The fact that reality constantly changes (or is one thing eternally the same, depending on your point of view), doesn't mean that men cannot at least get an approximate grasp on how it changes...if you don't believe, though, that there is such a thing as objective reality, though, then, you are right in disregarding the work of scientists who have done their best to objectively explain how things work. If that is the case, though, then there are all kinds of moral problems thrown up, especially with regards to how we interact with other people, and how our personal realities affect theirs, if at all.
I think reality is objective and subjective and much more alternate and infinite than anyone could ever dream. I've had a vision of physics that shows the connection of all things and how even the slightest exercises of will can directly influence and alter anything and everything if shaped and sent forward in a lucky or intelligent and knowledgable manner. The manifestation and transformation of all matter and the causes and effects of all manifestations and transformations that create all observable phenomenons is readily and easily available and predictable from a simple model I have devised explaining the beginnings and origin of creations. From the immortal observable beginnings of infinite creations things get a little more complex, but it is curious how the causes and effects of the more complicated dances and interactions of greater masses of finite particles of infinite potential return to the simple harmonies of their simpler and singular beginnings. Using this knowledge makes understanding the expansion of the Universe simple. Gravity is clearly revealed. Creation is revealed to be immortal and indestructable with no ends and no beginnings and with no bounds.