Passages

William Goldbloom Bloch's The Unimaginable Mathematics of Borges' Library of Babel is not actually the book I originally intended to write about for this issue. I had never heard of this book (published in 2008; finalist for the 2008 American Association of American Publishers PROSE award in Mathematics) until about two weeks before the deadline for this column, which is somewhat surprising, given the topic. I ran across the book while wandering in a library, naturally, and when I saw the title I was forced to stop and pay attention to it. My first reaction (beyond the initial interest in the intersection of math and Borges) was to be slightly annoyed at the title, thinking ''unimaginable'' to be sloppy (Borges imagined it, you lout!) and superficial. But, in fact, the precision with which the title was chosen is part of why I made this book this column's classic for software engineers. You see, Bloch says: ''Finally, about the title of the book: why the word 'unimaginable'? By way of an answer, we note that in his sixth Meditation, Descartes makes clear the distinction between simply naming a thing and visualizing it in a clear, precise way that allows for mental manipulations.''