originally posted January 2, 2016
See Rashi on Vo'eira 6:18.
Basing himself on the phrase, "Hayyei Qehat," Rashi asserts that the text here can't be taken literally. A logical reading of other passages shows that it would have been difficult, if not impossible, for Bnei Yisrael to have spent 400/430 years in Egypt. Then the issue remains, what to do with the 400/430 years!?
It seems to me that Rashi could have gone the other way. That is, why not say the Yichus was not literal instead? Why not say that generations were skipped and so that literally was the number of years!
The response to that is that Hazal have deemed that period as 210 years. It has been adopted AFAIK by Seder Olam
This same issue is in a previous NishmaBlog poll re: may we set aside a literal reading of text when Hazal themselves have not chosen to do so? (For the results of that poll, see http://nishmablog.blogspot.ca/2011/01/results-of-poll-on-parshanut-how.html)