Physics for simples

So ive had this question for a long time and ive asked it to many and many have failed to grasp the concept of what im trying to say. Does a single point exist? how about a perfect circle? are they not just concepts available only in our minds? are they the same thing anyways? if you magnify a circle then no matter how close you get with our technology you can make out the particles that make up the shape. so the edge of the circle really is just a lumpy line when you get to close, so is there a line at all or just shapes? how about magnifying down to the subatomic level to find the smallest particle that exists and that takes up an infintesimally small volume and then classify that as a point. but even then at the subatomic level we have not scratched the surface of how infintesimally (big word did i spell that right?) more we could go. so the smallest particle known to man is still billions times bigger than the actuall smallest particle which we now know doesnt exist. so if the smallest particle doesnt exist what makes up the bigger particles? how can we classify space if we cant say how big things can get? maybe we'll learn that in the life to come. so here we are in our reality infintessimally small and also infintessimally large trying to find out if a circle can exist that fits our definition... i havent found one yet i think circles are not real except in our mind and i cant measure the circle in my mind so for all i know its so small it could be assumed to be a point but i can imaging the space inside so maybe its really big except its got to fit in my head right? to sum up what we dont know is this: perfect circles dont exist(probably) and mathematical points dont exist(that we know of). according to einstein we cannot know the exact location of an object, so a specific point, we can only know the speed that it has given the time or where it has been and you cant know both... so try not to think about this kind of thing for it only leaves you with answers that are satisfy your curiousity for the moment but lead to more questions and thus you are on the path to knowledge. or something else... let me know when you get there