Thanks Grammar Geek, Renan & Kooyen!
So it could, technically go both ways, since THE DIRECTION AND PURPOSE could be taken either as singular or plural...
My instincts tell me the sentence with HAS and OWES sounds better too.
@ Renan: I'll give your version consideration. thanks! Although in your sentence I'd change "in a great deal" to "to a great/large extent"
I actually translated this sentence from a French sentence which is even more grammatically thorny because of the rule of gender and plurality agreement when the direct object complement (complément d'objet direct) is placed before the past participle with the use of the auxillary verb 'avoir' with 'passé composé' conjugation... horrible confusing rule:
which means I'm not sure whether it should be:
La direction et le sens qu'a pris ma vie depuis mes études à l'institut doit beaucoup à l'enseignement du Professeur E.
or
La direction et le sens qu'ont pris ma vie depuis mes études à l'institut doivent beaucoup à l'enseignement....
or
La direction et le sens qu'a pris ma vie depuis mes études doivent beaucoup...
but I guess this is not the right forum for that particular prickly pear!
Thanks again to all!