One approach to understanding Yaakov's question is that Yaakov did not recognize Efrayim and Menashe since he had poor vision, as recorded in 48:10. Ibn Ezra and Rashbam (on 48:8) suggest that due to his poor vision he saw their figures but not clearly enough to identify them. Yet, later on when Yaakov placed his hands on their heads he was able to identify them, 48:19. Radak (on 48:8) suggests that Yaakov could not identify Efrayim and Menashe since they were initially standing far away from him (nearsightedness?), while later they were close to him and then he could recognize them. However, this approach is difficult since the Torah tells us that Yaakov had poor vision after Yaakov asked his question, “who are they?” which implies that Yaakov’s lack of recognition of his grandchildren was not due to his poor eyesight.
A second approach is that Yaakov knew who they were but the question was part of a formal process of establishing their identity. Yehuda Keel (2003, on 48:8) quotes R. Samuel ben Hophni Gaon (d. 1013) that maybe the question was an opening to a conversation or a confirmation, though it is not clear what was the need for an opening to a conversation or a confirmation.
Sarna (1989, p. 326) follows this approach and the idea that Yaakov was adopting Efrayim and Menashe. He suggests that the question "who are they" was “the second stage of the legal adoptive process, namely the establishment of the true identity of the candidates for adoption by formal interrogation of the natural father.” Sarna refers to this act as the second stage since Yaakov had already began the “adoption” process (48:5,6) before he asked the question “who are they?”
Yet, one would have thought that if the question was to establish the identity of the people being adopted, then this question would have been asked at the beginning of the process and not in the second stage. However, maybe one can argue that the official adoption did not begin until 48:10. Another problem with Sarna’s approach is that Yaakov began the “adoption” process without knowing that Efrayim and Menashe were present in the room since he did not call for Efrayim and Menashe to come to him. It appears that Yaakov did not think they had to be present when they were being adopted. This suggests that there was no need to establish their identity through this question, but rather Yaakov was able to adopt them without them being present and it was sufficient for Yaakov to refer to them as Yosef’s sons, as he did in 48:5.
Following the Radak, it appears that Yaakov could only see at very short distances, and then Yaakov did not immediately see Efrayim and Menashe, even as vague forms, when they entered his room because they were standing at a distance beyond his field of vision and only Yosef had approached Yaakov when all three entered the room.
Afterwards, when they heard that Yaakov was treating them as his natural sons Reuven and Shimon and that they would be included in the inheritance with their uncles, 48:5,6, they moved closer to Yaakov. At this point, he was not able to identify them not because of his poor vision, but because when they moved closer to him, most likely they bowed down to him to show their appreciation for equating them to their uncles, and hence Yaakov only saw the back of their heads. Following Dresner, Yaakov did not see their faces when they bowed since he was not concentrating on what was going on around him because at that moment he was thinking about Rahel. Furthermore, he had no reason to think that they were in the room since he had not been told that they had come with Yosef and he had not called for them. Yaakov saw two people bowing down to him, but he could not identify his grandchildren by just seeing the back of their heads, and hence he asked Yosef who are these people?
Bibliography:
Dresner, Samuel, 1994, Rachel, Minneapolis: Fortress Press.
Keel, Yehuda, 1997, 2000 and 2003, Commentary on Bereshit: Da'at Mikra, Three volumes, Jerusalem: Mossad Harav Kook.
Sarna, Nahum (1923-2005), 1989, The JPS Torah Commentary: Genesis, Philadelphia: The Jewish Publication Society.
Bibliography:
Dresner, Samuel, 1994, Rachel, Minneapolis: Fortress Press.
Keel, Yehuda, 1997, 2000 and 2003, Commentary on Bereshit: Da'at Mikra, Three volumes, Jerusalem: Mossad Harav Kook.
Sarna, Nahum (1923-2005), 1989, The JPS Torah Commentary: Genesis, Philadelphia: The Jewish Publication Society.