“For many centuries before modern science, and for the first two and a half centuries of modern science, the division of reality into matter and light seemed self-evident. …As long as the separation between the massive and the massless persisted, a unified description of the physical world could not be achieved.”
Source: The Lightness of Being – Mass, Ether and the Unification of Forces (2008), Ch. 1, p. 9.
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Frank Wilczek 49
physicist 1951Related quotes

Il est certain que pendant le seizième siècle, dans les années qui le précédèrent et le suivirent, l'empoisonnement était arrivé à une perfection inconnue à la chimie moderne et que l'histoire a constatée. L'Italie, berceau des sciences modernes, fut, à cette époque, inventrice et maîtresse de ces secrets dont plusieurs se perdirent.
Source: About Catherine de' Medici (1842), Part II: The Ruggieri's Secret, Ch. II: Schemes Against Schemes.
Robert Grosseteste and the Origins of Experimental Science 1100-1700 (1953)
Karl Pearson made similar division of the sciences into abstract and concrete
Source: Classification and indexing in science (1958), Other Chapters, p. 154.

Speech at the Opening Ceremony of the National Conference on Science (March 1978) (exerpts)
Draft of an introduction to the Mind Matters Symposium http://diva.library.cmu.edu/Newell/mindmatters.html, 26 May 1992, Carnegie Mellon University Archives http://diva.library.cmu.edu/Newell/biography.html

Remarks after the Solvay Conference (1927)
Context: I consider those developments in physics during the last decades which have shown how problematical such concepts as "objective" and "subjective" are, a great liberation of thought. The whole thing started with the theory of relativity. In the past, the statement that two events are simultaneous was considered an objective assertion, one that could be communicated quite simply and that was open to verification by any observer. Today we know that 'simultaneity' contains a subjective element, inasmuch as two events that appear simultaneous to an observer at rest are not necessarily simultaneous to an observer in motion. However, the relativistic description is also objective inasmuch as every observer can deduce by calculation what the other observer will perceive or has perceived. For all that, we have come a long way from the classical ideal of objective descriptions.
In quantum mechanics the departure from this ideal has been even more radical. We can still use the objectifying language of classical physics to make statements about observable facts. For instance, we can say that a photographic plate has been blackened, or that cloud droplets have formed. But we can say nothing about the atoms themselves. And what predictions we base on such findings depend on the way we pose our experimental question, and here the observer has freedom of choice. Naturally, it still makes no difference whether the observer is a man, an animal, or a piece of apparatus, but it is no longer possible to make predictions without reference to the observer or the means of observation. To that extent, every physical process may be said to have objective and subjective features. The objective world of nineteenth-century science was, as we know today, an ideal, limiting case, but not the whole reality. Admittedly, even in our future encounters with reality we shall have to distinguish between the objective and the subjective side, to make a division between the two. But the location of the separation may depend on the way things are looked at; to a certain extent it can be chosen at will. Hence I can quite understand why we cannot speak about the content of religion in an objectifying language. The fact that different religions try to express this content in quite distinct spiritual forms is no real objection. Perhaps we ought to look upon these different forms as complementary descriptions which, though they exclude one another, are needed to convey the rich possibilities flowing from man's relationship with the central order.

Source: The systems view of the world (1996), p. 8 as cited in: Martha C. Beck (2013) "Contemporary Systems Sciences, Implications for the Nature and Value of Religion, the Five Principles of Pancasila, and the Five Pillars of Islam," Dialogue and Universalism-E Volume 4, Number 1/2013. p. 3 ( online http://www.emporia.edu/~cbrown/dnue/documents/vol04.no01.2013/Vol04.01.Beck.pdf).