Frege's Theorem:
Article in the Stanford Encylcopaedia of Philosophy, entitled `Frege's
Logic, Theorem, and Foundations for Arithmetic'. Discusses the 1980
discovery of Crispin Wright that Frege's work of the Grundgesetze
can be carried out in second-order logic with Hume's principle.
http://plato.stanford.edu/entries/frege-logic/index.html
Logic and Mathematics:
Essay on the nature of logic and its relationship to the philosophy
of mathematics, written by Stephen G. Simpson.
http://www.math.psu.edu/simpson/papers/philmath/
Why Aristotelian Logic does not Work:
An essay at Abelard.org outlining an argument against Aristotelian
syllogistic. The argument focusses upon the relationship between
Aristotle's categories and his conception of being, attacking them
from an idealist position drawing upon Brouwerian intuitionism and
some Zen philosophy.
http://www.abelard.org/category/category.htm
The Troublesome Paradox:
Online version of book seeking publication by Per Lundgren. Author
attempts to argue that a consequence of Goedel's incompleteness
theorem is that we should overturn our current approach to
scientific method.
http://www.yesgoyes.com/
Logic:
An online textbook by Garth Kemerling, explaining the basic elements
of elementary logic at an undergraduate level.
http://www.philosophypages.com/lg/
Peirce's Logic:
Article in the Stanford Encyclopaedia of Philosophy, by Eric Hammer.
http://plato.stanford.edu/entries/peirce-logic/
Philosophical Logic:
Introductory article by E. J. Loewe.
http://www.dur.ac.uk/~dfl0www/modules/logic/PHILLOG.HTM
Nordic Journal of Philosophical Logic (NJPL):
Edited at Dep. of Philosophy, Univ. of Oslo, published by
Scandinavian U.P. in hard copy and on WWW. Full-text Web edition
free for personal use.
http://www.hf.uio.no/filosofi/njpl/
Symbolic Logic:
Online resources provided to supplement undergraduate course taught
by Peter Suber. Good collection of handouts.
http://www.earlham.edu/~peters/courses/log/loghome.htm
PHILOG:
The Danish Network for Philosophical Logic and its Applications.
http://www.philog.ruc.dk/
