The quality of being based on conjecture; the nature or state of being conjectural rather than certain.
From conjectural plus -ity suffix, which creates abstract nouns from adjectives. Both -ity and -al are Romance-language influenced suffixes that English adopted during the Middle English period.
The conjecturality of ancient history is why archaeologists get so excited about new discoveries—each artifact reduces the territory of educated guessing by a tiny but real amount.
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