That which is perceivable to us is not the “things in themselves” — we have absolutely no access to that — but rather ourselves (and/or our extensions of ourselves via our instruments, more about that below) in relationship to the “things”.
You familiar with astronomy and the concept of parallax? The location of a celestial object appears to move against the backdrop of more distant objects as a function of whether the earth is at the winter end or the summer end of its orbit, that variation in observer-location being sufficient to change the viewing angle. A parsec is the distance at which a celestial object would have a parallax of one second of arc, and so on. Yes?
Use that as a metaphor. “Things” that are “close to us” — emotionally, culturally, experientially, historically, personally, as well as physically —may be perceived differently by different people. The “thing” has that meaning to the person for whom it has that meaning but only through communication and learning how to perceive the “thing” as others who are differently situationed experience it can we assemble a “view” of the “thing” that takes all these different “subjective views” into account.
And yet the “things” that are not close to us don’t truly lack that characteristic (any more than some way-distant galaxy billions of light years away from us truly lacks parallax) — it’s just that in some meaningful sense the total range of human experiences and perspectives on those “things” differs so little — the parallax is so infinitesimally small — that we lose nothing by ignoring it.
When I’m driving from New York to Georgia, I make use of maps that pretend that the earth is a flat-planed surface. I know that I’m actually traveling along the exterior skin of a sphere but taking that into account just obfuscates the clarify of routes and travel plans, it adds nothing useful. Were I to be flying a plane to Kamchatka, matters would be different. In a similar fashion, pretending than an “objective” world exists (in the sense of being available to us) is not just a semi-accurate shorthand, it’s a highly useful shorthand that enables clearer and easier thinking than dubbing in this awareness of how our perceptions are always, unavoidably, intractably subjective. Because for one reason or another (including the use of scientific method and technological instrumentation) the “parallax” is so small we’re best off ignoring it.
Now I said I’d return to the matter of our instruments and so forth. I just now said our perceptions remain subjective. And they do. And at the top I said what we perceive is ourselves in relationship to “things”, and it is perhaps useful and necessary here to point out that when we make use of an instrument, we experience the instrument, we experience what the instrument can tell us, and it is still ourselves in relationship to “things” that forms the ground of all that we can know. What science and measuring devices et al do for us is not to erase subjectivity but to provide us collectively with a way of experiencing things that is more consistent and reliably repeatable than our ways of experiencing them otherwise. Our experiences of our own devices and our scientific experiments’ observable data and so on are useful to us to the extent that they help to reduce the “parallax” of the underlying subject area we’re studying. (This is true in the larger sense even when in the immediate sense an experiment or an instrumental measurement makes a distinction between “things” that previously looked identical to all human observers. In the long run, and as the perception is integrated into the rest of what we think we know, it works to give us all a more unified, less “parallax”-dependent vision of the world in which we live).