The notion - a fallacious notion - that done will emerge, is common in some circles of Agile and especially those agile advocates proferring No Estimates.
The Greeks and Romans had a good understanding of most things we take for granted today. Here's an example.
If we don't know what Done looks like in units of measures meaningful to the decision-makers, we'll only get to Done, when we run out of time and money.
Since all project work operates in the presence of uncertainty, getting to done means making estimates. These uncertainties create risk - reducible (epistemic) and irreducible (aleatory) and the handling strategies for the risks create by these uncertainties.
