What is the ruling for a prisoner or isolated person who is uncertain of the month but strives to determine Ramadan?
General Chapter
Al-Mughni
Book of Fasting
Primary text
If someone, such as a prisoner or one in a remote area unable to ascertain months by report, is uncertain of the months and strives to determine Ramadan, if he concludes with a strong presumption that it is Ramadan, he fasts, as he has fulfilled his obligation by Ijtihad (independent reasoning). If the situation remains unclear, his fast is valid. If it becomes clear that his fast coincided with Ramadan or a month after, it suffices according to the majority. If it becomes clear that he fasted before Ramadan, it does not suffice according to the majority.
Supporting text
Al-Hasan ibn Salih is reported to have stated that if it becomes clear the fast coincided with the month following Ramadan or was a doubt, it is not sufficient in both cases, because he fasted based on doubt, analogous to fasting the Day of Doubt when it turned out to be Ramadan. This view is rejected because he fulfilled his duty through Ijtihad in a valid context. Some Shafi'i scholars allow sufficiency if it coincides with the next month, similar to being mistaken about the Day of Arafah.