Here's one thing I'm worried about. What if discussion between those of widely varying ideological background assumptions is just intrinsically unproductive because they can never take basic concepts for granted? Even the best thinkers seem to mostly have strongly, stably different ideological outlooks. You could pre-select for ideology and possibly have multiple groups, but that has its own downsides.
You could pre-select for ideology and possibly have multiple groups
That would mean a collection of echo chambers which are worse than useless.
From Mike Darwn's Chronopause, an essay titled "Would You Like Another Plate of This?", discussing people's attitudes to life:
Conclusion, graphs, and references in article. As usual, I recommend reading Chronopause.com as Darwin has many good articles; to quickly link a few: