[A] planet, wholly inhabited by spiders, (which is very possible)

I think you'll find it's a bit more complicated than that.

To disbelieve is easy; to scoff is simple; to have faith is harder.

Skepticism can keep us from blessing, can keep us trapped in two minds.

Believing everyone is dangerous, but believing nobody is more dangerous.

It is easier to debunk a thousand myths than to write one true sentence.

What we know here is very little, but what we are ignorant of is immense.

Take it with a whole shaker of salt, a grain won't be close to enough.

I believe that we do not know anything for certain, but everything probably.

You can feed a skeptic the party line but you can't make him swallow it.

She believed in nothing. Only her scepticism kept her from being an atheist.

What can be asserted without evidence can also be dismissed without evidence.

Superstition would seem to be simply cowardice in regard to the supernatural.

We need sentiment and skepticism. Sentiment to be happy; skepticism to be free.

To deny, to believe, and to doubt well, are to a man what the race is to a horse.