“We were making sand castles. Now we swim in the sea that swept them away”

Castles Made Of Sand
Song lyrics, Axis: Bold as Love (1967)
Variant: Castles made of sand, fall in the sea, eventually

Source: The Power-House (1916), Ch. 3 "Tells of a Midsummer Night"
Context: When all is said, we are ruled by the amateurs and the second-rate. The methods of our departments would bring any private firm to bankruptcy. The methods of Parliament — pardon me — would disgrace any board of directors. Our rulers pretend to buy expert knowledge, but they never pay the price for it that a business man would pay, and if they get it they have not the courage to use it. Where is the inducement for a man of genius to sell his brains to our insipid governors?
And yet knowledge is the only power — now as ever. A little mechanical device will wreck your navies. A new chemical combination will upset every rule of war. It is the same with our commerce. One or two minute changes might sink Britain to the level of Ecuador, or give China the key of the world's wealth. And yet we never dream that these things are possible. We think our castles of sand are the ramparts of the universe.

Source: Little Women

The World Crisis, 1911–1914 : Chapter IX (The Crisis), Churchill, Butterworth (1923), pp. 212-213.
Early career years (1898–1929)

Many Long Years Ago (1945), Pretty Halcyon Days

Source: Going Bovine

Last words, to his wife Maud (6 May 1919), as quoted in Uncovering Lives : The Uneasy Alliance of Biography and Psychology (1994) by Alan C. Elms, p. 154

Source: Dracula