(Namespace: plural glossary)

A headmate's source is how they specifically came to be, as distinct from the origin of the entire system. Some headmates are sourced, and some are not.

Some headmates in a system may be sourced.

This means, rather than being invented wholesale or directly representing a version of the system's collective person, the headmate represents someone or something else, that already existed outside the system (or, in the case of some types of autojects, already existed as a different part of the system).

For example, a headmate might be sourced from a real person—often, but not always, someone the system knows—or from a work of fiction.

There is a subtle difference between source and sourced. Because of this, the terminology gets confusing around the antonyms listed above: core, host, original, and self might all be considered sources (well, host is usually considered more of a role, actually) and yet, a headmate whose source is one of these is usually not considered sourced. So, for example, you might say a self's source is that they are one of the system's selves, but you wouldn't say that that self is one of the system's sourced headmates.

Perhaps the most sensible way to look at it is this: If you were to ask a headmate, “what is your source,” then consider the following possible answers:

• “I'm the real one;”
• “I'm the one who was here to begin with;”
• “I'm just me;”

These are all valid and meaningfully distinct answers to the question, right? Even though they all amount to “you're asking the wrong question.”

Thus, asking a headmate “are you sourced” really means “if I were to ask you what your source is, would you give an answer that does not amount to telling me I'm asking the wrong question.”

That is to say, every headmate has a “source,” which is just however they specifically came to be (as distinct from the system's origin), regardless of whether they came from somewhere; whereas a “sourced” headmate is specifically one who came from somewhere.