Yes, but only in the more narrowly defined “givens of existence” sense. As in the deep human realities that come with being a conscious, mortal, meaning-seeking being.
In TST, existential givens are treated as a special subset of birth circumstances. Birth circumstances include the full range of starting conditions into which a person is born such as sex at birth, spacetime, parents, ancestry, first language, and first culture. Existential givens are the deeper human realities within that starting point: mortality, embodiment, separateness, freedom, responsibility, uncertainty, the search for meaning, and the absurdity of existence.
Existential givens are therefore not separate from circumstances, but they are not ordinary personal details either. They are the deepest layer of birth circumstances: the conditions that come with being born human at all. You did not choose to be mortal, embodied, separate from others, responsible for choices, or thrown into the search for meaning. But you can learn how to live with those givens, interpret them, respond to them, and let them shape your philosophy deliberately rather than unconsciously. This subset of birth circumstances is at the heart of existential philosophy.
In a real way, birth circumstances generally, and TST existential givens specifically, are a hook into existing philosophies. You can think of being-toward-death as a link into Heidegger’s existentialism, the absurdity of existence as a hook into Camus’ absurdism, freedom and responsibility as a bridge into Sartre, anxiety and inwardness as a link into Kierkegaard, and death, freedom, isolation, and meaninglessness as a modern bridge into Irvin Yalom’s existential psychotherapy.
TST therefore frames this topic through choice and constraint. Your life is not unlimited freedom, and it is not total determinism. It is a lived path through reality’s constraints, shaped by the circumstances around you and the existential givens within you.