Beware:

All too often,

We say

What we hear others say.

We think

What we are told that we think.

We see

What we are permitted to see.

Worse!

We see what we are told that we see.

Repetition and pride are the keys to this.

To hear and to see

Even an obvious lie

Again

And again and again

May be to say it,

Almost by reflex

Then to defend it

Because we have said it

And at last to embrace it

Because we've defended it.

-Octavia E Butler