If you want to stay in for the long haul, and lead a life that is free from illusions either propagated by you or embraced by you, then I suggest you learn to recognize and avoid the symptoms of the zealot and the person who knows he is right. For the dissenter, the skeptical mentality is at least as important as any armor of principle.
Interpretation
Embrace skepticism to avoid delusions and maintain a clear perspective on truth.
Christopher Hitchens emphasizes the importance of skepticism and self-awareness in leading a fulfilling and honest life. He argues that to avoid being misled by one's own beliefs or by the beliefs of others, one must cultivate the ability to question and critically analyze assumptions, particularly those that may lead to dogmatism or zealotry.
In practice
During a debate on beliefs, you might quote Hitchens to encourage critical thinking.
In a public dialogue with Salman in London he [Edward Said] had once described the Palestinian plight as one where his people, expelled and dispossessed by Jewish victors, were in the unique historical position of being 'the victims of the victims': there was something quasi-Christian, I thought, in the apparent humility of that statement.
What can be asserted without evidence can be dismissed without evidence.
Never ask while you are doing it if what you are doing is fun. Don't introduce even your most reliably witty acquaintance as someone who will set the table on a roar.
[E]xceptional claims demand exceptional evidence.
The worst days are when you feel foggy in the head - chemo-brain they call it. It's awful because you feel boring. As well as bored. And stupid. And resigned.
Let me tell you something: for hundreds of thousands of years, this kind of discussion would have been impossible to have, or those like us would have been having it at the risk of our lives. Religion now comes to us in this smiley-face, ingratiating way — because it’s had to give so much more ground and because we know so much more. But you’ve got no right to forget the way it behaved when it was strong, and when it really did believe that it had God on its side.
When you find peace within, you also find that you can do without. This means simply that you no longer need the things of your outside world, and not needing is a great freedom.
We are all geniuses up to the age of ten.
It is right that we should stand by and act on our principles; but not right to hold them in obstinate blindness, or retain them when proved to be erroneous.
Victory puts us on a level with heaven.
It hurt, of course, but more often than not the best things do, I've found.
The melancholy joys of evils pass'd, For he who much has suffer'd, much will know.
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