Henry Adams,
The Education of Henry Adams — Chapter 34…
(1918)
“ A stone arrowhead is as convincing as a steam-engine. The values were as clear a hundred thousand years ago as now, and extended equally over the whole world. The motion at last became infinitely slight, but cannot be proved to have stopped. The motion of Newton’s comet at aphelion may be equally slight. To evolutionists may be left the processes of evolution; to historians the single interest is the law of reaction between force and force,—between mind and nature,—the law of progress. ”
