I will give a talk on Confucianism

The use of prepositions in English can convey different shades of meaning. Take the use of 'on' and 'about' for example. When we say "The speaker will give a talk on drug abuse among the youth.', he will talk in detail how this happens, its causes and ways to overcome the problem. On the other hand, if we say "The speaker will talk about drug abuse among the youth.', he will talk briefly about the problem without going into details.

Hence, the preposition 'on' convey detaiedl treatment of a subject after it and the preposition 'about' in front of a subject will tell us that no detailed treatment of it will be done.

Can you tell the difference between these two sentences?
a) I will give a talk on Confucianism.
b) I will give a talk about Confucianism.