Further, you understand the origin, nature and purpose of scientific instruments, from the magnifying glass to the computer to the LHC; you have a useful outline of medicine and biology, you aren't perplexed to know how flowers grow from seeds or tadpoles from spawn, or to read a report on brain research. You live and function in, and understand, a world where knowledge isn't absolute, yet good enough to put rovers on Mars, make medicines for certain brain disorders, treat Ebola, aid fertility &c, create new materials, on and on.
So my point is that there can indeed be a legitimate and functional concept of truth in your world and in mine. Do you seriously dispute that?