The concept of unity in diversity is used to express harmony and unity between individuals or groups that are different from each other. The concept of unity without uniformity and diversity without fragmentation is based on the understanding that difference enriches human interaction. This is in contrast to unity based solely on tolerance of physical, cultural, linguistic, social, political, religious, ideological, and/or psychological differences. Throughout Western and Eastern Old World cultures, this idea and related phrase date back to ancient times.