First off: If you have no doubts in your life, then this is not for you.
That being said, I’ve seen the quote “doubt your doubts” floating around, and I’d like to address some conflicts I have with it.
Doubts are healthy, but if left unaddressed or added to, they can become very unhealthy.
If you truly DO doubt something in your life, I’d urge you to address it. If you let doubt linger it will fester and infect your happiness, eating away at it. And “doubting your doubts” will only compound the problem and increase the festering and doubt.
Addressing doubt will help you, not hurt you.
If you indiscriminately investigate your doubts and come to the conclusion that they are unfounded, it will set your mind at peace and you will be free of doubts dragging you down. Additionally, it will solidify what you believe and increase what you know because of that thorough and indiscriminating investigation.
If, on the off chance, you find that the doubts were warranted, you will be more enlightened about yourself and the world around you — even if it means you have to change yourself or something you believe. And even then, you will find yourself happier because doubt will no longer eat at you and drag you down.
Either way, addressing doubt will lead only to happiness and growth — whereas ignoring them can lead to worse issues and an unhealthy mental state.