I'm trying to think back on my own diaries but I don't think I have ever written anything related to my PhD except indirectly for one on communicating science.

I don't think that possession of PhDs here is really all that in itself, but people's expertise in various areas developed through their careers or hobbies or through being a sodding polymath is what I feel I can't keep up with.

I do think most people would appreciate that where others aren't necessarily on par in terms of depth of expertise, it doesn't mean that they can't make a valuable layman's contribution to a discussion.  On occasion though some comments or debate back on a point comes in a bit too hard and that can be intimidating when you don't have detail of terminology or expertise to articulate your point very well.

Ad astra per aspera