This form would be used in a sentence where the speaker is considering a scenario in which they would present evidence or arguments to disprove a claim or statement. For example, "Si nous avions les preuves nécessaires, nous réfuterions l'accusation" which translates to "If we had the necessary evidence, we would refute the accusation." It implies a potential action dependent on certain conditions being met. The conditional tense lends a degree of politeness or softens the directness of a statement, suggesting a hypothetical or less assertive stance than a direct present or future tense.