Excursus

In earlier posts, I observed that some things that are easy to do with LaTeX are unobvious, like word count and double spacing.

There are a lot of packages for LaTeX that add a lot of extra functionality. Consider the following esoteric example. Gottlob Frege was a nineteenth century German mathematician and philosopher and arguably the first philosopher of language. While earlier philosophers had reflected on language—Plato, Aristotle, Leibniz, and Locke, to name four off the top of my head, it was Frege who established the philosophy of language as an autonomous subdiscipline of which contemporary philosophy of language is a recognizable descendant. Frege was also the founder of modern mathematical logic whose work on quantifiers was arguably the single greatest achievement in logic since the time of Aristotle. Frege’s system was roughly equivalent to first- and second-order logic with identity. While his logic is familiar, his notation is not. Here’s an example:

While strange looking and space consuming, proofs using Frege’s notation are remarkably easy and transparent (detachment, or modus ponens, literally involves detaching a branch).

Suppose you are writing a paper on Frege’s philosophy of mathematics and need to discuss Frege’s proofs and theorems as represented by his notation. You could do this in a graphics program such as Illustrator or Omnigraffle. You could try your hand at METAPOST, PSTricks, or PGF TiKZ. But there is an easier way. CTAN has a package! For more information about begriff.sty see this page on the Arche wiki. And be sure to use it in conjunction with fge a font, based on Computer Modern, designed to work with Frege’s special notation.