In this interpretation what we think is indeterminacy is in fact created because of our inability to see certain ‘hidden’ aspects of particles. In hidden variables, you can say that particles exists as both particles and waves at the same time. There would be the normal particle and a so called pilot wave guiding the particle along its path. The wave then affect the particle with something called the quantum potential. For example in the double slit experiment: First the pilot wave goes through both slits just like explained above, this wave is the thing telling the particle were to go. It would create the interference pattern, and then the particle would go through one of the slits, it doesn’t matter which. Now the pilot wave would guide it to a spot on the screen, but the pilot wave has also created an interference patter and what we called the dark stripes is now the places were the particle won’t strike and the bright stripes were the particle will strike. At what point of the bright stripes the particle would strike is therefore determined by the pilot wave and not uncertain, but it changes from time to time.
However problems exist with the interpretation. It is non-local since the pilot wave have to know all information about the surrounding and measuring device instantly and transmit it to the particle instantly. No something alarming but think of this: When you measure a particle in the EPR experiment the wave function has to travel to the other particle so that the quantum potential can change it into the opposite spin. Even though this non-locality may not seem like such a bad thing since other interpretations like the Copenhagen also have it. But in the other interpretations the wave function isn’t something physical, it still allows for faster then light communication but the wave function isn’t real and doesn’t travel any were. But in hidden variables the wave function is a physical entity and there for it travels faster then light, which can be found unsettling. Another problem with the wave function as a physical thing is with reference frames which exist in the theory of relativity. In relativity things doesn’t happen in the same order as seen from different reference frames. So even though it may seem like the particles both gets defined spin when you measure one of them they may actually be measured in different orders in different reference frames, this creates a problem that if in your reference frame you measure one particle and then the wave function must travel toward the other particle. But as seen from another frame the particles may be measured in different order and so the wave function travels in the wrong direction so things happen in the wrong order. And also in classical physics a force also has a counter force in the opposite direction. Meaning that if the quantum potential exerts a force on the particle the particle would also exert a force on the quantum potential. But it doesn’t. And if it would exert a force on the particle order to change its path, then according to classical laws the particle would then reach i.g the screen in the interference experiment with a different amount of energy then it had from the beginning. And this isn’t observed to happen. So now it has been proposed that the pilot wave instead of exerting a force on the particle, sends information to the particle so that it knows were to go. Which seems to mean that the particle can somehow think.
But you shouldn’t rule out this interpretation because of this. There is no direct proof that forbids a hidden variables interpretation.