Herbalist: Many of my customers find that their physical coordination improves after drinking juice containing certain herbs.
Conclusion (So)
There is no reason not to try my herb juice.
Evidence
Customers report improved physical coordination.
A few doctors say the herbs are potentially harmful, but doctors are always trying to maintain a monopoly over medical therapies.
Evaluate
If we're the other lawyer and we're arguing, there IS some reason not to try this herb juice what would we say?
We could start with,
And the author will say,
We need a response. We could say,
If we know our Famous Flaws, then we'll hopefully recognize this as a classic Ad Hominem. That's when the author dismisses someone's view because they (1) have an ulterior motive / vested interest, or (2) have conflicting past behavior / hypocrisy.
In this case, the author is trying to immediately disqualify what these doctors are saying just because doctors do have a financial interest in herbal treatments being bad ideas.
Goal
Look for an answer addressing the Ad Hominem move where the author fails to seriously address the concerns of the doctors and wipes them away by pointing out their self-interest.
Or, there might be an answer saying, (e.g. its awful taste, the farts it gives you, etc.)