How do you typeset all those logical symbols so nicely?

LaTeX!

Here is a template that will get you started with logic in LaTeX.

How can I learn how to use LaTeX?

There’s a DeCal class this semester, LaTeX for Math and Science. There are also many online books and tutorials. Among the best:

• The Not So Short Introduction to LaTeX 2_ε (PDF)
• LaTeX wikibook

Where do I get LaTeX? Is it expensive?

It’s free. If you use Windows, you’ll want to get MikTeX (which contains the LaTeX system itself) and either WinShell or TeXnicCenter. If you use a Mac, you’ll want MacTeX. If you use linux, get TeXLive (on debian-based systems, apt-get install texlive).

How do I typeset logic using LaTeX?

I use this package for Fitch-style proofs. Here’s a template to get you started, and here’s the PDF it produces after processing with pdflatex.

Here’s the style file I use for the handouts: handout.sty. Put this in your working directory. Then your latex file can look like this:

\documentclass[11pt]{article}
\usepackage{handout}

\begin{document}

title{Your Title Here}
\author{Your Name}
\date{\today}

\maketitle

\section{Section one title}

Put your text here.

Math within a paragraph goes between dollar signs:
$\forall x(\neg(Gx \wedge Fx) \cond (Gx \vee \exists y Hyx))$.

If you want the math to be ``displayed'' (centered and set off),
use an equation or displaymath environment.  Here's an example of
a Fitch-style deduction in an equation environment:

\begin{equation}
  \begin{fitch}
    \fa \forall x (Gx \cond Hx)                 & \\
    \fj \forall x (Hx \cond Fx)                 & \\
    \fa\fh \framebox{a}                         & \\
    \fa\fa Ga \cond Ha                          & $\forall$ Elim 1 a/x \\
    \fa\fa Ha \cond Fa                          & $\forall$ Elim 2 a/x \\
    \fa\fa Ga \cond Fa                          & Taut Con 4, 5 \\
    \fa \forall x (Gx \cond Fx)                 & $\forall$ Intro 3-6 a/x \\ 
  \end{fitch}
\end{equation}

Some oddities to keep in mind:
\begin{itemize}
  \item Some punctuation characters need to be escaped, since they
    have special meanings in \LaTeX.  For example, \$50 and 30\%.
  \item For long dashes, use ---.  For dashes between numbers,
    use --.  For hyphens, use -.
  \item Left and right quotation marks are different in \LaTeX.
    Here's how you do ``double quotes,'' and here's how you do
    `single quotes.'
\end{itemize}

\end{document}

Peter Smith has a nice page, LaTeX for logicians, with some useful links. There’s also a LaTeX for linguists. You can use detexify to find the codes for symbols you want to use. If you don’t find what you want there, try the big list.

How do I get an upside-down iota (Russell’s definite description operator)?

In the preamble of your document,

\usepackage{graphicx}
\newcommand{\riota}{\mathrm{\rotatebox[origin=c]{180}{$\iotaup$}}}

Then just use $\riota$. (Thanks to Alexander McCormach.)

Alternatively, you can get the phonetic.sty package and put

\usepackage{phonetic}

in the preamble. (Thanks to Raul Saucedo.)