gt; who have grown up with clocks and schedules.
&gt;
&gt; In mathematics, consider the concept of "number", whose definition
&gt; has gone through many twists and turns in mathematics books over the
&gt; past 2500 years and took even more radical twists and turns during
&gt; the 20th century, especially in the latter half with all of the many
&gt; different definitions that have cropped up in computer systems.
&gt;
&gt; I was recently looking at a book about SQL (the O'Reilly book
&gt; _SQL in a Nutshell_)