I have a lot of pages, all of which require the file characters.php. This file contains constants which define many things in my website. They are
require
characters.php
A constant must not have any $ sign at the beginning. Try const HUMAN_HEALTH = 1.1 instead.
$
const HUMAN_HEALTH = 1.1
As Marc B mentioned, const outside classes is only available up from PHP 5.3.
const