Fourth Order Ignorance (4OI)—Meta Ignorance:
I do not know about the Five Orders of Ignorance.
As mentioned, I added this initially as a nod to recursion: not knowing about the Five Orders of Ignorance naturally includes not knowing about 4OI. So 4OI includes 4OI.
At a more practical level, there are several artifacts of 4OI:
In software development:
The assumption that the system is the product that we deliver to the customer. It is not. The product is the knowledge contained in the system. The developed system is the byproduct of the learning activity that acquires the necessary knowledge.
The belief that software development is the process of crafting our knowledge into an executable form. It is mostly not. Most of the effort in development is the discovery of the necessary knowledge. Once that has been done, transcribing it into the executable form is usually pretty simple.
Therefore software development is a learning activity. However, most companies do not view it that way and tend to manage as a product production activity. This is a mistake caused by 4OI.
The only part of software process that truly conforms to the Five Orders of Ignorance is testing. This is the only part of the software development lifecycle that intentionally confronts 2OI and uses processes that expose ignorance.
In general:
While society applauds and rewards the possession of knowledge, acknowledged ignorance is also valuable.
Assessment of our levels of knowledge (and ignorance) are necessarily limited. This assessment always require access to other sources of knowledge that are also limited.
Ignorance is present at both the artifact and the process levels: there are things we may not know and there are things we may not be able to find out (including what it is we don't know).
The recursive behavior of knowledge is confusing and may be uncomfortable to consider, but that is mostly an artifact of our linear reasoning process. We would like our logic to be straightforward and transitive (If a->b and b->c, then a->c). But consideration of knowledge is mostly not like that because we are forced to define it in terms of itself.
There are many more epistemological, phenomenological, and philosophical considerations when we consider this thing called "knowledge" but it is time to turn our attention more to ignorance.