The "provisional existence of unknown limit" means that the concentration camp inmates had no idea how long their sentence would be. A normal prisoner knows how long their sentence is—one year, two years, five years, and so on—and can plan for a future after the "provisional existence" of prison ends. The lager inmate, however, could make no plans for the future because of not knowing when the future after the camp would begin. This placed a special psychological burden on the prisoner, which Frankl likened to unemployed workers living in a limbo of not knowing when or if they would ever have a job again.
The "time experience" the inmates experience is connected to the provisionality because of the sense of limbo the provisionality caused. A day seemed endless because of all the small, endless tortures, but a week would fly by as if it hadn't happened. Frankl said it was important to fight back against the feeling that the provisional existence was "unreal" because the unreality could make you feel as if you were dead. As Frankl states:
Regarding our "provisional existence" as unreal was in itself an important factor in causing the prisoners to lose their hold on life; everything in a way became pointless.
Instead of this attitude of life as pointless, Frankl suggests it was important to stay in the here and now and see the present as an opportunity for inner spiritual growth.