There is such a thing as objective reality
I think one of the most important axioms that one must internalize in order to navigate the world with thoughtfulness and rationality is that there is such a thing as a shared, objective truth.
The shared assumption that naturally occurring, observable, measurable, reportable, and verifiable facts actually exist and can be communally homed into despite one’s bias, perspective, or imperfect observation is the absolute bedrock of science; but it must also drive our civic discourse if rationality is to survive.
Influencers, religious hucksters, and propagandists—and even science video makers—continually try to convince you that there are infinite layers of alternative truths, alternative universes, alternative perspectives, that are all equally good; but the fact is that for the great majority of things that we deal with, there are not that many ways of looking at an occurrence. Usually, a coherent, factual, and independently verifiable explanation is quite readily available.
There is a great deal of money and influence to be made in telling people not to trust science, journalism, or expertise. Sometimes these folks are right. But the great, great majority of the time, they’re bullshitting you.
Quantum physics channels are notorious for doing this. They clickbait you with titles like ooh things are unknowable and spooky and how do you even know you’re real and energy isn’t even real, man or what have you, but most of the time, the effects they’re describing are so subtle that they are inconsequential to everyone except those who study the field, and even for them, they often exist only in equations, and have little physical analogs, certainly nothing that should affect your daily decision-making. Even formerly spooky behavior like tunnelling often turn out to be entirely mundane, and now you’re reading this on a device that uses this are particles even real effect like it’s a predictable, measurable, physical phenomenon—because it is.
All this is to say that we should hold fast to the idea that we live in a shared, objective, factual, measurable reality, and that this is a good assumption to have the vast, vast majority of the time, and that exceptions to this rule are basically nonexistent unless you’re a layperson who has somehow found yourself talking about a field of study you don’t understand.
All this is also to say that we should refuse “alternative facts” because they are absurd, useless, or harmful, and call them what they are: bullshit lies. We should eject them from rational discourse, denounce them as intellectual garbage, and give them no credence. They are the tools of charlatans.
All this is also to say that the words I don’t know is a perfectly good way to describe something one doesn’t actually know, and that we should all learn to appreciate such honesty.