I saw a youtube video '4th dimension explained by a high school student' . I was very dissapointed in his concept of dimensions. First of all, we do see objects in three dimensions, the view that 3D vision is sort of an X ray vision is false. If an object is not 3D , it would not exist, firstly, where the word exist denotes  'matter in this universe' . When you see a face, you see all three variants of its build, that are the two lengths and the width. I hope the concept of dimensions is clear now.

Interesting fact about the theory of probability. If the probability of an event occurring is 0 or 1, it is no longer a theory, it's a law. However, if the probability is a number in between these two, it is a theory.

There is no such thing as present. Time never stops. A present would exist if and only if time were to stop. Since we can count the word 'present' out of the context of time, we are left only with the past and the future. These two concepts are the only ones that exist in reality. It is interesting to note that we live in the future, and 'have' lived in the past. Past is merely a previous future.