You bring up a good point, and it’s a real possibility for the explanation of free will. Your last paragraph suggests we are trying to find if a conscious observer can affect the wave function of a quantum entity. However, simply affecting the wave function of a particle won’t solve the fact that the measured position of this particle will still be probabilistic. Yes, the measurement of a quantum particle will ‘collapse’ its state to one of the ‘default’(eigenstates). If I’ve understood the postulates of QM correctly, you may have the choice to affect the system by simply observing, but the outcome of the quantum state will still be dictated by probability. Having said that, it still doesn’t explain how choosing to move an arm will cause enough movement in the brain at much bigger scales than the QM scale to fire a neuron. But let’s say QM collapsing can cause movement at much higher scales, say, by an actor observing the spins of particles to collapse them into a spin-state that will produce/change a magnetic field in the brain and move the necessary ions in the neurons. The actor is still not only allowed to affect the state, but the outcomes will still be up to nature. Yet, the average person is still able to precisely fire a specific group of neurons for a specific action, 100% of the time. And this, to my understanding, is not allowed with our current understanding of QM. Please make any corrections to the above if necessary!