The wall of partition between the two separate 'objects' cannot be broken at one attack; they have to be worn away by the attrition arising from their slow movement into one another.
"John Dewey's logical theory"
Delton Thomas Howard
Trench duty was exacting and exhausting from a physical point of view alone, but to this was added the continual attrition of numbers on account of shell and rifle fire.
"The Story of the "9th King's" in France"
Enos Herbert Glynne Roberts
At last, subdued by grief, and probably his spirit having chafed itself smooth by such constant attrition, he became, to all seeming, calmer; but it was only the calm of a broken and weary heart.
"The Confessions of Harry Lorrequer, Complete"
Charles James Lever (1806-1872)