Chapter 4, ‘The Efficacy of Empirical Vision’, argues that physical sight can and should lead to belief in John. Scholars often cite John 2:23; 4:48; and 20:29 as evidence for John’s own critique of physical seeing as a means of coming to belief. The chapter argues that close reading of John 2:23 and 4:48 reveals human hearts to be the true cause of unbelief and shows that physical sight is the catalyst for all unbelief and all belief. Neither does John 20:29 condemn sight as a means of acquiring belief. Rather, it suggests that mediated seeing – via the text of the Gospel – can be as efficacious for belief as an actual encounter with Jesus. The chapter concludes that sight is complex, but that no critique of the positive relationship between sight and belief exists in John.