When discussing in Indian philosophy the snake/rope confusion we need to strictly distinguish it from an illusion. An illusion stays an illusion even when you know that it is one. The Muller-Lyer lines still continue to look unequal. Adalbert Ames’s illusions are uncannily persistent.ames room
The rope is no longer seen as a snake when we discover our mistake and that is an important epistemological point in Indian philosophy. In the Nyaya inflected account of the advaitin Dharmaraja Adhvarindra our default position re perception is to accept it as veridical until shown not to be on further acquaintance.
He writes in the section The validity of Knowledge is Intrinsic and Self-Evident of the chapter on Non-Apprehension:
The validity of knowledge generated by the above -mentioned means of knowledge originates by itself and is self-evident. To explain: Valid knowledge is that knowledge regarding something possessing a particular attribute, which has that attribute as its feature which is conducive to successful effort, and which includes recollection as well as fresh experience.
The term ‘effort’ refers to the factor of confirmation. The silver we pick up is precious and not a mere piece of nacre. Unsuccessful effort is to discover on closer examination that we were suffering from temporary confusion. Clearly this is different from illusion.