Typesetting Unicode characters with XeTeX and fontspec

Question

Upon advice I started to use XeTeX to typeset Unicode characters. It did not work.

Then I started to use fontspec. No output was generated for ∃.

What else should I do to make it work?

Answer 1

∃ is a math symbol (U+2203), so use a math font and math environment. You can e.g. use unicode-math:

\documentclass{article}
\usepackage{unicode-math}
\begin{document}
$ ∃ $
\end{document}