Sentence:  I speak of `` the largest possible <WSD>measure</WSD> '' because any person who supposes that these conditions can be universally and perfectly achieved - ever - reckons without the inherent imperfectability of himself and his fellow human beings , and is therefore a dangerous man to have around . 
Meaning of the word marked with <WSD> tags:  how much there is or how many there are of something that you can quantify