Boundaries define us. They define what is me and what is not me. A boundary shows me where I end and someone else begins, leading me to a sense of ownership.
Psychology must be a practical science, concerned with the how and why of mental operations.
In the quest to understand quantum gravity, we are like children playing on the shore of a vast ocean, occasionally finding a smooth pebble or a pretty shell, while the great ocean of truth lies undiscovered before us.
The only source of knowledge is experience.
Be fearless in the pursuit of what sets your soul on fire.