To know a person, one has to get involved with him. One has to walk with him and share his experiences. Involvement is a two-way process. We cannot share the experiences of an Other if he closes himself from us. Neither can we force ourselves on him.
Involvement can only happen in the context of a relationship.
The person is the access to truth. But it doesn't mean that the person is only a means to truth. The person is always an end in himself, but it is only as persons that we can walk together towards the truth. Allow me to explain this idea with a story. When God decided to dwell among men, he asked the angels where he should live.