Where did it come from? More than three years into the pandemic with untold millions of people dead, that question about the origin of Covid-19 remains widely disputed and fraught, with facts sparkling amid a tangle of analyses and hypotheticals like Christmas lights strung on a dark, thorny tree. One school of thought holds that the virus, known to science as SARS-CoV-2, spread to humans from a nonhuman animal, probably in the Huanan Seafood Wholesale Market, an emporium brimming with fish, meats and wildlife on sale as food in Wuhan, China.Another school argues that the virus was laboratory-engineered as a bioweapon to infect humans and cause them harm, and was possibly devised in a “shadow project” sponsored by the People’s Liberation Army of China. A third school, more moderate than the second but also implicating laboratory work, suggests that the virus got into its first human victim by accident at the Wuhan Institute of Virology, a research complex on the eastern side of the city, maybe after undergoing well-meaning but reckless genetic manipulation that made it more dangerous to people.If you feel confused by these possibilities, undecided, suspicious of overconfident assertions — or just tired of the whole subject of the pandemic and whatever little bug has caused it — be assured that you aren’t the only one.This story was recorded by Audm. To hear more audio stories from publications like The New York Times, download Audm for iPhone or Android.