Affection
Affection is the manifestation of one of the four loves of the title; it an expression of the empathy bond. Here, Lewis describes why in perhaps surprising metaphorical terms:
“For Affection is the most instinctive, in that sense the most animal, of the loves; its jealousy is proportionately fierce. It snarls and bares its teeth like a dog whose food has been snatched away.”
Friendship
Friendship also gets the metaphor treatment from Lewis and, once again, the comparison engaged in the simile may be disconcerting. Certainly, it is likely not the first metaphorical image to come to most people’s mind:
“Every real Friendship is a sort of secession, even a rebellion. It may be a rebellion of serious thinkers against accepted clap-trap or of faddists against accepted good sense; of real artists against popular ugliness or of charlatans against civilised taste; of good men against the badness of society or of bad men against its goodness.”
Erotic Love
Perhaps because Lewis was associated with Christian themes or possibly just because the work started as a series of radio lectures I 1958, when it comes to third type of love—sexual and passionate romance---throughout the essay Lewis refers to the topic through a familiar metaphorical figure:
“By Eros I mean of course that state which we call `being in love’; or, if you prefer, that kind of love which lovers are `in.’”
Eros, Part II
Lewis struggles somewhat to discuss erotic love without metaphor, but this can be forgiven because his some of his metaphors need no further explanation. It is clear enough what is meant:
“Eros, honoured without reservation and obeyed unconditionally, becomes a demon.”
Charitable Love
The second paragraph of the section of charitable love is one long extended gardening metaphor. The labor of gardening is essentially symbolically implicated as charity:
“While we hack and prune we know very well that what we are hacking and pruning is big with a splendour and vitality which our rational will could never of itself have supplied.”