Every inch of this universe is different. Even if you simply look around the room you are in right now, every bit of it is different. Sri Adi Sankaracharya says in the Bhaja Govindam, it is because of the different types of containers or upadhis there are so many differences among human beings. This container is not very gross like the physical holders we may see. It is very subtle. It is in the form of qualities that we express.
These qualities too are only of three types—Sattva or brilliant, calm, cheerful and all the possible good qualities that we may love to possess; Rajas or active, dynamic, restless, wanting to do this and that, having high ambitions and goals to achieve; Tamas, the quality of being slow, dull, sleepy, inert, postponing and always sloppy in one’s ways.
Even though the main qualities are only three, this chemistry allows for a million permutation and combination spread throughout the day, and throughout one’s lifetime that it creates many differences among human beings. Each one is a unique combination of these three qualities at many levels and that causes all the differences we perceive.
The master here is just training our mind to see the unity behind all this diversity. Though everything appears very different in terms of the different races, colours and nations among the human species, the myriad qualities that people express—anger, hatred, jealousy, love, kindness, gratitude, arrogance, compassion, brilliance, and also the different states of life we all are in—the life that plays through all these is just one.
The petrol is the same, but it powers a moped, a scooter, a geared bike, a small car, a luxury vehicle, an auto or a public transport bus. On the face of it so much thought is given to the type of vehicle in which we travel and keep improving our status in life by going in for the higher end vehicles, but the power that drives them all is the same petrol. In the same way, human beings may be great, may be brilliant achievers or may just be living a run-of-the-mill life, but the energy that drives them all is one and the very same life force which we call consciousness.
Sri Adi Sankaracharya says that while the life is the same, these differences in nomenclature and feelings are superimposed on ourselves and others just as different colours applied to different test tubes of the same water may make them all look different. Humans are like those test tubes which contain the same water. The many differences we see in ourselves are different qualities and aspirations that we inject ourselves with.