Paul Graham has a wonderful essay online, reading time approximately 10 minutes: Lies We Tell Kids
(The essay was brought to my notice via overcomingbias.com)
Some quotes:
This sentence is gold:
The truth is common property. You can’t distinguish your group by doing things that are rational, and believing things that are true. If you want to set yourself apart from other people, you have to do things that are arbitrary, and believe things that are false.
And here:
We arrive at adulthood with a kind of truth debt. We were told a lot of lies to get us (and our parents) through our childhood. Some may have been necessary. Some probably weren’t. But we all arrive at adulthood with heads full of lies.
There’s never a point where the adults sit you down and explain all the lies they told you. They’ve forgotten most of them. So if you’re going to clear these lies out of your head, you’re going to have to do it yourself.
Few do. Most people go through life with bits of packing material adhering to their minds and never know it. You probably never can completely undo the effects of lies you were told as a kid, but it’s worth trying. I’ve found that whenever I’ve been able to undo a lie I was told, a lot of other things fell into place.
I have to absolutely second the last sentence – the most gratifiying experience when adopting a scientific mindset – or, more strongly, adopting a scientific identity – is the freedom to systematically discard the fantasies underlying your local group (nationality, ethnicity, religion, what have you…) world view: and from that point on the world starts to make more sense every day!
It’s not enough to consider your mind a blank slate. You have to consciously erase it.
It reminds me of something which I said in a lecture half a year ago: before starting to learn things, you have to unlearn most of that which you think you know (because it is false). The “knowledge” base existing in our brains is probably the biggest barrier to erkenntnis (insight, knowledge, truth) we face.
Happy cognitive deleting 
