Some interesting parallels can be made between mentats and oracles; both groups look for possibilities and seek to balance them.
There's only one major difference: the degree of abstraction.
Mentats withdraw from the world (and from themselves), so they can see from a clear distance. They create a mental space where they compose abstract pieces based on their outside experiences.
If the pieces fit, superb.
If they don't, continue until they do.
The tool and method by which the pieces should fit is supreme logic.
The difference between a good mentat and a bad mentat is that the good mentat is aware of the fallacies of incorrect use of logic - namely, a good mentat knows that logic is not more than nothing.
Decision making is entirely outside the mentat process.
Oracles don't withdraw from the world and don't observe from a distance.
Oracles turn themselves inside-out to create a balancing tool of themselves.
Their tool isn't logic; their tool is awareness itself.
By creating at zero-distance instead of at total-distance, power is immense; complete.
Oracles don't have the benefit of self-security, only of balance. Fear, unaligned presence, causes distortion of perception.
Self-discipline becomes a whole new concept.
It would have been interesting to see what kind of universe would have been created if oracles developed the discipline necessary to manage such power (the kind mentats had with their own power).
The Spacing Guild wasted a lot of time.