הבה נבנה לנו עיר וגו' - לפי הפשט מה חטאו דור הפלגה? אם מפני שאמרו וראשו בשמים, הא כת' ערים גדולות ובצורות בשמים? אלא לפי שצום הק' פרו ורבו ומלאו את הארץ, והם בחרו להם מקום לשבת שם ואמרו פן נפוץ, לפי' הפיצם משם בגזרתו:
The first 9 verses of chapter 11, despite their relative brevity, are packed with interpretive possibility. What did the generation of the dispersion (דור הפלגה) do wrong in this story? Was it the fact that they all spoke the same language and thus revealed totalitarian like tendencies to crush diversity? Was it their turn away from a nomadic lifestyle to the technology of building and civilization? Perhaps it was the choice of an urban life over a rural one, thus disconnecting themselves from more directly confronting God through raw exposure to nature? Or was it, as is often assumed, the building of a tower that was to be so high it would reach to heaven, an act which revealed a desire to rebel against or at least share power with God?
Rashbam, noting that elsewhere in Tanakh, large, impressive cities that are described as being בשמים are allowed to stand, argues that the height and prominence of the architecture cannot be the heart of the problem here. Instead, he focuses on פן נפוץ, the articulated motive of builders to avoid being dispersed. This, argues Rashbam, was a direct contravention of the order given to Noah and his line to fill the earth and to spread out. Interestingly, the “local” peshat here indeed seems to be focused on the tower and on God’s concern regarding excessive human power. But Rashbam reveals a synthetic approach to peshat here that attempts to make sense of this passage in light of others.
[For another commentary that builds on this approach—and for the notion that the tower was intended to function as a kind of panopticon designed to control human behavior—see העמק דבר, R. Naftali Tzi Yehudah Berlin’s commentary here.]