If you can’t explain the best version of the other side, you don’t really understand your own.

Knowing what you believe is not the same as knowing why it beats the alternatives, and the only way to tell is to try stating those alternatives well. A weak version of the other side is easy to defeat and teaches nothing, because you built it yourself out of the parts you already found unconvincing. The test is whether they would recognize your description.

Write out the opposing case until someone who holds it would nod at the summary. Do this before the next argument rather than during. Whatever survives is a view you own instead of one you inherited.