This is in the field of sociology?
"Reflection" implies the act of thinking, or a single thought. If you mean that your entire dissertation contains multiple thoughts on this topic, then "Reflections" might be better.
You're trying to make it more active by not using nouns, which is normally a great idea, but in this case I'm afraid it changes the meaning slightly; I'd go with nouns and make it "... on the finding and invention of realities".
(Though "finding" is ambiguous; do you mean the seeking or the discovery?)
("Realities" is nonsense in normal English, but correct in the social sciences, in case anyone objects!)
-- Crossposted with Braunbärin but I see we agree. The capitalisation depends on whether you want AE or BE.