Tasalsul is the dependence of a thing’s existence on the fulfillment of an infinite number of conditions. Typically, it is used to refer to the belief that the present is preceded by an infinite number of past events. Tasalsul is impossible because an infinity is endless by definition, and so an infinite number of condtions cannot be fulfilled.
In proving the impossibility of the Tasalsul of time, we say: the past is the series of events which leads up to and concludes with the present. To claim that the past consists of an infinite number of events, is to claim that an infinite number of events was concluded. This is impossible because “infinite” implies endlessness, while “concluded” implies coming to an end. Thus, to say that an infinity concluded, is to say that an endlessness came to an end. This is contradictory, and is therefore impossible.
For example: it is impossible to finish counting all the negative numbers and finally reach zero. This is because there are an infinite number of negative number of negative numbers, so one cannot “finish” counting them all.