“No great discovery was ever made without a bold guess.”

Fischerisms (1944)

Referring to Luke 17:33, 'Whosoever will save his life shall lose it, and whosoever will lose his life shall find it' (the wording used by Housman).

Ben Yamen's Song of Geometry (1853)
Context: The Key! it is of wonderful construction, with its infinity of combination, and its unlimited capacity to fit every lock. … it is the great master-key which unlocks every door of knowledge and without which no discovery which deserves the name — which is law, and not isolated fact — has been or ever can be made. Fascinated by its symmetry the geometer may at times have been too exclusively engrossed with his science, forgetful of its applications; he may have exalted it into his idol and worshipped it; he may have degraded it into his toy... when he should have been hard at work with it, using it for the benefit of mankind and the glory of his Creator.

Book IV, line 702 (tr. J. D. Duff).
Pharsalia

1840s, Essays: First Series (1841), Circles

The Structure of the Universe: An Introduction to Cosmology (1949)
Context: Minkowski made a remarkable discovery concerning the Lorentz formulae. He showed that, although each observer has his own private space and private time, a public concept which is the same for all observers can be formed by combining space and time as a kind of 'distance' by multiplying it by the velocity of light, c; in other words, with any time interval we can associate a definite spatial interval, namely the distance which light can travel in empty space in that period. If, according to a particular observer, the difference in time between any two events is T, this associated spatial interval is cT. Then, if R is the space-distance between these two events, Minkowski showed that the difference of the squares of cT and R has the same value for all observers in uniform relative motion. The square root of this quantity is called the space-time interval between two events. Hence, although time and three-dimensional space depend on the observer, this new concept of space-time is the same for all observers.<!--p.64