Conjecture is a critical reconstruction of the original reading of a clearly corrupt, contaminated, nonsensical or illegible textual fragment. Conjecture is one of the techniques of textual criticism

Textual criticism

Textual criticism is a branch of literary criticism that is concerned with the identification and removal of transcription errors in the texts of manuscripts...

 used by philologists while commenting on or preparing editions of manuscript

Manuscript

A manuscript or handwrite is written information that has been manually created by someone or some people, such as a hand-written letter, as opposed to being printed or reproduced some other way...

s (e.g. biblical

Biblical manuscript

A biblical manuscript is any handwritten copy of a portion of the text of the Bible. The word Bible comes from the Greek biblia ; manuscript comes from Latin manu and scriptum...

 or other ancient texts usually transmitted in medieval copies). Conjecture is far from being just an educated guess and it takes an experienced expert with a broad knowledge of the author of the text, period, language and style of the time. Conjecture requires a close study of the text in its cultural and historical context and must be preceded with a thorough analysis of all extant

Extant literature

Extant literature refers to texts that have survived from the past to the present time. Extant literature can be divided into extant original manuscripts, copies of original manuscripts, quotations and paraphrases of passages of non-extant texts contained in other works, translations of non-extant...

 versions and readings of the given fragment. The knowledge of writing styles used by the scribe

Scribe

A scribe is a person who writes books or documents by hand as a profession and helps the city keep track of its records. The profession, previously found in all literate cultures in some form, lost most of its importance and status with the advent of printing...

s throughout the transmission stages is also essential. Conjectural emendation should be seen as a solution of the last resort and must be clearly indicated in the critical apparatus

Critical apparatus

The critical apparatus is the critical and primary source material that accompanies an edition of a text. A critical apparatus is often a by-product of textual criticism....

or in the text itself.