All your truths and beliefs are based on your perception, and your perception is a combination of 1)the data your senses decode from the environment, 2) an inner-feeling of rightness or wrongness (in your heart or your gut), and 3) the programming/conditioning of your awareness through the influence of your individual habits and experiences, and what you've been told by the authoritative voices of society.
But your senses could be faulty or limited; your heart/gut feelings could be influenced by your thoughts and thus the present conditioning of your mind; and all the authorities could be wrong too... or lying to you.
As much as you think you know, as much as everyone thinks they know, whether layman, expert, scientist, spiritualist, mystic, professor, parent or alien-abductee...
we could all be wrong. Everything could be illusion.
So what's real? What's true? Well, whatever you want, whatever you choose. Because if it's all illusion and everyone could be wrong, then you may just as well choose what makes you happy.
You have the freedom to do that.
But then freedom could also be an illusion - unless you choose to believe it's not.
And I could be wrong about that.
We could all be wrong.
But then again... we could all be right.