Epictetus used to say that when you kiss your child you should say to yourself: 'Tomorrow you may be dead.' But these are ominous words! 'No,' he replies, 'nothing is ominous which points to a natural process. Otherwise it would be ominous to speak of the corn being reaped.'
Grapes unripe, ripened, raisined: all changes, not into nonexistence, but into not-yet existence.
'No thief can steal your will' - so Epictetus.
Another saying of his. 'We must discover an art of assent, and in the whole field of our impulses take care to ensure that each impulse is conditional, has a social purpose, and is proportionate to the value of its goal. We must keep absolutely clear of personal motivation, and at the same time show no disinclination to anything outside our immediate control.'
Again. 'So this is not a contest for a trivial prize: at issue is madness or sanity.'
Socrates used to question thus. 'What do you want to have? The souls of rational or irrational beings?' 'Rational.' 'What sort of rational beings? The pure or the lower?' 'The pure.' 'Why then don't you aim for that?' 'Because we have it.' 'Why then your fighting and disagreements?'
As morbid as it may seem, we must all prepare for any event, including the death of our children. This is called premeditatio malorum. And even that term is a misnomer. Preparing for "bad" things accomplishes two things. 1) when a "bad" thing happens, we won't be surprised. 2) secondly, begin to realize these aren't "bad" things, rather they are just natural events, in many cases. In this specific case, the "bad" thing is your child dying pre-maturely. We think this is bad because we expect something to happen that is out of our control. When in reality, children and humans die all the time. Corn ripens and is picked and eaten. Is this bad? No, it is natural. Humans die - it is natural.
I often tell my wife, when speaking about one or all of our children (when they do something no-so-smart), "this is not the final version of ..." The idea is that we are always changing and learning. A grape may be a grape today, but tomorrow it will be a raisin. Nothing good or bad about a grape or a raisin. They are composed of the same material, but just at a different stage of development. So too with humans.
"Sticks and stones may break my bones, but words will never hurt me." The only one who can harm my will is me. Thieves break into my home, but they can never break into my mind.
The art of assent (the discipline of assent in modern Stoic terms) - is the ability to control our impulses. Not only should we work to control our impulses, but we should ensure our impulses have a social purpose. And always ... always ... keep in mind what is in your control and what is out of your control.
What is at stake with philosophy? You will either be mad (in some sort or fashion) of you will be mad (in some sort or fashion). I'd prefer to be sane.
The aim, according to Socrates, is to be rational, pure and content.
(see also Citadel p. 66, 68, 70, 188, 206-207, 215)