As I understand the Gospel records, Mr E. Keane (May 13) is perfectly right in thinking that Our Lord after his Resurrection could have been "seen by non-believers if they had been present."
And this for the simple reason that, according to St Luke and St John, the risen Lord was seen by non-believers: for both evangelists tell us of post-Resurrection appearances of Jesus which led the persons who received them from non-belief to belief — implying that when he first came into view the beholder (or beholders) in question was not a believer.
Indeed the point is stated by both writers explicitly. St Luke says (24: 1-11) that "on the first day of the week" Mary Magdalene and some other women found the tomb of Jesus empty, but that when they "told this to the Apostles" the latter "did not believe them" — the report "seemed to them an idle talc".
Later in the day, however, Jesus in person visited these unbelievers, invited them to gaze at him and touch him and watch him eat. They then began to believe (24: 36-43). And St John tells us, of course, that Thomas was not present on this occasion, and that his change from unbelief to belief was brought about a week later by another appearance and by physical contact with Jesus's body (20: 24-9).
And of course he also tells us that Mary Magdalene had mistaken the Risen One for a gardener, and only recognised him — and so began to believe that he had risen — when he spoke to her (20: 11-18).
These records do not support the idea that in order to see the Risen Christ it was necessary first to believe that he had risen.
(Fr) Kenelm Foster, OP Blackfriars, Cambridge.