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My PhD supervisor died in June. I’d met with him only days earlier so that he could painstakingly revise my manuscript, giving me several hours of his precious time. He had a way of asking the very questions I didn’t want to answer, highlighting the limitations of my work that I’d been trying to hide or skim over. “You need evidence,” he’d claim, jabbing a forefinger at one of my many ‘unsubstantiated assertions’. He hated those. But he loved a good reference — although not too many for each assertion, mind you.