《Tetrabiblos》Book 1Claudius Ptolemy（Ashmand 英譯 1822）
There are also persons who imagine that whatever they themselves have not been able to acquire, must be utterly beyond the reach of all understanding; while others again will consider as useless any science of which (although they may have been often instructed in it) they have failed to preserve the recollection, owing to its difficulty of retention.
段落 tetra-1-ch-5public-domain (Ashmand 1822)
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