Johnson argued that the most truthful life-writing is when 'the writer tells his own story', since only he knows the whole truth about himself. (He does not use the word 'autobiography', which only came into circulation in the early 19th century.) Those who write about another may want to over-praise him or 'aggravate his infamy'; those who write about themselves, he says - optimistically - have no 'motive to falsehood' except 'self-love', and we are all on the watch for that.