Psychology and learning

Twenty-sixth on this list is a dedução, and the English difficulty is not in the noun but in the verb underneath it. Portuguese has one verb, deduzir, and it does both jobs without blinking: deduzir uma conclusão das premissas, and also deduzir as despesas do rendimento. English split that verb in two and keeps the halves strictly apart. « To deduce » is the reasoning one — a detective deduces, a reader deduces from the evidence — and it never touches money. « To deduct » is the arithmetic one: tax is deducted at source, a sum is deducted from an invoice, and nothing is being worked out. Writing that an inspector deducted the motive, or that an employer deduces the pension contribution, produces a sentence that sounds educated and lands wrong. The seam shows in the noun, which was never divided. « Deduction » serves both verbs, so a deduction of forty euros and a deduction from the premises are one word doing the two jobs Portuguese does all the way through. Both go back to deducere, to lead down from something, and both keep that picture: something is taken from what came before.