The state you are experiencing now is determined by a combination of factors, including the initial conditions of the system you are observing, the interactions and measurements that have occurred, and the probabilistic nature of quantum mechanics.
In quantum mechanics, the state of a system is typically described by a wave function, which contains information about the probabilities of different outcomes when a measurement is made. The act of measuring a quantum system causes a collapse of the wave function, resulting in a specific outcome or state being observed. This collapse is described by the measurement postulate in quantum mechanics.
The specific outcome you observe at any given moment is determined by the probabilities encoded in the wave function of the system prior to the measurement. The probabilities themselves arise from the interaction of the system with its environment and the laws of quantum mechanics. The act of measurement selects one particular state from the range of potential states, and the probability of observing a particular state depends on the initial conditions and the dynamics of the system.
It's important to note that quantum mechanics is inherently probabilistic, and even if you repeat the measurement on an identical system, you may get different outcomes due to the probabilistic nature of the theory. The specific state you experience at any given time is a result of a combination of these factors and the measurement process itself.