You don't understand all of reality only through objective observation and objective testing.
I do.
I don't
experience all of reality through objective observation and objective testing. In fact, I don't experience
anything that way. I experience everything by experiencing it, subjectively.
But objective testing and objective observation (which includes observation of others' accounts of what they have observed and tested) is the only way to
understand any of the things I'm experiencing. "Pure experiencing" can have value but by itself it
does not lead to understanding.
Experiencing thunder results in something like, "Loud noise! Danger! Run away!" which might have some survival value under primitive conditions.
With a small amount of understanding, we learn, "Thunder means danger of lightning. Hide away in places less exposed to lightning." That's more valuable knowledge, but you can only get there via objective testing of questions such as "Is the occurrence of lightning correlated to the occurrence of thunder?" and "Does thunder ever cause harm in the absence of nearby lightning?"
More advanced objective testing and observation leads to the deeper understanding that thunder is the sound generated by lightning, lightning is atmospheric electrical discharges, and structures can be protected from lightning using pointy metal rods.
There are experiences we don't yet understand, such as the experience of the divine. "Divine presence! Awesome! Worship!" But in that case, all attempts at objective observation and testing (e.g. the entirety of theology) have failed to produce any consistent understanding (hence, a million different religions), probably because we've been observing and testing the wrong things (e.g. the nature and wishes of the entity-that-is-present in the divine-presence experience, which will not be productive if there is no such entity). At that point, we can either denigrate understanding and be satisfied with the non-understanding of the pure experience (putting a good face on cowering from thunder), or engage yet deeper and more advanced objective testing and observation (such as brain scans).