Externality is an illusion, you are everything...
It's quite simple, you are the universe becoming aware of itself.
We walk around every day holding onto the idea that we are separate from each other, that we are insignificant beings who exist for 80 or 90 years, if we're lucky, and then vanish into nothingness. This could not be further from the truth!
You ARE the universe! You are learning what love is, you are learning how connected you are to everyone and everything. When you separate yourself from the rest of life around you, you are subverting the true nature of your existence. You ARE life, you share life with everything else that is living.
Yes, we all experience our worlds from our unique perspectives of awareness, but we are all life, learning about ourselves and our existence. Just because one person's experience of life is different from another person's does not mean that the core of life itself is not shared at the deepest levels.
You ARE the universe just as I am, and everyone else. The sooner we embrace this truth, the sooner we live in selfless compassion and the sooner life truly flourishes for all.
Just remember, even for one day, as you go about your activities, YOU are all of life and the universe is contained within you throughout this journey of existing. Welcome home.