730 RENAISSANCES

no natural human sentiment of gratitude to restrain them from ruth-
lessly consigning this discarded belief to the scrap-heap, as a nuisance of
which they must resolutely rid their minds for fear that it might breed
intellectual confusion and error there if they were to dwell on it at the
prompting of their own better feelings.

When once men of science have thus condemned some previously
orthodox belief, it is idle for the historian to upbraid them for this
impiety towards their predecessors. He will meet with no success in his
endeavour to prick these hard hearts to compunction. The mathemati-
cian's and the scientist's judgement on the history of Mathematics and
Science runs on the lines of the Caliph 'Umar's legendary dispatch to
his lieutenant 'Amr b. al-*As in reply to 'Amr's request for instruc-
tions for the disposal of a Ptolemaic Library at Alexandria in which
the treasures of an Hellenic literary culture had been accumulating
for the best part of a millennium by the date of the Arab conquest
of Egypt. 'If these writings of the Greeks agree with the Book of
God, they are useless and need not be preserved; if they disagree,
they are pernicious and ought to be destroyed'1 is the minute which
'Umar is said to have made on cAmr's query. 'If these tenets held by
our predecessors agree with those held by us today, they are useless
and need not be preserved; if they disagree, they are pernicious and
ought to be destroyed* is the answer which, in fact and not in fiction,
the historian evokes from the mathematician and the scientist when
he begs them to take a pious interest in the genesis of their own current
beliefs.

If we have now sufficiently explored the difference between the his-
torian's and the mathematician's or scientist's respective interests in the
same mathematical or scientific proposition, we may pass on to an
examination of the difference between the historian's way of apprehend-
ing a thought that has been thought in other minds before his, and his
way of apprehending the manifold human experience in which every
act of thought is actually implicated in real life.

We have observed already2 that the historian, when he is thinking for
himself a thought that has also been entertained by some other person's
mind in some other time and place, is not interested in the naked thought
for its own sake; he is interested in it as a possible spring-board from
which he may perhaps find himself able to take a flying leap into psychic
communion with that other person who, in his own act of entertaining
the same thought, was certainly animated by feelings associated with his
act of thinking, and was perhaps also meditating, planning, or executing
some associated act of will for the weal or woe of his contemporaries.
This interest, which is a genuine historian's abiding ultimate interest,

* Gibbon, Edward: The History of the Decline and Fall of the Roman Empire, chap, li,
paraphrasing the thirteenth-century Jacobite Monophysite Patriarch of Antioch, Abu'l-
Faraj (alias Mar Gregor of Malatiyeh, alias Bar Hebraeus). Gibbon's paraphrase is based
on a passage on p. 114 of Edward Pocock's Latin translation (Oxford 1663, printed by
H. Hall, Printer to the University) of 'AbulpharagiusV own Arabic translation, from the
original Syriac text, of the political part of his chronicle of universal history, both
political and ecclesiastical. The title of this Arabic version is Tdrikh Mukhtasar al-Dutual
\Hist9ria Compendiosa Dynastiarttm"). The story has been cited in VI, vi. in-ia.

1 On p. 729, above.