问答题 If there is one person to blame for economists'habit of commenting on everyhing,it is Gary Becker,who died on May 3rd.Not content with studying the world's economies,he was the first prominent economist to apply economic tools to all aspects of life.He revealed that people are often purposeful and rational in their decisions,whether they are changing jobs,taking drugs or divorcing their spouses.This insight,and the work that followed from it,eamed him a Nobel prize in 1992.No less an eminence than Milton Friedman declared in 2001 that Mr Becker was"the grealest social scientist who has lived and worked in the last half-century".At the heart of Mr Becker's work was the view that"individuals maximise welfare as they conceive it."Welfare need not mean income;it could derive from the pleasure of selflessness.