This is german philosopher Gotthold Ephraim Lessing. He was a prominent philosopher of the 18th century, as well as art critic and dramatist. Kierkeegard spent much time in his Concluding Unscientific Postscript dealing with Lessing's thoughts on epistemological leaps to faith.
Judging from his picture, Lessing also had an almost perfectly symmetrical triangular head, which unfortunately was never discussed in Kierkegaard's work.
I'm about halfway through with ...Postscript, and finding great freedom in Kierkegaard's subjective Christianity. I'm also wondering if there's any sort of hard connection from S.K. to reformed epistemology and other postfoundational ideas of rationality.
"Christianity does not lend itself to objective observation, precisely because it proposes to intensify subjectivity to the utmost; and when the subject has thus put himself in the right attitude, he cannot attach his eternal happiness to speculative philosophy." -S.K.
Belief in God is properly basic.
Such a joy to read and know!!