[vishalchandra]

Step 1. Make sure that I am disagreeing in the right spirit and communicating in the right way. See disagreement diagram: http://commons.wikimedia.org/wiki/File:Graham%27s_Hierarchy_... Typically this should ensure that the following discussion is done in the right spirit because I would guess developers tend to be logic driven.

Step 2. In the scenario that even this does not work or cannot be applied easily, then ask that "If we wanted to test out which option between these two, three approaches will work better, than what test could we conduct ?" Focus on defining a test to validate assumptions, rather than arguing for or against an option.