Study Guide Pesachim 12 A week of learning is dedicated by my parents, Robert and Paula Cohen in memory of my grandfather, Joseph Cohen, Yosef ben Moshe HaKohen z"l. Today's daf is sponsored by Lesley Glassberg Nadel in memory of her father Bernie Glassberg - Berel ben Herschel haLevi z"l on his yahrzeit. And by Pamela Kaplan commemorating the 16th Yahrzeit of her father, David Kaplan, David Abba ben Aharon z"l. And by Cheryl Goldschmidt in memory of her father’s 7th yahrtzeit Eddie Tager, Yitchak Eizak Simcha ben Yechiel Mechel z"l. And by the Hasenberg Family in honor of Steven Aftergood’s 64th birthday. "May HaKadosh Baruchu bless Steven to live to be 120 and every day be filled with joy and Torah. With all our gratitude for him in our lives." And for a refuah shleima for Rav Dov Shabtai ben Yehoshua Lev.  To what extent do we assume people make mistakes in determining what day or what time of day it is? Do what extent does human error factor into the rabbis decisions when determining halacha? This issue is relevant to the time the rabbis determined for forbidding chametz on Erev Pesach and also for determining whether or not witnesses are disqualified if the time is their testimony doesn't line up. The gemara brings three explanations to explain the opinion of Rabbi Meir and Rabbi Yehuda in Sanhedrin 40 and then tries to reconcile that with their opinions regarding chametz in our mishna. Why are these cases treated differently? When did people eat meal in the time of the Talmud?