“Is” is often equated with “true”, “the truth”, “facts”, “exists”, and “verifiably true”. Which is why I have no patience with liars (e.g., Trump: over 16,000 lies and misrepresentations since taking power over 3 years ago). He has lied throughout his presidency, during the impeachment proceedings, and afterward; he is incorrigible, “fake news”, horribly misleading and distracting, and simply full of b.s. all the way.
More basically, I would say that “exists” and “true” (as in verifiable to self and others) constitute a possible foundation for viewing and understanding many things in life. Often there is a blend of common sense, objective fact and reason to this process. Things get confusing, though, when the O’Briens (Trumps) of the world hold up a perceivable number of fingers and tell some poor schmoe like Winston Smith that he can’t believe his eyes. Instead, he must believe his ears and the toxin that the dictators pour into them unfiltered.
So an individual will be o.k., sane, and potentially smart and ungullible if s/he believes the evidence of the senses along with other mind-processed evidence without the obstruction and interference of a third party, especially with obvious agendas.
Potentially, an individual has the capacity for realizing truth, fact, and existence from unblinkered, unagenda-ed (including personal) perception and evidential correspondence from experience, close critical reading, a well-rounded education, and established facts.
What “is”, exists, and is true, ultimately, comes from the best available information an individual has along with a series of perspectived contexts to view that info in/against.
The worst trend of the Trump era is to deny all the above and to ignorantly believe in and adhere to sheer agenda-ed crap foisted on people whose education is low or incomplete in the wider scope of sane, rational, and common-sensical public argument.
There are many truths in life, especially as an individual finds out, emanating from inside and outside, but one must needs have an evolving crap detector to fend off the fake news, fictitious narratives, and unabashed propaganda (including feel-good advertising) of our time.
There are also both subjective and objective truths, and those larger, more universal truths (Truth) that emerge when there is a corresponding truth between the two. For all the alternative brainwashed rubes on the “other side”, though, there is not much hope except for a lemming-like plunge off a mindless cliff in some Nowhere Land.
“Orthodoxy means not thinking–not needing to think. Orthodoxy is unconsciousness.”
“To see what is in front of one’s nose needs a constant struggle.”
“Reality is inside the skull.”
“There was truth and there was untruth, and if you clung to the truth, even against the whole world, you were not mad.”
“In a time of deceit telling the truth is a revolutionary act.”