Since we must discern the truth and goodness of complex and informationally-overwhelming issues (such as climate, health, race and war) how can this validly be done by ordinary people?

If we wrongly assume that correct judgment is reached from 'the evidence' then there would be no possible way that ordinary people can ever judge complex issues such as climate change, health (with respect to the birdemic and its peck), race justice, and the Fire Nation war (to mention just some of the Litmus Tests of 2023). 

But equally there is no way that 'experts' can evaluate these issues; since experts are all specialists, knowledgeable and competent (by current standards) only in ever-narrower fields; and there is no-such-thing (in the modern world, by current criteria) as a generalist-expert. 

What this means is that - IF correct judgment really-was reached from expert knowledge and skill applied to evidence; there can be no valid judgment on any complex issue; and the situation is inevitably one of the blind leading the blind. 

Of course, the actual situation is indeed overwhelmingly one of the blind (and purposively-evil) leading the blind (and passively-evil). But this situation is not inevitable. 

It would only be inevitable if correct judgment derived from expertise and evidence. But that is false. 

Correct judgment is derived from correct assumptions; and Good judgment is derived from motivation towards the Good (which is harmonious alignment with God's creation and its purposes). 

This means that valid discernment is possible to anyone who has the right attitudes. 

Roughly, 'right attitudes' means: 1. He takes the side of God/ Good/ Divine Creation and 2. He is able to discern whether or not 'information'/ theories/ attitudes/ opinions/ strategies/ policies/ laws etc come from those on the side of Good. 

Only if someone has Right Attitudes, can he evaluate 'the evidence' and learn from experience so that the inevitable mistakes get corrected. 

By contrast; those with wrong attitudes will interpret 'evidence' wrongly; and will neither acknowledge nor learn-from their wrongness.    

In other words; with 'right attitudes'; discernment is a matter of the provenance of assertions. 

"Provenance" means "where they come-from". 

All that need be known is whether the assertions come from the side of Good, or the side of evil. 

And it is very easy for those with Right Attitudes to know when assertions come from the side of evil: in fact - for those part of 'Western' civilization in particular - discernment of provenance has never been easier in the history of the world! 

In conclusion, not only is it easy for ordinary people validly to discern the truth and goodness of complex issues - in practice ordinary people who are spiritually outside of The System are just about the only ones who can make valid discernments. 

Insofar as expertise and 'evidence' have anything to do with it, they are a disadvantage to discernment; and there is an (obvious!) overall-inverse relationship between expertise and being-informed about a complex issue - and the chance of reaching true and Good conclusion on that issue. 

Note: This is an extension into the spiritual realm of the psychological phenomenon of clever sillies that I floated some years ago; and which has gained considerable traction in some quarters. That is, I sought explanations for the observation that (up to a point) the more intelligent a person, the less likely they are to be correct about matters of common sense and personal experience. Here, intelligence is only a part of wrong discernment insofar as it is a proxy for being an informed and trained 'expert' - but for several decades there are deliberate but indirect strategic policies that reduce average intelligence among the class of experts. Furthermore, the clever sillies idea fails to take into account that motivation is of prime importance to discernment and therefore Good outcomes. Good is more than a choice of lesser evils, and requires a transcendental, next-worldly, orientation.