The principle that says to always try to understand the strongest, most persuasive version of an argument is called the principle of

principle of authority

Explanation:

In simple words, That is the principle that individuals join the ranks of reliable, certified professionals. Physiotherapists, for instance , are likely to convince more of the clients to stick with the prescribed fitness regimes by showing their medical certificates on the doors of their treatment rooms.

This. helps them to make their point more reliable and strong with less effort. Thus, from the above we can conclude that the given case relates to principle of authority.