In the late 90s, psychologists began using the term
inattentional blindness. This describes the experience of being so concentrated on one thing that a person altogether misses something else — something that would otherwise be glaringly obvious. This video is a great example of it:
This seems to be exactly what happens in the Gospel story today! Two disciples, afraid for their lives, are fleeing Jerusalem and doing their hardest not to be seen or noticed by anyone. Suddenly Jesus appears with them, walking along. He tries all day to engage them in conversation but they never recognize him.
What could they have been so focused on that they missed the Son of God walking right beside them? These two disciples had so succumbed to sadness, fear, and despair that even when the Lord himself was with them they didn't know it. It's a great reminder to us, in these strange days, that no matter how we are feeling, the real presence of Jesus Christ is walking right alongside us.