The Conspiracy Theory
Let's take a look at the events from Yosef's perspective. At age 17, full of teenage energy, emotion and ambition, Yosef is sent by his father to check on his brothers. As soon as they see him, they immediately take off his coat and throw him into a pit. Only a short time later, a group of Midyanim (or his brothers - see last week's shiur) remove him from the pit and sell him to a caravan of Yishmaelim. Yosef concludes that his brothers are either pulling some type of 'prank' on him, or may have even sold him into slavery. Recall, however, that Yosef never heard the brothers' original plan to kill him. Most likely, Yosef concludes that as soon as his brothers come home, his father will investigate the matter (or someone will snitch), and Yaakov will make sure that Yosef is found, by tracing the sale to Egypt.
Yosef is totally unaware that the brothers had tricked their father with the blood-stained coat. He has no idea that his father presumed that he was killed by a wild animal.
The months pass, and nothing happens. Yosef begins to wonder why no one has come to look for him. Does his father no longer care about him? Why did the brothers throw him into the pit as soon as he arrived? Why did his father send him out alone on such a long journey to see his brothers who hated him? Slowly, Yosef comes to the realization that Yaakov must have received some divine decree that Yosef is rejected, and only Leah's children [and not Rachel's] had been 'chosen.' Rachel, as her premature death may have indicated, had not attained the same matriarchal status as Sarah and Rivka.
In his article, Rav Bin Nun even suggests that Yosef may have entertained the thought that this entire conspiracy to sell him may have been coordinated by his father. He raises the possibility that Yosef (after many years of pondering these events) may have concluded that his father had actually sent him knowing that the brothers would sell him. Rather than confront Yosef directly with the terrible news of his 'rejection' from the family, Yosef thinks that Yaakov may have preferred that the brothers do the 'dirty work' for him.
However, it is possible to follow a similar direction without the need to entertain this 'consipiracy' theory, which itself appears to be a bit far-fetched. One could suggest that Yosef may have supposed that when the brothers returned home, they had convinced their father that Yosef's disappearance was a Divine indication of his rejection.