As an expert on fiction texts, you have been asked to address the above statement to a group of HSC candidates in connection to their text 'The Lovely Bones' by Alice Sebold
I think this is a statement that can easily be supported with reference to this excellent novel and in particular, the way that the author has chosen to narrate the tale from the perspective of a character who dies very quickly in the novel and looks down on the rest of the action from her vantage point in heaven. The ideas and issues of death and grief and how those who are left behind have to wrestle with such concepts thus shape the novel to a tremendous extent.
What I believe you are asking is about narrative perceptions. Therefore, as in the novel The Lovely Bones, narration is very important when dealing with issues only the person to which they are happening to can offer the most honest and insightful perspective possible.
The novel could not have been written in any other perspective but first-person. Readers need to be able to trust in the speaker, what the speaker is saying, and how the speaker feels. Without the direct line to the speaker's emotions, the novel would lack the intimacy needed to capture readers emotionally.
If written in second person or third person, the novel would lack the intimate details which makes the novel what it is...a play on the emotions of the reader.
If a speaker, or narrator, does not have first hand knowledge of the ideas and issues being explored in the text, readers will not consider them to be trustworthy. What the speaker is saying would be considered a simple understanding of something, not of an experience which they truly lived.
It is only through first-hand experience with which people familiar with an idea or issue can relate to others in the same situation.