Modal verbs and degrees of certainty
English · Key Stage 3 · The School
A scale, not a single meaning
MODAL VERBS express how certain, possible or necessary something is. From least to most certain: might, could, may — possible. Should, ought to — likely, or advised. Will, must — near-certain or required. "It could happen" and "it will happen" sit at opposite ends of the same scale, describing very different levels of confidence.
Hedging in argument writing
A careful writer HEDGES a claim that is not fully proven: "This may suggest that..." rather than "This proves that...". Hedging is not weakness — it is honesty about the strength of the evidence, and examiners reward writing that claims exactly as much as the evidence supports, no more and no less.
Modal verbs change how forceful an argument sounds
"We must act now" reads as urgent and certain. "We could consider acting" reads as tentative, almost reluctant. A persuasive writer chooses the stronger modal verbs deliberately — "must", "will", "cannot afford to" — to make their argument sound more urgent and less open to doubt.
A scientist has some early data suggesting a new drug reduces symptoms. Overclaiming: "This drug cures the condition" — far stronger than the evidence supports, and dishonest. Accurate hedging: "This drug may reduce symptoms, though further trials are needed" — matches what the early evidence actually shows. Underclaiming: "This drug might possibly have some effect, perhaps" — so hedged it barely says anything useful at all. The middle version is the only one that is both honest and useful, and modal verb choice is exactly what separates the three.