Men trifle with the most precious thing in the world; but they are blind to it because it is an incorporeal thing, because it does not come beneath the sight of the eyes, and for this reason it is counted a very cheap thing
the idea that value comes from only those tangible things. This is similar to Epicurius idea of sensation?
There is nothing the busy man is less busied with than living: there is nothing that is harder to learn
I like this acknowledgement of the ultimate art being life itself rather than some specific discipline done within it. The acknowledgement of how difficult that is, and how you don't actually learn it till it's just about over, is correct.
But these matters can be shown better by deeds than by promises. Nevertheless, since the joyful reality is still far distant, my desire for that time most earnestly prayed for has led me to forestall some of its delight by the pleasure of words.
Only under certain criteria is it ok to merely think of joy rather than pursue it.?
What foolish forgetfulness of mortality to postpone wholesome plans to the fiftieth and sixtieth year, and to intend to begin life at a point to which few have attained!
This reminds me of the common idea of college students to make a lot of money in the ten years after college and then do what they're passionate about. I agree with this point on a larger scale, that tossing away years as a number is foolish.
The part of life we really live is small
Seneca frames this as a bad thing, but once again, it is important to remember that the mind cannot handle "really living" at all times. Additionally, it is part of really living to be unaware at times. To be focussed, to be doing rather than observing.
the life we receive is not short, but we make it so, nor do we have any lack of it, but are wasteful of it.
Although this is a wise statement, and encourages the generally well thought of principal of appreciation, it is important to realize how this can be overdone. If we put so much pressure on every aspect of our life to be packed with meaning, it will lose that very meaning.