Philosophy of science

The twelfth entry is variável de confundimento, and the noun inside it is built straight off confundir, a verb Portuguese uses for everything from a muddled reader to a lurking third cause. English cannot do that, because the Latin verb behind it arrived here twice and set up two households. Confundere meant to pour together, con- with fundere, to pour, the root that also gives « to fuse » and « foundry ». One line came through Old French and gave « to confound ». The other came from the past participle confusus, which entered English as an adjective and only later grew a verb of its own, « to confuse ». For centuries the two overlapped. Then the sciences took one of them and left the other alone: a « confounder » or a « confounding variable » is a named technical object, the third quantity that moves the other two, while « confusing » stayed with the reader who has lost the thread. So a idade era aqui uma variável de confundimento is not about anybody being confused. Nobody in that sentence is muddled; a third cause is simply doing work that had been credited elsewhere.