Monotheism, belief in one God, is the most important and foundational concept in Islam. This primary pillar of Islamic belief clearly states that there is nothing worthy of worship except God.

One of the most fundamental questions humans face is the question of meaning: what is the purpose of our existence, and how can we find purpose and meaning in this life?

God can only be grasped by relationship—by the ways in which we draw close to God and align ourselves with God. Ultimately, God can’t be grasped by this kind of belief.

In this sense, belief in God is similar to knowing you are in love. Just as you cannot prove you’re in love – it can only be experienced – so too belief in God is an experiential reality.

Similar declines in belief have been recorded regarding the devil, heaven, hell, and angels, with each one seeing double-digit declines in professed believers over the 22 years in question.