an ether which is as much and as little a reality as matter, and then mass, energy, momentum, are quantities in the same category with force.
The constancy of the mass of a body in material dynamics, which is the whole experimental basis of that science, is replaced by the conception of all electrons of the same type (negative, possibly also positive) being identical in character.
The ether is a purely conceptual medium which, as far as theory is at present developed, is structureless except that at isolated points there exist centres at which its properties are exceptional. These centres, by their mutual motion and grouping, constitute the model of the sequence of natural phenomena.
New light is thrown on our conceptions of space and time. They are interdependent and conditioned by the phenomena which they are used to describe. The phrase "motion relative to the ether" becomes meaningless. The ether is becoming more and more clearly a concept in the mind of each observer.
Read more about this topic: The Grammar Of Science
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