Christian existentialists such as Søren Kierkegaard suggest that for one to truly have belief in God, one would also have to doubt one's beliefs about God; the doubt is the rational part of a person's thought involved in weighing evidence, without which the belief would have no real substance. Belief is not a decision based on evidence that, say, certain beliefs about God are true or a certain person is worthy of love. No such evidence could ever be enough to pragmatically justify the kind of total commitment involved in true theological belief or romantic love. Belief involves making that commitment anyway. Kierkegaard thought that to have belief is at the same time to have doubt.