What does this thought experiment show us? Primarily it reveals that we do not get our identity simply from within. Rather, we receive some interpretive moral grid, lay it down over our various feelings and impulses, and sift them through it. This grid helps us decide which feelings are “me” and should be expressed - and which are not and should not be. So this grid of interpretive beliefs - not an innate, unadulterated expression of our feelings - is what gives us our identity. Despite protests to the contrary, we instinctively know our inner depths are insufficient to guide us. We need some standard or rule from outside of us to help us sort out the warring impulses of our interior life.

And where do our Anglo-Saxon warrior and our modern Manhattan man get their grids? From their cultures, their communities, their heroic stories. They are actually not simply “choosing to be themselves” - they are filtering their feelings, jettisoning some and embracing others. They are choosing to be the selves their cultures tell them they may be.

- Tim Keller, Preaching: Communicating Faith in an Age of Scepticism, 135-136.