From Soren Kierkegaard: A Biography by Joakim Garff:
When he was born, Søren Aabye had three sisters aged sixteen, thirteen, and eleven, and three brothers aged seven, five, and four. Three of each sex was nice symmetry, and their double names added a peaceful sort of harmony. Søren Aabye Kierkegaard broke the equilibrium: As the conclusion to the flock of seven children he seems to have been as unplanned as the manner in which it all began. Nor was he an easy boy to deal with. Indeed, according to his second and third cousins he was a rather mischievous little fellow whose company was better avoided. One of these cousins thus described him as “a frightfully spoiled and naughty boy who always hung on his mother’s apron strings,” while another noted laconically that “as usual, Soren sat in a corner and sulked.” At home he bore the nickname “the fork,” because that was the utensil he had named when he had been asked what he would most like to be: “A fork,” the freckled little boy had answered. “Why?” “Well, then I could ‘spear’ anything I wanted on the dinner table.” “But what if we come after you?” “Then I’ll spear you.” And the name “the fork” stuck to him because of “his precocious tendency to make satirical remarks” (pp. 8-9).
From Kierkegaard’s Metaphors by Jamie Lorentzen:
The pet name/metaphor for Kierkegaard the polemicist and rhetorician extends to Kierkegaard the literary stylist and metaphorist. His childhood name in the family home speaks first to one form of metaphoric writing, namely, satire. In specific reference to his nickname, Kierkegaard’s niece, Henriette Lund, considers her uncle as having a “precocious tendency to make satirical remarks.” But the metaphor for Kierkegaard the author need not end there. “The Fork” befits his metaphoric style: it has more than one prong to “spear anything” one wanted, just as a good metaphor has more than one “prong” (at least one tenor and one vehicle) in which to “spear” any meaning more fully than a univocally communicative form. Metaphor offers Kierkegaard the poetically forked tool by which to speak with greater effect ideas in any sphere of existence. Further, the “forked tongue” implication of the nickname exposes Kierkegaard as one who entertains, if not traffics in, acts of deception (p. 41).