What changes when knowledge travels faster?

That time, that place

Gutenberg of Mainz was trained as a goldsmith. To make one book then, several monks copied by hand for months, and the price could rival a house.

Why this question

Printing itself was not new. China had used woodblocks for centuries, and Korea had printed books with movable metal type.

Gutenberg faced a somewhat different problem: producing thousands of alphabetic characters, all identical, quickly and cheaply.

What was found

What he solved was not one problem but a combination.

A hand mold that casts type identically. An alloy of lead, tin, and antimony — melting at low temperature and shrinking almost not at all as it cools, so letterforms hold. An oil-based ink that clings to metal. And a press adapted from the winepress. Remove any one and nothing works.

The result was speed. In the time one manuscript took, hundreds of copies appeared. Within fifty years, printed books in Europe numbered in the millions.

And one quiet, decisive change followed: two people far apart could now argue over the same page of the same edition.