ptolemaicastronomy
==================

Diagrams of sphere models for variably strict conditionals (Lewis
counterfactuals)

Author: Richard Zach
E-mail: rzach@ucalgary.ca
License: Released under the LaTeX Project Public License v1.3c or later
See: http://www.latex-project.org/lppl.txt

David K. Lewis (Counterfactuals, Blackwell 1973) introduced a sphere
semantics for counterfactual conditionals. He jokingly referred to the
diagrams depicting such sphere models as Ptolemaic astronomy, hence
the name of this package. It has nothing to do with Ptolemy or with
astronomy, sorry.

The macros provided in this package aid in the construction of
sphere model diagrams in the style of Lewis. The macros all make use
of TikZ.

See https://github.com/rzach/ptolemaic-astronomy