Tu parles moins que je ne le pensais.

Question

Why is pas not used in this example? "...je ne le pensais pas"? What is the concept/rule that I'm missing here? Tu parles moins que je ne le pensais.Source - https://french.kwiziq.com/revision/glossary/grammatical-form/le-comparatif-comparative

Accepted Answer

Aashpreet, 
below a few links on ‘ ne explétif ‘ and the neuter object pronoun ‘ le ‘, which are both evident in this construct. 
Ne explétif can be used with comparisons of inequality, amongst other uses, but has no specific meaning in its own right, and is optional, particularly in spoken French. Importantly this is not a negation of the verb  ‘ penser ‘ and ‘ pas ‘ is not part of the construct.
The neuter object pronoun is used in association with a number of verbs, of which penser is a common one.
 
https://progress.lawlessfrench.com/revision/glossary/sentence-types-forms/ne-expletif-expletive-ne 
https://www.lawlessfrench.com/grammar/neuter-object-pronoun/
 https://www.lawlessfrench.com/grammar/ne-expletif/

Answer

Thank you.