I don't grasp this Reddit comment.
An example of (3) might be this (from a 15th-century will):
I now the seid John Smyth, for diu[er]se causez and consyderacyonys shevyd vnto me, will ordeyne and declare ...
Here, "consideration" means "something to be considered, a reason". The semantic sense has shifted from the act of considering to the thing considered. A parallel might be the word "obligation", where the shift is from the act of obliging, to the thing one is obliged to do.
These semantic shifts are too apart, far-reaching, far-fetched for me to grasp! To the common Anglophone, "the act of considering" plainly differs from "the thing considered". For instance, rational humans perform "the act of considering", while "the thing considered" is an inanimate valuable object like money.
How can I interpret these semantic shifts so they feel natural, intutitive common sense? How can these semantic shifts be bridged?