The Presumption of Continuity (Istishāb) in Respect of Something Whose Date of Occurrence is Either Known or Known

One of the important issues debated and discussed in legal studies including law, jurisprudence and its principles is the presumption of continuity in the supposition of 'a doubt in delay' (shak fi al-ta'akhur). It is evident from the sources that this doubt is not free of three scenarios. Either the date is known or it is unknown or there is one thing whose date is known and another thing whose date is not known. If the date is known, the scholars are unanimous that the presumption of continuity will not apply. If the date is unknown, two views have been recorded: Some scholars are of the view that since there did not exist a previous state of certainty, the presumption of continuity will not apply to it, while some others maintain that there is a previous state of certainty but since there was no link between doubt and certainty, therefore the presumption of continuity had not been applied.
In the event that one of them was known and another was unknown, many ideas and opinions have been presented in Usul al-Fiqh three of which have existed for a long time: Where the date of a given object is unknown Istishāb holds good and will apply to it and where the date is known, Istishāb will not apply to it.