Michael J. answered 03/13/19
GMAT, SAT, School Work, Bilingual English/Mandarin
There are a few problems I feel with each of the points individually, but in short I feel the main problem is the relationship between "motivates" and "cause " (point 3 and 4). Assuming we cannot comprehend of even fathom anything about the thought process of the insane, we can still observe, I.E. stimulate and observe reactions.
For example, I may not know what "motivation" an insane dog has to bite me after I kick it (I.E. probably anger or self defense but let's assume it's "insane" and thus we can't assume or postulate any type of mental/emotional stimulus) I can however ascertain reasonably that the cause of the dog biting me was me kicking it.
Unrelated side note: one of my favorite Robin Williams quotes is "we all have a spark of madness in us, we mustn't lose it." so maybe we all have a slight ability to understand even the "mad" or "insane".

Michael J.
03/13/19