Our doubts are traitors,
and make us lose the good we oft might win,
by fearing to attempt.

We, ignorant of ourselves,
Beg often our own harms, which the wise powers
Deny us for our good; so find we profit
By losing of our prayers.

The danger is that in reaction to abuses and distortions of an idea, we'll reject it completely. And in the process miss out on the good of it, the worth of it, the truth of it.

When I consider Life, 'tis all a cheat;
Yet, fooled with hope, men favour the deceit;
Trust on, and think to-morrow will repay:
To-morrow's falser than the former day;
Lies worse; and while it says, we shall be blest
With some new joys, cuts off what we possesst.

That was the danger. Not that betrayals happened, not that cruel things happened, but that they could outweigh all the good. That we could forget the good and only remember the bad.

All that denies must be torn out and slain
And crushed the many longings for whose sake
We lose the One for whom our lives were made.

03.02_082:010

[I]t is that we are too apt to despise what appears to be neither good nor beautiful, and thus we lose what is helpful and salutary.

Men of ill judgment oft ignore the good that lies within their hands, till they have lost it.

It is not only the hostility of others that may prevent us from questioning the status quo. Our will to doubt can be just as powerfully sapped by an internal sense that societal conventions must have a sound basis, even if we are not sure exactly what this may be, because they have been adhered to by a great many people for a long time. It seems implausible that our society could be gravely mistaken in its beliefs, and at the same time, that we would be alone in noticing the fact. We stifle our doubts, and follow the flock, because we cannot conceive of ourselves as pioneers of hitherto unknown difficult truths. It is for help in overcoming our meekness that we can turn to the philosopher.

Do not forget that a traitor within our ranks, known to us, can do more harm to the enemy than a loyal man can do good to us.

Knowledge often spoils devotion.

You need to remember that your excuses are seducers, your fears are liars and your doubts are thieves.

sometimes i lose faith in human nature for a time; i am assailed by doubt.

Tis safter to be that which we destroy
Than by destruction dwell in doubtful joy.