Yevamot 68 & 69

If I had to pick a theme that emerges from our study of Yevamot 68 & 69, it would be ‘transitions’, and in particular, how reaching a certain physical age is indicative of having reached a certain transitional stage, and similarly, how particular life transitions, such as marriage, are reflective of starting a new stage of life.
For example, we are taught in Yevamot 68a that the daughter of a Kohen, while living in her parents’ home, eats from Terumah due to her membership of that household. However, we are then taught that she is not permitted to eat Terumah once she marries and leaves home (presuming that she doesn’t marry a Kohen). This is because she has transitioned from being a member of one household to becoming a member of another.
Similarly, within the Gemara’s continuing discussion about the consumption of Terumah, reference is made in Yevamot 69b to the fact that once an egg is fertilized, a fetus is considered מיא בעלמא – ‘just’ water – for its first 40 days.
Significantly, and this is a point that numerous commentaries explain, this statement is not to be understood as providing us with a comprehensive legal, spiritual or philosophical evaluation of the status of a fetus before this point. Instead, it is stated within a discussion about the laws of Terumah in order to teach us that 40 days is the age which indicates reaching a certain transitional stage of a pregnancy.
Yes, it is true that certain ages are suggestive of certain stages, and it is also true that certain transitions are indicative of particular shifts in identity and identification. Still, just as someone who reaches their bat/bar mitzvah is called an adult, but – if we were honest about what this really means – it actually just indicates that they have reached adulthood for certain mitzvah responsibilities and for particular aspects of communal participation, so too, when we speak of reaching a certain age and stage, we need to be clear what those distinctions and transitions are for, and what they suggest, as well as what they don’t necessary convey or tell us in terms of the legal, spiritual or philosophical status of a being.