The first view is that his fast does not suffice unless he intends it specifically for Ramadan. If he fasts with a general or conditional intention, or intends a voluntary fast or a fast in fulfilment of a vow, it does not suffice. This is the well-known position in al-Shāfi‘ī’s school and one of the reports from Ahmad.
The second view is that it suffices in all these cases, as in the school of Abū Hanīfah.
The third view is that it suffices with a general intention, but not with an intention specifically designating a fast other than Ramadan. This is the third report from Ahmad, and the view chosen by al-Khiraqī and Abū al-Barakāt.
The correct analysis of this issue is that intention follows knowledge. If a person knows that tomorrow is part of Ramadan, he must specifically intend to fast for Ramadan in this case. If he intends a voluntary fast or merely fasting in general, it does not suffice, because Allah has commanded him to intend to fulfil the obligation incumbent upon him: fasting the month of Ramadan, which he knows to be obligatory. If he does not fulfil that obligation, he has not discharged his liability.
If, however, he does not know that tomorrow is part of Ramadan, he is not required to specify his intention in this way. Whoever requires him to do so despite his lack of knowledge has imposed two mutually incompatible requirements. Thus, if fasting that day is deemed permissible, and he fasts in these circumstances with a general or conditional intention, his fast suffices. But if he intended to fast that day voluntarily, and it then became clear that it had been