Actually, he is mistaken...his is arguing from the absence of the
definite article in greek (sorta like our 'the'), but does not realize
that the absence of it does NOT IMPLY the presence of the indefinite
article (english:: 'a')...the greek HAD an indefinite article that it could
have used there, IF IT WERE trying to make the notion of 'a' beginning
clear ("in ONE beginning")...
The work 'beginning' falls into a class of semi-proper class nouns, like
'flesh' or 'law' that is translated with a 'the' AS LONG AS the
indefinite article/pronoun is not used...
The student-friend has perhaps not gotten to those lessons in his/her
Plus, for what its worth:
hope this helps...glenn