Okay kiddo, let me explain the 'least dangerous assumption' to you. Have you ever heard someone say, "assume nothing or make no assumptions?" That's because sometimes when people assume things, they can be wrong and that can lead to really bad consequences.
So, the 'least dangerous assumption' means that when we have to make an assumption, we should try to choose the assumption that is most likely to be safe or least likely to cause harm if it ends up being wrong.
For example, let's say you're playing with a toy that someone left on the floor, and you assume that it's safe to step over it without looking. But the least dangerous assumption would be to assume that it's not safe to step over it, and instead make sure to pick it up or move it before walking by.
In other words, the least dangerous assumption is the one that minimizes risk and potential harm. It allows us to make informed decisions that protect us and others from harm, instead of taking unnecessary risks.