So we have to come to a deeper understanding of how to explain what is going on in this

double-studed experiment because if we fire either a photon or an electron at that double-slide

apparatus and we put a detector at either of those slits, then we will detect a particle.

So we can detect that we fire a particle, we can detect that a particle is going through those slits

and we can detect a particle at the projection screen as well. When you do this experiment in the

laboratory using electrons, you can see the dots where the electrons strike hitting the screen.

But you don't get a simple pattern that you would expect. If you're firing cannonballs at a wall,

where there are two holes in the wall through which the cannonballs can go,

you would expect that all the cannonballs are going to go through those two holes and land in

one of two positions behind the wall. But with particles at the quantum level, that's not what

happens. Something is going on. And the only explanation is that when we fire a photon,

there's the photon that we can see in our universe, but there's also photons in other universes

passing through the apparatus that we cannot see. And these photons are able to interact with the

photon that we are able to detect. This is where the concept of interference comes in.

Interferences in old concept in physics. It goes back to waves, waves certainly interfere. But we

need to understand the way in which particles can interfere one with another. Particles that we

can observe and particles that we can only assume to observe given these experiments. And this is why

we are forced into acknowledging the existence of these other particles. And not only these other

particles, but other universes in which these particles exist.