all affairs, it’s a healthy thing now and then to hang a question mark on the things you have long taken for granted. — BERTRAND RUSSELL,

It's always time to question what has become standard and established.

Wondering’s healthy. Broadens the mind. Opens you up to all sorts of stray thoughts and possibilities.

Honest differences are often a healthy sign of progress.

Pour examiner la vérité, il est besoin, une fois dans sa vie, de mettre toutes choses en doute autant qu’il se peut.

When it comes to life the critical thing is whether you take things for granted or take them with gratitude.

Try your hardest to combat atrophy and routine. To question The Obvious and the given is an essential element of the maxim 'de omnius dubitandum' [All is to be doubted].

Health and understanding seem to intersect in one’s forties, the one peaking as the other begins its slow ascent. Maybe you’ll know one day what you should’ve taken the time to appreciate.

Good that you ask — you should always ask, always have doubts.

There is no harm in doubt and skepticism, for it is through these that new discoveries are made.

The plain working truth is that it is not only good for people to be shocked occasionally, but absolutely necessary to the progress of society that they should be shocked pretty often.

We should probably all pause to confront our past from time to time, because it changes its meaning as our circumstances alter.

Digressions, objections, delight in mockery, carefree mistrust are signs of health...

The relationship between commitment and doubt is by no means an antagonistic one. Commitment is healthiest when it is not without doubt, but in spite of doubt. (p. 21)