first you would have determine what is the basic unit of a thing, or a concept in this case. then, even if you know something and explain it in its arbitrary defined unity, how are you certain that the explanation you gave is corresponding to the concept you're thinking of? you probably would have the feeling that your explanation is correct, but is a feeling enough as a proof?
so "truth" lies in "being", there is being, then there is truth spawned as a feeling
1+1=2 gives me the feeling that this is true, but is my feeling really connected to the equation? what is "being connected", and then what is the thing that defines connection?
i only go deeper and deeper, and eventually i see no hard ground but only void, "truth" doesn't exist, there is only being