“Although to penetrate into the intimate mysteries of nature and thence to learn the true causes of phenomena is not allowed to us, nevertheless it can happen that a certain fictive hypothesis may suffice for explaining many phenomena.”

A Thanksgiving Sermon (1897)
Context: Did Christ or any of his apostles add to the sum of useful knowledge? Did they say one word in favor of any science, of any art? Did they teach their fellow-men how to make a living, how to overcome the obstructions of nature, how to prevent sickness—how to protect themselves from pain, from famine, from misery and rags? Did they explain any of the phenomena of nature? Any of the facts that affect the life of man? Did they say anything in favor of investigation—of study—of thought? Did they teach the gospel of self-reliance, of industry—of honest effort? Can any farmer, mechanic, or scientist find in the New Testament one useful fact? Is there anything in the sacred book that can help the geologist, the astronomer, the biologist, the physician, the inventor—the manufacturer of any useful thing?

On the Nature of Places, a continuation of the treatise On Lines, Angles and Figures as quoted by Amelia Carolina Sparavigna, "Translation and discussion of the De Iride, a treatise on optics by Robert Grosseteste" arXiv:1211.5961v1 http://arxiv.org/abs/1211.5961 @arXiv.org, Cornell University (2012)
Context: The diligent investigator of natural phenomena can give the causes of all natural effects... by the rules and roots and foundations given from the power of geometry.

Source: "The Scientific Character of Geology," 1961, p. 454; As cited in: Alberta Research Council, ‎Research Council of Alberta (1964), Bulletin - Alberta Research Council. Vol. 15-17, p. 31

"Passages from the life of a philosopher", Appendix, p. 490
Passages from the Life of a Philosopher (1864)

We'll Never Conquer Space (1960)
Context: Our age is in many ways unique, full of events and phenomena that never occurred before and can never happen again. They distort our thinking, making us believe that what is true now will be true forever, though perhaps on a larger scale. Because we have annihilated distance on this planet, we imagine that we can do it once again. The facts are otherwise, and we see them more clearly if we forget the present and turn our minds towards the past.

Causality
Gesammelte Mathematische Werke (1876)

Attributed to Albertus Magnus in: Albertus Magnus; cited in: Morris Bishop (1968) The Middle Ages. p. 252.

The Fundamental Equations for Electromagnetic Processes in Moving Bodies (1907)

Nobel Prize Autobiography, from Les Prix Nobel. The Nobel Prizes 1980, Editor Wilhelm Odelberg, (Nobel Foundation), Stockholm (1981).