In all affairs it's a healthy thing now and then to hang a question mark on the things you have read more

In all affairs it's a healthy thing now and then to hang a question mark on the things you have long taken for granted.

Who never doubted, never half believed. Where doubt is, there truth is -- it is her shadow.

Who never doubted, never half believed. Where doubt is, there truth is -- it is her shadow.

The whole problem with the world is that fools and fanatics are always so certain of themselves, but wiser people read more

The whole problem with the world is that fools and fanatics are always so certain of themselves, but wiser people so full of doubts.

To have doubted one's own first principles, is the mark of a civilized man.

To have doubted one's own first principles, is the mark of a civilized man.

The road to perseverance lies by doubt.

The road to perseverance lies by doubt.

He who knows nothing, doubts nothing.

He who knows nothing, doubts nothing.

Laugh at yourself, but don't ever aim your doubt at yourself. Be bold. When you embark for strange places, don't read more

Laugh at yourself, but don't ever aim your doubt at yourself. Be bold. When you embark for strange places, don't leave any of yourself safely on shore. Have the nerve to go into unexplored territory.

There is nothing more dreadful than the habit of doubt. Doubt separates people. It is a poison that disintegrates friendships read more

There is nothing more dreadful than the habit of doubt. Doubt separates people. It is a poison that disintegrates friendships and breaks up pleasant relations. It is a thorn that irritates and hurts; it is a sword that kills.

Any belief worth having must survive doubt

Any belief worth having must survive doubt