Experts are people who know a lot about something. Alternatively, experts are people believed to know a lot about something that other people generally know very little about.
Having an expert on your side during a discussion is a big help and can very easily be the trump that tips the scales in your favor.
Here follows a true story:
I once had an article about Norway rejected because someone knew "a Scandinavia expert and(!) professor". Doh!
Therefore, an essential part of the prepapration for any discussion should be the gathering of useful experts in a variety of different fields.
Rememeber: If in doubt, a llama expert always trumps a Peruvian goat herder.