Just one. The Mind.
It is the nature of the mind to analyse; to chop things up; to separate. Ego lives in the mind and gets malicious pleasure in being superior; condescending and so forth. The mind thinks in terms of 'me' and 'mine.'
The Spiritual Heart is infinitely different. It is like a child: spontaneous, pure, innocent, magnanimous and by nature likes to identify, to become one with. It thinks in terms of 'we' and 'ours.', and is filled with compassion, empathy and concern.
In the Spiritual Heart, Christians, atheists and agnostics do not exists, but the one indwelling Light in all. It has always been infinitely more important to me to love first, to serve first, then ask about religion later, if at all.
Why should I care if I'm a believer (whatever that word means), a non-believer or an atheist? I would rather feel Love in my Heart. Vanity of Vanity, all is Vanity, except to love God and serve Him in and through His Creation: mankind. How can I love what I cannot see, except in and through what I can see? You! much peace..