KL asked what is an Expert. This is what I scribbled on the way home from the airport. (This was a brain dump, so apologies for the masculine articles; they are the result only of introspection.)
Starts with a knowledge of facts, insofar as they are known, and their interpretations. Combines this with constant observation and questioning of these sources.
Aims to have a deep knowledge in his field, and a wide understanding in relates ones. Knows where the gaps in his knowledge lie, and how to fill those in when they intervene with the ability to understand and explain. Recognises his limits, and tries to be conscious of his bias, such as it is.
Combines a long view to detect trends, and an appreciation of the potential impact of individual actions.
Has a refined bullshit detector.
Uses all of the above to explain patterns of development, the context of decisions made, and the perspective of the people and organisations making these decisions.
When communicating, tries to empathise with his audience’s perspective, and adjusts to their level of interest, but addresses them as equals.
Explains how his field matters, to whom, and why. Is able to engage peripheral audiences by revealing the connections between his field and their sphere of action or area of interest, if this is possible.
Combines confidence in his views with the humility to admit openly their limits. Has the patience to break down his explanations so that people will appreciate where this confidence stems from, and the openness to admit error or lack of insight.