Because up and down are two directions they literally cannot be confused for one another. Up is always towards the sky or ceiling, down is always towards the floor. You have to intimately understand those concepts to be a functioning human being such as walking and moving. Left and right are not descriptors of really anything, while up and down are obvious general things while also being opposites. Very hard to confuse opposites but very easy to confuse two options that are generally the exact same other than name like left and right.
Latest Answers