Overview#A universal identity system must channel and enable the inter-working of multiple identity technologies run by multiple identity providers.
One reason there will never be a single, centralized monolithic system (the opposite of a metasystem) is because the characteristics that would make any system ideal in one context will disqualify it in another.
It makes sense to employ a government issued digital identity when interacting with government services (a single overall identity neither implies nor prevents correlation of identifiers between individual government departments).
But in many cultures, employers and employees would not feel comfortable using government identifiers to log in at work. A government identifier might be used to convey taxation information; it might even be required when a person is first offered employment. But the context of employment is sufficiently autonomous that it warrants its own identity, free from daily observation via a government-run technology. Customers and individuals browsing the Web meanwhile will in many cases want higher levels of privacy than is likely to be provided by any employer.
So when it comes to digital identity, it is not only a matter of having identity providers run by different parties (including individuals themselves), but of having identity systems that offer different (and potentially contradictory) features.
This demonstrates, from yet another angle, that different identity systems must exist in a metasystem. It implies we need a simple encapsulating protocol (a way of agreeing on and transporting things). We also need a way to surface information through a unified user experience that allows individuals and organizations to select appropriate identity providers and features as they go about their daily activities.
The universal identity metasystem must not be another monolith. It must be polycentric (federation implies this) and also polymorphic (existing in different forms). This will allow the identity ecology to emerge, evolve, and self-organize.