A Colony (n.) can lose its members one by one without being harmed; an individual is whatever cannot be lost like that.
The Colony (n.) is the adult and the free individual its larva: the individual is younger than the colony it will found.
A Colony (n.) is not a super-organism whose members are mere organs; its members are incomplete individuals, more incomplete the less they can be detached.
The Colony (n.) never ages because it never runs ahead of or falls behind its own present; life invented the separate, mortal individual to get that step out of phase.
The Colony (n.) is where life stays put; the free individual is its messenger, a detachable bud that carries the colony's information across space to begin another.