When people of differing faith traditions get together they like to argue about whose version of doctrine is correct. How often do you see anyone change their mind as the result of such a discussion? Perhaps a better approach is to compare practical, visible measures of the beneficial effects of adopting a particular faith. Are the people who convert to this faith more loving and kind, more generous and less violent than they were before? This is a stronger argument for the validity of a faith than one based on doctrinal correctness. Transformed lives are irrefutable evidence.
Related Resources:How to Hear God's Voice!