Eighth to the Sixteenth Century - Rashid Islamic Center

240 • The Making of Islamic ScienceIt is (also) not possible for future time to have infinity inactuality: for if it is impossible for (the duration from) past time toa definite time to have infinity, as we have said previously; andtimes are consecutive, one time after another time, then whenever atime is added to a finite, definite time, the sum of the definite timeand its addition is definite. If, however, the sum was not definite,then something quantitatively definite would have been added tosomething (else) quantitatively definite, with something quantitativelyinfinite assembled by them.Time is a continuous quantity, i.e., it has a division common toits past and future. Its common division is the present, which is thelast limit of past time and the first limit of future time. Every definitetime has two limits: a first limit and last limit. If two definite timesare continuous through one limit common to them both, then theremaining limit of each one of them is definite and knowable. It has,however, been said that the sum of the two times will be indefinite; itwill then be both not limited by any termini and limited by termini,and this is an impossible contradiction. It is thus impossible, if adefinite time is added to a definite time, for the sum to be indefinite;and whenever a definite time is added to a definite time, all of it isdefinitely limited, to its last (segment). It is, therefore, impossible forfuture time to have infinity in actuality.—2—Ibn Sina–al-Biruni Correspondence, al-As‘ilah wa‘l-Ajwibah, Translated by Rafik Berjak and MuzaffarIqbal, Islam & Science, Vol. 1, Nos. 1 and 2, 2003, pp.91–98 and 253–60Writing from Khwarizm, the modern Khiva and ancient Chorasmia,Abu Rayyhan Muhammad b. Ahmad al-Biruni (973–1050) posedeighteen ques tions to Abu Ali al-Hasayn b. ‘Abd Allah ibn Sina(980–1037). Ten ques tions were related to various concepts and ideasin Aristotle’s De Caelo. Ibn Sina responded, answering each questionone by one in his character istic manner. Not satisfied by some ofthe answers, al-Biruni wrote back, commenting on the first eight