In Chapter Seven, the fundamental principles used to define the minimum measures that determine liability for carrying out various substances were established. One who carries out any item “fit to store” into a prohibited domain on Shabbat is liable to bring a sin-offering for that action. An item considered “fit to store” is one that people generally store and one whose measure is large enough to make it worthwhile to store for future use. Any measure less than that is considered insignificant, and there is no Torah prohibition against carrying it out. This principle determines the minimum measures that determine liability for carrying out on Shabbat; however, it does not specify the measures with regard to each and every substance.
In the eighth chapter, which begins on today’s daf the Sages specified that which is considered a significant measure with regard to a wide range of substances. The challenge here is not merely to establish minimum measures for the various substances, but it extends to more fundamental issues. For example, with regard to substances that have several uses, and a different measure is typically utilized for each of its uses, the question arises whether one universal measure determines liability for carrying out this substance, or whether the measure that determines liability varies in accordance with the purpose for which the substance is being carried out.
Moreover, even if one universal measure determines liability for carrying out a particular substance in all cases, is that measure determined by the substance’s most common and significant use or by the largest or smallest of the measures?
In addition, the measure that determines liability for substances that have no independent utility but serve a purpose when combined with other substances is discussed. Is the measure of that substance alone deemed significant because that is the measure typically mixed with another substance, or would one be liable only for carrying out the entire mixture?
The explication of these general issues and their details is the focus of this chapter.