"uncertain existence" is a correct and usable phrase in written English.
You can use it to refer to something with an unclear future or outcome, like a job, an idea, or even a life. For example, "With the current economic climate, many of us have an uncertain existence, not knowing what the future may hold."
Those landmarks surrounded her uncertain existence, which has proved difficult to trace.
The fact that Latin American governments, themselves unstable, generally took charge of higher education explains in part its uncertain existence.
Despite the fame and glory they achieved, the far less glamorous and more uncertain existence of league soccer has abruptly returned.
"Just think, a father assassinated, becoming a target of the Taliban, al-Qa'ida, the ISI (Pakistani secret police) – it is a very uncertain existence," said Jawad Nasruddin, a political analyst".
Yet, despite the fame and glory the Americans achieved with their thrilling run at the World Cup, the far less glamorous and more uncertain existence of league soccer has abruptly returned.
A small family returns to Ireland from "over beyond" with a daughter now more used to speaking German; they eke out a hollow, uncertain existence in a show home on a half-finished estate, eating off picnic furniture and listlessly picking their way through the long summer days.
At the first step, using Lyapunov's direct method, a non-linear state feedback is selected so that without any need to apply identification techniques, in despite of the uncertain parameters existence in the system state equations, the asymptotic stability of the general Lorenz system is guaranteed in a stochastic point of the manifold containing general system equilibrium points.
The walls are built of brick-faced concrete, with a complicated system of relieving arches, corresponding to the chambers in the drum, which extend as far as the second row of coffers of the dome; the method of construction of the upper portion is somewhat uncertain (the existence of ribs cannot be proved), but is probably of horizontal courses of bricks gradually inclined inwards.
Palaeontologists had been uncertain about the existence of long-snouted tyrannosaurs.
In uncertain graphs, the existence of some edges is not predetermined.
The actual author of the tales remains as uncertain as the existence of the English knight Sir John Mandeville himself.
