Your logic is devastating. I guess you win.
Sure, that would count as evidence. Can you show me such a deadlifter? And, what's far more important, can you establish that his fallen arches were caused by deadlifting without arch support?
Here's the logic of our two position:
1. Lots of people (including me) deadlift with flat, crappy shoes or no shoes at all, and they don't develop fallen arches. That is sufficient evidence to conclude deadlifting without foot support is not, by itself, a cause of fallen arches.
2. Some people who deadlift that way do develop fallen arches. But that is not sufficient evidence to conclude that deadlifting without foot support caused that condition. The root cause could be a structural abnormality of the foot that was aggravated by deadlifting.
Long story short: Your position bears a heavier burden of proof than mine. Dress accordingly.
That sounds plausible. I'm not saying that feet don't get trained if they are encased in special shoes (though I doubt that they get trained in the same way and to the same extent as with unsupported lifting). What I'm challenging is the suggestion that healthy feet require such shoes for deadlifting, that without such shoes, one cannot develop the stability and balance needed in a heavy pull. That suggestion is clearly false, as evinced by people who pull very heavy DLs without shoes and don't develop any foot problems. (I'm not sure that wearing a belt is analogous to wearing special support shoes, but no need to go into the tall wheat on that one.)
Your logic is devastating. I guess you win.
It guts me. Tell all your friends.
I swear I'll do better next time. Really. I promise.
Man, what do you want from me? You've humiliated me in front of millions of people, embarrassed me in front of my friends and family, destroyed my professional credibility, so what's left? You want my blood???