"We shall have to say he is a learned ignoramus, which is a very serious matter, as implies that he is a person who is ignorant, not in the fashion of the ignorant man, but with all the petulance of one who is learned in his own special line.
"And such in fact is the behaviour of the specialist. In politics, in art, in social usages, in the other sciences, he will adopt the attitude of primitive, ignorant man; but he will adopt them forcefully and with self-sufficiency, and will not admit of--this is the paradox--specialists in those matters. By specializing him, civilisation has made him hermetic and self-satisfied within his limitations; but this very inner feeling of dominance and worth will induce him to wish to predominate outside his specialty." -- The Revolt of the Masses, p. 112
Ortega y Gasset could not have better described the attitude of many contemporary physicists, such as Hawking, towards philosophy. While I would never dream of challenging anything Hawking says about, for instance, about black holes, he feels perfectly confident expounding on philosophy, without any apparent familiarity with the subject.