فالوجوب بالذات كما في الواجب الوجود...

و الإمكان بالذات, كما في الماهيات الإمكانية, فإنها في ذاتها لا تقتضي ضرورة الوجود و لا ضرورة العدم; و الإمكان بالقياس إلى الغير, كما في الواجبين بالذات المفروضين, ففرض وجود أحدهما لا يأبى وجود الآخر و لا عدمه, إذ ليس بينهما علية و معلولية و لا هما معلولا علة ثالثة. و أما الإمكان بالغير فمستحيل, لأنا إذا فرضنا ممكنا بالغير, فهو في ذاته إما واجب بالذات, أو ممتنع بالذات, أو ممكن بالذات, إذ المواد منحصرة في الثلاث, و الأولان يوجبان الانقلاب, و الثالث يوجب كون اعتبار الإمكان بالغير لغوا. 4.2.

THE SUB-DIVISIONS OF EACH OF THE MODES Each of the three modes is divisible into three kinds: (i) essential (bi al-dzât), i.e., that which is such (i.e. necessary, contingent or impossible) by-itself, (ii) accidental (bi al-ghayr), i.e., that which is such by something else, and (iii) relative (bi al-qiyâs ila al-ghayr), i.e., that which is such in relation to something else.

An exception here is the ‘contingent,’ for which there is no such subdivision as ‘contingent by something else.’ The exalted Necessary Being, whose existence is necessary by itself, without standing in need of anything else, represents essential necessity. By ‘accidentally contingent’ is meant the contingent whose existence becomes necessary upon the existence of its cause.

Relative necessity applies to the existence of each of two correlatives (mutadhâ‘afayn), whose existence is necessary in relation to that of the other correlative, like the higher one and the lower one, the existence of each of which is necessary in relation to that of the other, apart from the necessity arising from their cause.

Examples of the essentially impossible are such essential impossibilities as God’s partner (sharîk al-Bârî) and the coming together of two contradictories (ijtimâ’ al-naqidhayn).