“If heat were the affecting force, direct indications of its presence could be found which would not make use of geometry as an indirect method. …direct evidence for the presence of heat is based on the fact that it affects different materials in different ways. …The forces… which we have introduced… have two properties: (a) They affect all materials in the same way. (b) There are no insulating [or isolating] walls. …the definition of the insulating wall may be added here: it is a covering made of any kind of material which does not act upon the enclosed object with forces having property a. Let us call the forces which have the properties a and b universal forces; all other forces are called differential forces. Then it can be said that differential forces, but not universal forces, are directly demonstrable.”

— Hans Reichenbach

The Philosophy of Space and Time (1928, tr. 1957)

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Hans Reichenbach 41

American philosopher 1891–1953

Ken Kern American writer

The Owner Built Home: A How-to-do-it Book (1972)

“Clay masonry, like concrete, is a "plastic" material that permits the pouring in situ of large monoliths of any shape or form, with certain limitations and by using special methods. Its economical possibilities when used in walls of popular housing, its excellent heat and sound insulation, as well as its aesthetic possibilities, should not be underestimated. Its resistance and durability can be substantially improved by using modern techniques and methods, for example, admixture of small amounts of Portland cement in accordance with granulometric investigation, petrographic composition, and rheological behaviour of all constituents.”

Eduardo Torroja (1899–1961) Spanish architect

Philosophy of Structures (1958)

“Art and Science are two different streams which rise from the same creative force and flow into the same ocean of the common culture, but the currents of these two streams flow in different directions.”

Naum Gabo (1890–1977) Russian sculptor

Quote of Naum Gabo (1957), as cited in: Gabo: Construction, Sculpture, Paintings, Drawings, Engravings. p. 164.
1936 - 1977

“Let the letters a b c denote the three angular points of a rectilineal triangle. If the point did move continuously over the lines ab, bc, ca, that is, over the perimeter of the figure, it would be necessary for it to move at the point b in the direction ab, and also at the same point b in the direction bc. These motions being diverse, they cannot be simultaneous. There-fore, the moment of presence of the movable point at vertex b, considered as moving in the direction ab, is different from the moment of presence of the movable point at the same vertex b, considered as moving in the same direction bc. But between two moments there is time; therefore, the movable point is present at point b for some time, that is, it rests. Therefore it does not move continuously, which is contrary to the assumption. The same demonstration is valid for motion over any right lines including an assignable angle. Hence a body does not change its direction in continuous motion except by following a line no part of which is straight, that is, a curve, as Leibnitz maintained.”

Immanuel Kant (1724–1804) German philosopher

Kant's Inaugural Dissertation (1770), Section III On The Principles Of The Form Of The Sensible World

“I have… attempted to throw some new light on the general properties of matter in other forms: and on the doctrine of heat, which is materially concerned in them; and to deduce some useful conclusions from a comparison of various experiments on the elasticity of steam, on evaporation, and on the indications of hygrometers.”

Thomas Young (scientist) (1773–1829) English polymath

Preface
A Course of Lectures on Natural Philosophy and the Mechanical Arts (1807)

“There are two general Methods made use of in the Mathematicks, viz. Synthesis and Analysis, which we shall explain, after having acquainted the Reader, that the Method we make use of to resolve a Mathematical Problem, is called Zetetick; and that that Method which determines when, and by what way, and how many different ways a Problem may be resolved, is called Poristick. But in treating of Methods, we will first premise, that in general, a Method is the Art of disposing a Train of Arguments or Consequences in a right Order, either to discover the Truth of a Theorem, which we would find out, or to demonstrate it to others, when found.”

Jacques Ozanam (1640–1718) French mathematician

Source: A Mathematical Dictionary: Or; A Compendious Explication of All Mathematical Terms, 1702, p. 26

“To say that only those businesses affected with a public interest may be regulated is but another way of stating that all those businesses which may be regulated are affected with a public interest.”

Harlan F. Stone (1872–1946) United States federal judge

Tyson and Brother v. Banton, 273 U.S. 418, 451 (1927).

“There is not one who speaks of us in our presence as he does in our absence," wrote Pascal. "All affection is based on this mutual deception, and few friendships would survive if we knew what our friends were saying of us behind our backs.”

André Maurois (1885–1967) French writer

Un Art de Vivre (The Art of Living) (1939), The Art of Friendship

“This consideration must alter the form of our proposed inquiry; for the question being thus at least partly decided, since it is ascertained that we have rays of heat which give no light, it can only become a subject of inquiry whether some of these heat-making rays may not have a power of rendering objects visible, superadded to their now already established power of heating bodies. This being the case, it is evident that the onus probandi [burden of proof] ought to lie with those who are willing to establish such an hypothesis, for it does not appear that Nature is in the habit of using one and the same mechanism with any two of our senses. Witness the vibration of air that makes sound, the effluvia that occasion smells, the particles that produce taste, the resistance or repulsive powers that affect the touch—all these are evidently suited to their respective organs of sense.”

William Herschel (1738–1822) German-born British astronomer, technical expert, and composer

Source: Sir William Herschel: His Life and Works (1880), Ch.4 "Life and Works" on his discovery of the infrared.

“Both the law of inertia and the law of gravitation contain a numerical factor or a constant belonging to matter, which is called mass. We have thus two definitions of mass; one by the law of inertia: mass is the ratio between force and acceleration. We may call the mass thus defined the inertial or passive mass, as it is a measure of the resistance offered by matter to a force acting on it. The second is defined by the law of gravitation, and might be called the gravitational or active mass, being a measure of the force exerted by one material body on another. The fact that these two constants or coefficients are the same is, in Newton's system, to be considered as a most remarkable accidental coincidence and was decidedly felt as such by Newton himself. He made experiments to determine the equality of the two masses by swinging a pendulum, of which the bob was hollow and could be filled up with different materials. The force acting on the pendulum is proportional to its active mass, its inertia is proportional to its passive mass, so that the period will depend on the ratio of the passive and the active mass. Consequently the fact that the period of all these different pendulums was the same, proves that this ratio is a constant, and can be made equal to unity by a suitable choice of units, i. e., the inertial and the gravitational mass are the same. These experiments have been repeated in the nineteenth century by Bessel, and in our own times by Eötvös and Zeeman, and the identity of the inertial and the gravitational mass is one of the best ascertained empirical facts in physics-perhaps the best. It follows that the so-called fictitious forces introduced by a motion of the body of reference, such as a rotation, are indistinguishable from real forces…. In Einstein's general theory of relativity there is also no formal theoretical difference, as there was in Newton's system…. the equality of inertial and gravitational mass is no longer an accidental coincidence, but a necessity.”

Willem de Sitter (1872–1934) Dutch cosmologist

p, 125
"The Astronomical Aspect of the Theory of Relativity" (1933)

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