I'm assuming that pokeball are like star trek transporters. And that Pokemon is actually a sci find world where the pokeballs turn the Pokemon into code and stores them inside until you send them back out. Hence the white light upon entrance.
Now inside I'm guessing while they're in the code they can be in whatever world they imagine inside or something. Or a world that is programmed into the balls. And there why. Certain pokeballs have a better catch chance because then programming is better.
Now the fact that humans can survive 1000 degree burns from Charizard and getting electrocuted by lightning constantly says that they are also Pokemon just like we are also mammals.
Now inside I'm guessing while they're in the code they can be in whatever world they imagine inside or something. Or a world that is programmed into the balls. And there why. Certain pokeballs have a better catch chance because then programming is better.
Now the fact that humans can survive 1000 degree burns from Charizard and getting electrocuted by lightning constantly says that they are also Pokemon just like we are also mammals.