When we experience things we don't know/haven't known/didn't know, we may be able to broaden our minds.
I have been following the thread with interest, unable to decide which I find the most natural. I have finally realised that I find none of them natural. It's not the tense, but the combination of not-knowing and then experiencing 'things'; it just doesn't work for me.
I think we can experience things we haven't met/encountered/experienced, etc before, and we can possibly experience the unknown (though there is only one citation in COCA, while there are thousands of other words that are experienced). However, I don't think we can know (or not know) things we can experience.
This is just a personal feeling.
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