The use of 'ses'

Question

In the phrase, "...il faut défendre ses opinions", why do the French use 'ses'?  I would have expected 'vos', i.e. it is necessary to defende YOUR opinions.  Is it simply the way the French express this allusion to others?

Accepted Answer

Hi Frank, 
Because il faut is used and as it is a general statement the correct possessive adjectives to use is 'ses'.
It is a rare case when I would translate it as one's 
Il faut défendre ses opinions = It is necessary to defend one's opininions
could have been 
On doit défendre ses opinions 
as opposed to 
Vous devez défendre vos opinions = You have to defend your opinions
Hope this helps!

Answer

Hi Frank,It's the plural of their(s) in English.son (nm) sa (nf) ses (npl)      third person plural, but you are expecting second person plural?"il faut défendre ses opinions" -->    "It is necessary to defend your? or their? options"Bonne journéeJim