The obligation is to respect the human dignity of each and every human person and to respect each human person’s freedom of conscience. There is no need to respect beliefs that violate logic or human decency. For example, someone who believes that the earth is flat deserves to be treated with kindness and personal dignity but he does not deserve to have his belief in a flat earth respected or affirmed. In like manner, someone who believes in the occult and/or in worshipping Satan continues to have inalienable human dignity but should not expect Christians to respect or affirm beliefs that directly contradict the Christian gospel.
One must be careful though not to dismiss others’ beliefs lightly and without due consideration. Just because someone is a non-Christian does not mean he or she may not have valuable insights derived from religious beliefs that contain some truth. The challenge is to know what you believe well enough to be able to pan incomplete information from other religions and to find the nuggets of wisdom buried within. The Second Vatican Council, in the document Nostra Aetate, taught:
… [O]ther religions found everywhere try to counter the restlessness of the human heart, each in its own manner, by proposing “ways,” comprising teachings, rules of life, and sacred rites. The Catholic Church rejects nothing that is true and holy in these religions. She regards with sincere reverence those ways of conduct and of life, those precepts and teachings which, though differing in many aspects from the ones she holds and sets forth, nonetheless often reflect a ray of that Truth which enlightens all men. Indeed, she proclaims, and ever must proclaim Christ “the way, the truth, and the life” (John 14:6), in whom men may find the fullness of religious life, in whom God has reconciled all things to himself.
The Church, therefore, exhorts her sons, that through dialogue and collaboration with the followers of other religions, carried out with prudence and love and in witness to the Christian faith and life, they recognize, preserve, and promote the good things, spiritual and moral, as well as the socio-cultural values found among these men (NA 2).
What is Truth? by Michelle Arnold