12. Newton’s concentration was such that he often forgot to eat and sleep
Newton demonstrated powers of concentration which served to make him in many ways the prototype of the “absent-minded professor” of later ages. He often breakfasted on the cold dishes which had been set out for him as his supper the night before, having been so deep in thought throughout the night that he forgot to either eat or sleep. Late in life, he told his half-niece that during his days at Cambridge his cat had become fat through eating the meals which sat on his side table as he worked on some problem or another, unnoticed by him. On being reminded of his meal sitting unattended, he would often take one or two bites of the repast while standing, before being drawn away again by whatever was occupying his attention, according to his secretary at Cambridge.
John Locke, who like Newton was a Fellow of the Royal Society, once wrote that though he considered Newton a friend, he was concerned that he was difficult at times to deal with, “and a little too apt to raise in himself suspicions where there is no ground”. This and similar observations by contemporaries and later biographers led to Newton being described as withdrawn and forgetful due to a disturbed mind, afraid to engage in social activity because of a suspicious and paranoid personality. His fears of criticism led to his delays in publishing much of his work until they were overridden by the fear that another would receive the credit for his discoveries. At his death, much of his work remained unpublished.