In English, these translate respectively as ‘something one lives for’ and ‘a reason for being’. Although the meanings are similar, cultural attitudes toward the concept they embody differ.
Few possess a raison d’être. Those who live with an enduring passion for something can be consumed by it to the detriment of social relationships and a “normal” lifestyle. Thus, there are desirable and undesirable aspects to having a raison d’être.
Everyone, according to the Japanese, has an ikigai. Finding it requires a deep and often lengthy search of self. Such a search is regarded as being very important, since it is believed that discovery of one’s ikigai brings satisfaction and meaning to life.
Ikigai is used by the Okinawan meaning “reason to get up in the morning”: a reason to enjoy life.”
In a study on Okinawans, who have the highest life expectancy of any world population, Ikigai was noted as one of the 4 main contributing factors to their consistent long life expectancy.
(The other 3 include a nutrient dense low calorie diet, active lifestyle [gardening, walking, working, dancing. Not just going to the gym] and surrounding yourself with positive like minded friends and family.)