The more I am able to affirm others, to say “yes” to them in myself, by discovering them in myself and myself in them, the more real I am. I am fully real if my own heart says yes to everyone.
I will be a better Catholic, not if I can refute every shade of Protestantism, but if I can affirm the truth in it and still go further.
So, too, with the Muslims, the Hindus, the Buddhists, etc. This does not mean syncretism, indifferentism, the vapid and careless friendliness that accepts everything by thinking of nothing. There is much that one cannot “affirm” and “accept,” but first one must say “yes” where
one really can.
If I affirm myself as a Catholic merely by denying all this is Muslim, Jewish, Protestant, Hindu, Buddhist, etc., in the end I will find that there is not much left for me to affirm as a Catholic: and certainly no breath of the Spirit with which to affirm it.
Thomas Merton in Conjectures of a Guilty Bystander quoted in Thomas Merton: Essential Writings Christine M. Bochen