Correct, but not cause for despair, which I feel is implied here. I also feel like you imply that "pure" positivistic, formalist knowledge is the unattainable ideal that we must aspire to. Like you, I feel that we, as a society, as a species, are worse off for our lack of mutual understandings. However, you are focused on thought and language as the only means by which these understandings are attainable. There is no universal reality to find, but rather, there are multiple realities, some of which overlap, some of which do not, most of which are mediated constructs. It is these constructs that interfere with mutual understanding, not "biological differences." We may never be able to fully communicate our experiences with each other, but we can still do so in many meaningful way where realities intersect. We increase the likelihood of creating these intersections by practicing the component skills that comprise empathy. I would go one step further by stating that it may not even be desirable for two people to ever have a perfect, pure, empirical understand of each others' experience. Were that to occur, it would require the total dissolution of the self, so that self and other cease to exist. I am no metaphysician, but my guess is that we are all destined to have this experience upon the expiration of our finite lives.