The social theory of Critique is a far cry from Being and Nothingness , which had asserted that social groups were mere psychological projections ( Being and Nothingness, ). Critique introduces a new technical concept, that of “mediating third parties,” to explain the nature of groups above and beyond I-thou relations (pp. 100-9). Mediating third parties are members of groups who temporarily act as external threats (for example, when giving orders) but who subsequently re-enter the group ( Critique, ). The concept of the mediating third party allows Sartre to extend his theory of interpersonal recognition beyond the fictionalized, abstract encounter between self and other, and better explain the fundamentals of group solidarity.
There’s definitely an element of Stoicism in existentialism, particularly in Sartre, and also in Viktor Frankl’s work. The difference is that there is more emphasis on the need for human beings to find a meaning and an individual purpose in what they do. It’s not just a matter of enduring or retreating into an inner realm in which you’re free. In fact, it’s not really about the inner realm at all, because the way you find meaning is not within, but through a purpose in the world, something that’s outside you, something that is greater than you. It could be by creating something, and it could be — and very often is — connections to other human beings, whether it’s comrades, friends, family or the people you come up against in life. And if all else fails — as it tended to in the concentration camps — and all the usual sources of meaning fall apart, there is always the chance of finding a meaning in the suffering itself. This is something that’s very hard to talk about in the abstract, but that was the conclusion that he came to.