Matter
Collier's New Encyclopedia (1921)
the substance of which all bodies are constituted; that of which anything is made, formed or composed; constituent elements; material or substantial part of anything; essential nature; embodiment. Body; extended substance; that which is visible or tangible to the perceptive senses; that which fills space, and of which the macrocosm of nature, and all essential bodies consists. That which possesses the properties whose existence is revealed to us by our senses; that part of the universe which is neither mind nor force-substance. We know nothing of the essential or intimate nature of matter, and are only acquainted with its existence through its essential properties, which are: Divisibility, impenetrability, porosity, compressibility; to which may be added extension and figure, which belong also to space, and form the subject of geometry. The contingent properties of matter are mobility and weight. Matter in every form is capable of being moved from one place to another; and every substance is subject to the attraction of gravitation. But motion has reference to space, and weight to the attraction of other matter. The above are the general properties of matter, on which physical investigations depend. There are, however, various other qualities belonging to particular substances, or to matter in particular states, the consideration of which is important in mechanical philosophy. Among these the principal are elasticity, fluidity, hardness, rigidity, solidity. MATTERHORN (mät'-) (in French Mont Cervin, in Italian Monte Silvio), a peak of the Alps between the Swiss canton of Valais and Piedmont, rising to the altitude of 14,705 feet. The actual peak was first scaled by Lord Francis Douglas, the Rev. C. Hudson, Hadow, and Whymper, with three guides, July 14, 1865, when the three first-named and one of the guides fell over a precipice and were killed.
What Has Changed in the Last Century
Collier's in 1921 defined matter by its sensible properties -- divisibility, impenetrability, porosity, weight -- and set it apart as "that part of the universe which is neither mind nor force-substance," while admitting "we know nothing of the essential or intimate nature of matter." That last admission has been overtaken with a vengeance. Einstein's 1905 equivalence of mass and energy dissolved the boundary between matter and "force-substance" entirely; Rutherford's nucleus showed the impenetrable atom to be mostly empty space; the positron, found in 1932, gave matter a mirror-image antimatter; and by the 1970s the Standard Model had reduced ordinary matter to quarks and leptons, with the Higgs boson confirmed at CERN in 2012. Cosmology has gone further still: the familiar matter Collier's described accounts for only about five per cent of the contents of the universe, the rest being dark matter and dark energy whose nature remains unknown.
Written for this edition, 2026.