Human commonality, or human nature
Plato's theory of ideas believes that when we talk about a thing, the reason why we can define it is that it is different from other things because each type of thing has the same thing as across the vast time and across the barriers of thousands of miles. The commonality of human beings, or human nature, lies not in their intelligence, but in what Russell called "prudence", that is, calculating the consequences. The reason why people care about consequences is that people always consciously pursue long-term and even eternal meaning, always limit the animal nature of life and death, and set aside benefits to give dignity to all around them. The consciousness that these benefits cannot be measured is human nature.