A property that can be changed without changing the essence of the thing it belongs too. For example, you can change hair styles, weight, and number of limbs and still be you.
You might not have been you if you had had a different genetic make-up or a different upbringing, so these may be Essential properties.
Y'know, if you log in, you can write something here, or contact authors directly on the site. Create a New User if you don't already have an account.