Hello Rabbi! Three questions. First, how come the Tosefta doesn’t mention Rebbi Yehoshuas opinion of three hours being the deadline? Second, is there any shitah that says that, as soon as you wake up, even if after the third hour, and you say Shema, you are Yotzei? This is definitely relevant for teenagers, who naturally have later sleep cycles. Lastly, since nowadays many people do wake up a lot later, especially when people have break from work or school, shouldn’t the latest time for Shema be later? And the same for night time Shema, especially in the winter, no one goes to sleep at 5 or 6pm, maybe at the earliest 9 or 10pm. Shouldn’t the earliest time for Shema at night be later then? Thank you so much!

Shalom, Thank you for your questions. Great to see that you are learning Mesechet Brachot with such an interest. May you be blessed with every success in your learning! Now to your questions - 1) I am not familiar with the reasoning of the Tosefta with relation to R’ Yehoshua’s opinion (sorry). 2) and 3) are based on the idea – that the “time of arising” should change (for individuals or for all of society) because of changes in our normative practices. While this idea has some basis in relation to certain halachot – here it does not apply (and there are no opinions that hold that way), I heard from HaRav Osher Wiess Shiltah, that only Chazal had the ability to give halachic definitions to Torah commands. That is to define what is “when you arise” and “when you lie down”. And once they defined them, they are binding throughout all periods. This is true with many definitions of Torah commands. For example, what defines the specialness of Chol HaMoed, or the laws of mourning. Once Chazal gave form to the Torah command, that definition is unchanging. Blessings