Do not we call the past, the future and the present because there is a comparison? What is the comparison? memory / MEMORY.
Everything that is in our memory that we call the past alias was never experienced.
So then, the future is everything that is not in our memory yet.
Between the concept of the past and the future we call it now. Well let's suppose. If humans do not have the ability to save memory, is there such a thing as past? No is not it? And since nothing is stored in memory then there is no future. Yeah tho? Because there is no comparison.
Another consequence, if there is no memory then there is only now !!!