Henry Hazlitt

The bad economist sees only what immediately strikes the eye; the good economist also looks beyond. The bad economist sees only the direct consequences of a proposed course; the good economist looks also at the longer and indirect consequences. The bad economist sees only what the effect of a given policy has been or will be on one group; the good economist inquires also what the effect of a policy will be on all groups.

– Henry Hazlitt, Economics in One Lesson [1946]