Answer:
What Cadalso criticizes of these "falsos eruditos" is that in reality they are vain and charlatans who appear to be wise but know very little.
Explanation:
Cadalso believed that it was impossible to change a society completely and that false erudites when faced with serious people fail to do so.
This problem has always existed, and those who think they are erudites really are not, they only appear to be intelligent on the outside and inside they know nothing.
According to Cadalso today what "makes you an erudite" is "to understand French moderately, to frequent public entertainment, to gossip about antiquity and to affect lightness in the most profound matters".