The divine reveals itself in the physical world.
Z. Rosenkrantz, Albert through the Looking-Glass (Jewish National and University Library, Jerusalem, 1998), quoted in Jammer, p.51.
Excerpted from Calaprice. See pp. 145 - 161.
Everyone who is seriously involved in the pursuit of science becomes convinced that a spirit is manifest in the laws of the Universe-a spirit vastly superior to that of man.... In this way the pursuit of science leads to a religious feeling of a special sort, which is indeed quite different from the religiosity of someone more naive.
— Letter to a child who asked if scientists pray, January 24, 1936; Einstein Archive 42-601
In every true searcher of Nature there is a kind of religious reverence, for he finds it impossible to imagine that he is the first to have thought out the exceedingly delicate threads that connect his perceptions.
— 1920; quoted in Moszkowski, Conversations with Einstein p. 46
I have found no better expression than "religious" for confidence in the rational nature of reality, insofar as it is accessible to human reason. Whenever this feeling is absent, science degenerates into uninspired empiricism.
Letter to Maurice Solovine, I January 1, 1951; Einstein Archive 21-174, 80-871, published in Letters to Solovine , p. 119.
When asked by an astounded atheist, if he were in fact deeply religious, Einstein replied:
Yes, you can call it that. Try and penetrate with our limited means the secrets of nature and you will find that, behind all the discernible concatenations, there remains something subtle, intangible and inexplicable. Veneration for this force beyond anything that we can comprehend is my religion. To that extent I am, in point of fact, religious.
— H. G. Kessler, The Diary of a Cosmopolitan, (London: Weidenfeld and Nicolson, 1971), p.157; quoted in Einstein and Religion by Max Jammer (Princeton University Press, 1999) pp. 39-40.
A religious person is devout in the sense that he has no doubt about the significance of those superpersonal objects and goals which neither require nor are capable of rational foundation.
— Nature 146 (1940), p. 605