Does is it stress anyone else out the sheer amount of books there are, and the fact that many may be lost in the distant future?
This basic idea--down to the use of a cup as a metaphor--is at the heart of Stoicism also. From the Enchiridion of Epictetus (§3):
With regard to whatever objects give you delight, are useful, or are deeply loved, remember to tell yourself of what general nature they are, beginning from the most insignificant things. If, for example, you are fond of a specific ceramic cup, remind yourself that it is only ceramic cups in general of which you are fond. Then, if it breaks, you will not be disturbed. If you kiss your child, or your wife, say that you only kiss things which are human, and thus you will not be disturbed if either of them dies.
In essence: if you really love the cup, love it and experience it for what it is, which is clay. Breaking is simply what hardened and fired clay does, it is one of the activities of clay, in addition to forming cups and holding stuff for you. Only if you ignore part of it will you be surprised and upset when it simply does one of the things that clay does. If you're upset, you were simply "wrong about the cup." You didn't really love the cup in the most... let's say, "precise" way; you loved some idea of what the cup was that did not entirely match reality. Which was fine for a while, but now it's on the floor in pieces and you're paying for it.
By the way, this is one of the more difficult and controversial passages of Epictetus, as it seems to get at the thing that people have always misunderstood about the Stoics (and, because of translation issues, is even easier to misunderstand in English). So: go ahead and apply to wives and children what you learned from cups, and you won't be "disturbed" when they sicken or die (which is what flesh and blood does, just like cups break). Cool idea, bro! That seems somewhere between shocking and just plain unrealistic (or both). Bertrand Russell famously kind of pooh-poohed Stoicism, I think largely because he read that attitude as part of a kind of British "stiff upper lip" emotionally suppressive habit that he rightly saw as the cause of so much needless suffering. But that, I think, is the wrong reading of it.
So, "disturbance" seems kinda neutral to us as a word, and so when somebody tells you that you ought not to get disturbed when something awful happens to your family, that sounds a bit naive. But the original terms used to describe these kinds of disturbances throughout Stoic writing are generally more extreme. The main one is "πάθεια," that is, patheia, which comes down to us more directly in words like "pathological" and "pathology." What Epictetus is saying is not that you won't be bothered when your wife sickens or dies, but that you are able to free yourself from being pathologically bothered. And what might constitute pathology? Well, that may depend on the situation, and certainly one might be allowed much more powerful emotion for the wife than for the cup. Suffice it to say that you'll still be sad or anxious--perhaps very sad or anxious--and mourn if she dies. But for a Stoic, that emotion will not interfere with your duties to her, to your family, to your community, which are able to be carried out even with the presence of that emotion. Thus the Stoic goal of having apatheia (apathy!), although it sounds to us like "not caring about anything" because of our connotation of the word, it actually refers to "caring about the things you ought to care about, and possessing beliefs which do not create unhelpful emotions that carry you away from those things." The original emotion you can't help (which is fine, by the way, because emotions themselves aren't bad and are often useful). You will catch them like you catch yawns, says Seneca the Younger (De Ira, II.4.2):
We cannot escape the first shock of the mind by reason, just as we cannot escape those things we mentioned which befall the body either, so as to avoid another's yawn infecting us, or avoid our eyes blinking when fingers are suddenly poked toward us. Reason cannot control these things, though perhaps familiarity and constant attention may weaken them. The second movement, which is born of judgement, is removed by judgment.
So, a decade or so ago, when an aunt I was very close to stopped her last try at chemo and I didn't talk to her for a month because I was a scared adolescent too upset to speak to her with the idea of her dying in my mind, that's not sadness or anxiety, that's patheia--sadness or anxiety that prevented me from doing my duty to her (I got over it in time, thankfully). That was a level of sadness or anxiety which served to keep me from her, rather than brought us together as we are supposed to be, since as human beings, Marcus Aurelius tells us in the Meditations (II.1), we are
made for co-operation, like feet, like hands, like eyelids, like the rows of the upper and lower teeth. To act against one another then is contrary to nature; and it is acting against one another to be vexed and to turn away.
And that's really much of what Stoicism is about. Not to be logical and stomp down your feelings, but to believe things about the things around you that are accurate and real and correct, so you are able to feel feelings while still doing your duties, and still being connected to the rest of the humans with whom you make up a single body. Getting much of the way there is not quick or easy, but it's also not something you have to sit meditating in a cave for decades to do--it is likely not to be achieved perfectly, but it is achievable in recognizable proportion with some effort. For the study and practice I have dedicated to it, my life is, I would like to think, both a happier and a more virtuous life than it would have been otherwise.
TL;DR: Wanted to share a similar cup metaphor and ended up needing to explain a big chunk of Stoicism, which might be substantially off-topic in this /r/books thread--sorry
Source: clinical psychology PhD student who treats mostly anxiety/PTSD and is interested in the integration of cognitive-behavioral therapy and the Stoic philosophy which originally underlies it