While one category of ignorance applies to what is not known, another category applies to the inability to assemble all the facts needed. For example, although there may be considerable understanding of the effects of single policies on single objectives, where multiple and sometimes conflicting effects and objectives of programmes and policies exist the processes for evaluating all these may be too complex, so that decisions are made in ignorance of all the relevant data.
Another type of ignorance allows for the knowledge to exist and also the capability and means to acquire it, but the will to do so is not present. Unwillingness to look at the facts constitutes intellectual bias. An emotional bias has the same effect, such as identification with a particular set of interests whether they are national, political, economic, ideological or religious. In the latter case, a tenet of Roman Catholic theology, for example, describes those who will never embrace Christianity due to their heredity, upbringing or environment, as 'invincibly ignorant', which aptly describes the 'closed' mind in any situation.
2. If all knowledge were within a man, and ignorance were wholly absent, that man would be consumed and cease to be. So ignorance is desirable, in as much as by that means he continues to exist (Jalaluddin Rumi).