Perception is not truth. Truth is factual.

A object will fall at a certain rate, or it won't. CO2 absorbs infrared energy at a certain rate, etc. It's demonstrable, predictable, and repeatable.

It's also historical and factual. An event occurred or it didn't. You ran your car into a tree, or you didn't.

Telling your kid that you didn't run into that tree when you did is a lie, even though she may believe the source.

What you're saying is that your "truth" and what you believe depends on your sources.

But those sources can lie. And your personal view of the "truth" may be anything but.

Regardless, objects will still fall at a certain rate, CO2 will still absorb infrared energy at a certain rate, and so on.

Usually it doesn't matter too much if your "truth" deviates from the facts... but deviate too far, and the universe will often correct your viewpoint.

Sometimes violently.