5 Words for Strengthening Arguments

To provide concrete evidence or proof that supports or confirms a claim or statement

Substantiate means to give substance to a claim — to back it up with something solid. An assertion without evidence is hollow; when that evidence is supplied, the claim is substantiated. The word carries a slightly formal, procedural flavour: you substantiate allegations in court, substantiate findings in a research paper, substantiate accusations in journalism. It implies that the claim existed first and the evidence has been marshalled to support it. In RC passages, when a writer says a claim needs to be substantiated — or that it has been — they’re flagging the quality of the evidential relationship between a statement and its support.

Where you’ll encounter it: Legal writing, scientific reporting, journalism, academic arguments, any RC passage discussing the burden of proof or the quality of evidence

“The prosecution’s case rested on circumstantial evidence, and the defence argued that the allegations had never been properly substantiated by any direct forensic link between the defendant and the crime scene.”

Powerfully persuasive through clear reasoning and well-organised logic; compelling and convincing

Cogent comes from the Latin cogere (to compel, to drive together), and that origin is revealing: a cogent argument doesn’t just present reasons — it drives them together into a conclusion that the reader is compelled to accept. The word describes the form of persuasion as much as its content. An argument can be substantiated (well-evidenced) without being cogent (poorly organised, unclear in its logic), and it can appear cogent while resting on flimsy evidence. In RC passages, cogent specifically signals that the argument’s logical structure is sound and its reasoning is clear and compelling — a higher compliment than “interesting” or even “well-evidenced.”

Where you’ll encounter it: Academic writing, legal briefs, philosophical arguments, editorial writing, any RC passage evaluating the quality of an argument’s logical structure

“The barrister’s closing argument was widely praised for its cogent presentation of a complex chain of events, reducing six weeks of testimony to a clear, logical narrative that the jury could follow without difficulty.”

Capable of being defended, maintained, or upheld against objection; a position that can withstand scrutiny

Tenable comes from the Latin tenere (to hold), and the image is apt: a tenable position is one you can hold when challenged — it doesn’t collapse under pressure. The word is often used in its negative form (untenable) to signal that a position has been fatally undermined. Crucially, tenable doesn’t mean correct — a position can be tenable (defensible, reasonable) without being true, and it can be true without being well-enough argued to be tenable. In RC passages, when an author says a position is tenable, they’re granting it the status of serious consideration, even if they don’t ultimately endorse it.

Where you’ll encounter it: Philosophical debate, policy analysis, academic argument, legal reasoning, any RC passage evaluating whether a position is viable or defensible

“While the committee acknowledged that the original interpretation of the clause remained tenable, it concluded that the amended reading was more consistent with the legislation’s stated intent and purpose.”

Impossible to dispute or deny; so clearly established that no reasonable argument against it exists

Incontrovertible is the superlative of the argument-strength spectrum. Where substantiated means “supported by evidence” and cogent means “logically compelling,” incontrovertible means “beyond dispute” — the evidence or reasoning is so complete and so definitive that there is simply no credible counter-position. It’s a strong claim, and careful writers use it sparingly. In RC passages, when an author describes evidence as incontrovertible, they’re making a statement about the finality of the case — this is not a matter for further debate. Exam questions sometimes ask whether the author’s confidence in calling something incontrovertible is justified by the evidence presented, which requires close reading.

Where you’ll encounter it: Legal writing, scientific consensus discussions, historical accounts of decisive evidence, editorials making bold claims about established facts

“The DNA evidence was incontrovertible: three independent laboratories using different techniques had reached identical conclusions, and the defence’s own expert ultimately conceded that no alternative explanation of the data was scientifically credible.”

To confirm or strengthen a claim by providing independent supporting evidence that aligns with it

Corroborate is the most procedurally specific word in this set. It doesn’t just mean “support” — it means support from an independent source. In a court case, a witness corroborates testimony when they confirm it without having coordinated with the original witness. In science, a study corroborates a finding when it replicates the result using a different methodology. This independence is what gives corroboration its particular strength: it’s not just more of the same evidence, it’s convergent evidence. When RC passages describe evidence as corroborating a position, the key implication is that multiple separate sources are pointing in the same direction — and that convergence is persuasive precisely because it wasn’t engineered.

Where you’ll encounter it: Legal proceedings, scientific methodology, investigative journalism, historical research, any RC passage discussing the role of multiple sources in building a credible case

“The historian’s controversial thesis, initially met with scepticism, was gradually corroborated by a series of newly declassified documents from three separate national archives that had not been available to earlier researchers.”