Exactly my point, perception is unreliable. It is easy for the eyes to misinterpret reality, or even for them to be actively deceived.

I said the same thing myself, having witnessed a number of miracles in my Pentecostal world. Once I lost my faith I was shocked to realize that nothing I'd witnessed was conclusive. Far from it, in fact. Having had a lot of 'backstage' access as the son of the pastor, more than one miracle turned out to have not been a miracle at all.