Er, I am not defending the idea of one-way relationships between magisteria. The point was meant to highlight that magisteria is very much the wrong term.

As far as the one-way relationship, the term was not used to mean communication, causality, or anything else in particular.

The easiest example is a write-only folder on my computer. I can drop a file in that folder but do not have any direct measurement of its success or what happens to it after I drop it there. This relationship is "one-way" in the same way that my original statement was using "one-way." Likewise, a read-only file can be opened and viewed but not modified. This is also "one-way" in the same manner that I meant "one-way" in the original statement.

Both of these examples are not one-way in the manner that magisteria would describe one-way.

And again, I am not trying to defend this view. I am merely trying to describe why magisteria is the wrong term.

Prayer would be an example of dropping a file into a write-only folder. We do something and assume that something happens to it later. We don't have access to whatever happens because we don't have read access.

As a specific example of Eliezer's larger point, prayer is a natural attempt to influence the supernatural; so by that account, prayer must be futile.

This statement wouldn't make any sense in the cosmology of a typical theist. That cosmology may be completely wrong but using this statement to tell them that prayer is futile would make you sound like a complete nut. The discussion needs to start somewhere else.