Being smart in a particular subject requires a certain coalescence of talent, training, and timing. Most people do not have the prerequisites to be smart in all

Being smart in a particular subject requires a certain coalescence of talent, training, and timing. Most people do not have the prerequisites to be smart in all subjects, or even a significant amount of them. The economic division of labor also encourages specialization rather than general expertise. This is why one should be wary of experts speaking far afield of their expertise.