The author contradicts themself.

> Stop thinking that finding a flaw is a contribution. It's half of a contribution at best. The other half is "and here's how we might solve that." If you're pointing out a problem without offering a path through it, that's not contributing.

So... finding a flaw is "half" of a contribution, but it also isn't a contribution?

Critical thinking is valuable. Yes, it can sometimes be counterproductive, but it can also be steered in a productive direction.

If someone criticizes something, ask them to elaborate. Why couldn't this work? What are the exact roadblocks? Is it based on prior experience, or gut feeling? If it's based on experience, how similar is the current situation to their past experience?

Chances are that after some prodding their criticism turns out to be a non-issue, or far less of an issue than they originally thought. In either case, the discussion itself often steers the group towards a better solution, so bringing up potential concerns, even if they're invalid, is often a good exercise.

The skill is aiming for the right moment to bring it up, having a bit of tact in the delivery, and not burying your head in the sand and being defensive (or offensive). Too often people attach their ideas to their identities, which is the root cause of why design discussions can be frustrating and nonproductive.