Part of the philosophizing in this poem is about the pursuit of the truth. It doesn't seem to be as important for Dickinson to pinpoint the truth in this poem as to search for it. This line makes us think that the pursuit of truth, however circuitous and sometimes confusing, is what will eventually lead to its discovery. It's deep, we know.
Too bright for our infirm Delight The Truth's superb surprise (3–4)
It seems like the weakness of humans is just as important to this philosophy as the truth is. We're not really able to handle the brilliance of the truth, and maybe it's a good thing that we can't figure it out all at once.
The Truth must dazzle gradually (7)
This line reiterates the ideas Dickinson touches on earlier in the poem. The truth isn't a pot of gold to be discovered someday after a long day of chasing rainbows. Instead it's something we're offered bit by bit, and that's the way it should be, because we're mere mortals and would be totally blown away if we discovered it all at once.