On Spacetime (1875-1899)

"With every simple act of thinking, something permanent, substantial, enters our soul. This substantial somewhat appears to us as a unit but (in so far as it is the expression of something extended in space and time) it seems to contain an inner manifoldness; I therefore name it ‘mind-mass’. All thinking is, accordingly, formation of new mind masses." (Bernhard Riemann," Gesammelte Mathematische Werke", 1876)

"In infinite time, in infinite matter, in infinite space, is formed a bubble organism, and that bubble lasts a while and bursts, and that bubble is Me." (Lev Tolstoy, "Anna Karenina", 1877)

"She [Nature] works with reference to no measure of time, no limit of space, and with an abundance of material not expressed by exhaustless." (John Burroughs, "Birds and Poets With Other Papers", 1884)

"Time is but the space between our memories; as soon as we cease to perceive this space, time has disappeared." (Henri-Frédéric Amiel, "Amiel's Journal", 1884)

"We may conceive our space to have everywhere a nearly uniform curvature, but that slight variations of the curvature may occur from point to point, and themselves vary with the time. These variations of the curvature with the time may produce effects which we not unnaturally attribute to physical causes independent of the geometry of our space. We might even go so far as to assign to this variation of the curvature of space 'what really happens in that phenomenon which we term the motion of matter'." (William K Clifford, Richard C Rowe & Karl Pearson,"The Common Sense of the Exact Sciences", 1885) 

"Properly speaking the world is not composed of 'things' as its elements, but colors, tones, pressures, spaces, times, in short what we ordinarily call individual sensations." (Ernst Mach, "The Science of Mechanics", 1893)

"Modern mathematics, that most astounding of intellectual creations, has projected the mind's eye through infinite time and the mind's hand into boundless space." (Nicholas M Butler, "What Knowledge is of Most Worth?", 1895)

"There are really four dimensions, three which we call the three planes of Space, and a fourth, Time. There is, however, a tendency to draw an unreal distinction between the former three dimensions and the latter, because it happens that our consciousness moves intermittently in one direction along the latter from the beginning to the end of our lives. [...] Really this is what is meant by the Fourth Dimension, though some people who talk about the Fourth Dimension do not know they mean it. It is only another way of looking at Time. There is no difference between Time and any of the three dimensions of Space except that our consciousness moves along it." (Herbert G Wells,"The Time Machine", 1895) 

"The world is chiefly a mental fact. From mind it receives the forms of time and space, the principle of causality, color, warmth, and beauty. Were there no mind, there would be no world." (John L Spalding, "Means and Ends of Education", 1895)