That people in different situations will experience different things that will have different influences on what they know to be true. For example if someone sees something and tells someone else what happened, the reciever might not think the messenger is telling the truth. The messenger can describe with lots and lots of vivid details about what they saw, but since the reciever didn't see what might have actually happened they just won't believe the messenger. This is because it's the first hand experience that makes all the difference on somebody's way of thinking.
An influence can be something a person sees, hears, smells, tastes, or feels.
Example for how taste is an influence - Suppose two different people travel to Mexico at the same time, they have the same itenerary, they see the same things, and eat the same food. They both go to the same resturant and order the same burrito. One of the two people claims the burrito was too spicy and was no good. The other person says it was the best burrito they had ever had, (also suppose one person just doesn't like the rest of the food while in Mexico, but the other loves it.) When the food hater's asked, "How was your trip in Mexico?" Hypothetically they could respond, "Ugh, it was awful. The food was terribly spicy." But when the food lover gets asked the same question they could hypothetically respond, "It was amazing! The food was just perfect!"
See how taste can influence somebody's experience. One person's experience was way better than the others just because of the food they ate. And nobody can tell the two travelers that there opinion on Mexico is wrong, because when the travelers went that had different experiences in Mexico. And when two people have different opinions they aren't wrong. It just means that the two people are different. And people are allowed to be different, but that also means people can judge other's and not stop them. Somebody could judge the food hater to be a crazy person just like how somebody could judge the food lover to be a crazy person. But the two travelers have their own reasons for why they did or didn't like their expierence in Mexico, and that's what counts.