By use of appeal to reason. A typical way of refuting an opposition to your argument is by showing the fallacies committed by the opposition. Logical fallacies are statements that are false by virtue of the principle of "non sequitur" or, literally, "it does not follow". For example, you may want to say that "just because X is true does not necessarily follow that Y is also true". A more concrete example is the statement "just because the ground is wet does not mean that it rained".