ABSTRACT
This chapter examines the polarized debate over population-wide masking during Covid-19, contrasting the simplicity of public messaging with the complexity of the evidence. It reviews the known pros and cons of masks, distinctions between wearer protection and source control, and the state of evidence before the pandemic. The authors explain why studying masks at the population scale is methodologically difficult, and show how different study designs produced divergent results. They identify instances of “mask dogma” on both sides of the debate, along with flawed causal inferences, unrealistic expectations of high-quality evidence, and selective interpretation of disappointing results. The chapter also explores how precautionary reasoning morphed into claims that any cost was justified, sometimes ignoring potential biases or uncertainties. The analysis illustrates how dogma – in this case, both pro- and anti-mask – can distort scientific discourse, create unnecessary social tension, and impede proportionate, context-aware public health policy.
