Two Levels Of Kedusha

 The Ramchal in hakdamah to מאמר ויכוח:

The Ramchal delineates two approaches to kedusha.  The peshat approach is that kedusha means separation as Rashi in the beginning of Kedoshim says.  The Kabbalist on the other hand does not see the pleasures of the world as a negative that must be avoided but instead elevates the world around him and infuses it with spirituality.  It is interesting that in the Mesillat Yesharim the Ramchal calls the peshat of kedusha the level of taharah and calls the level of  kedusha the Kabbalist approach to kedusha.

According to Chassidus based upon the Arizal, the function of our life is to be able to be מעלה fallen ניצוצות (see מעולפת ספירים.)  In the sefer אלו ואלו דברים אלקים חיים by Rav Tzvi Einfeld he demonstrates that the Gra was not a fan of practical application of this concept.  Getting involved in the elevation of hidden sparks of holiness brings one too close to the boundaries of tumah and can cause one to fall.  

It would seem these two approaches mirror the levels of kedusha that the Ramchal speaks about.  The Gra advocated for the peshat approach.  He practiced austerity and viewed the external world as a threat to maintaining one's holiness.  The Chassidim advocated the Kabbalistic approach and viewed the general world as something which can be elevated.    

It would seem to a casual observer that these two approaches are reflected by many hashkafic debates that have raged from the early 20th century until today as to how much one should protect Judaism as an insular system or can one find positives in movements that are non- Torah based.