The Evidence: Methods
Jeffrey Spier thought he had uncovered the solution to the problem of the Getty kouros when, in 1990, he discovered another fragmentary statue which seemed to exhibit the same features as the one in the Getty. Spier hypothesized that the two statues were created by the same hand, and used this as evidence of the Getty kouros as a forgery. To Spier, the discovery of a second forgery by the same hand is the best way to prove another piece fake. The Getty purchased this forged fragmentary kouros in order to test it against their own piece. Yet Spier's hypothesis proved incorrect, as extensive analysis revealed that the two pieces were not by the same sculptor due to the modern tool marks on the fragmentary kouros that the Getty kouros is lacking.
In fact, some scholars use tool markings as another piece of evidence for the Getty kouros's authenticity. The carving methods are consistent with other archaic works, in which sculptors removed stone by carving with a chisel-like tool at a high angle against the stone. Unlike with the forged fragmentary kouros, the sculptor did not attempt to hide any of the tool marks on the Getty kouros. The sculptor of the Getty kouros also used the same tool for all details much like an archaic sculptor, whereas modern sculptors are more likely to change tools depending on the area they are working on.
Proponents of the Getty kouros's authenticity have more evidence in their favor. They point specifically to the feet of the kouros, which exhibit a unique detail of archaic kouroi. The axes of the feet do not line up with the bodies of kouroi, making them appear to turn to the right. This detail is also present in the Getty kouros. To those who believe the Getty kouros to be authentic, this detail is proof simply because it had not been discovered by the art historical world when the statue surfaced in 1983. Yet to suggest that it is impossible that a forger could notice a detail art historians had not yet discovered is not necessarily true. Art historians are careful observers of objects, but no one is a more careful observer than the copyist. It would not be out of the question for a forger copying directly from an established ancient source to manage to successfully recreate this detail.
 Spier "Blinded with science," 631.
 Peter Rockwell, "Archaic Carving Technique and the Getty Kouros," In The Getty Kouros Colloquium Athens 25-27 May, 1992 (Athens: Kapon Editions-Greece, 1993), 55.
 Lapatin, "Proof?: The Case of the Getty Kouros," 47.