One view of "what four lessons about life" poet Roger McGough is teaching in his amusing and ironic poem "The Way Things Are" is that he is teaching lessons about life, time, reality, and wisdom. McGough's wonderful ironic tone ("Pebbles work best without batteries. / The deckchair will fail as a unit of currency.") develops with a masterly hand the image of a caring and loving father explaining to a small child the mysteries and intricacies of life and living ("Even though your shadow is shortening / it does not mean you are growing smaller.") While finding four lessons amidst the symbolic charming and ironic examples ("When the sky is looking the other way, / do not enter the forest.") may be a bit of a challenge, I can suggest the following.
McGough intends to teach about age and the frailty of life. This is shown in his references, for example, to old people walking slowly, to candles crying, and to the "last goodbye." In these brilliantly contrived references, he is showing that life deteriorates along the way, that life does have pain, and that the last goodbye may be permanent instead of an au revoir, until we see each other again.
McGough also intends to teach about time and history:
For centuries the bullet remained quietly confident
that the gun would be invented.
A drowning surrealist will not appreciate
the concrete lifebelt.
Along with the above topics, he explains that old people don't, in fact, have lots of time and that what is of value today (craft fair), with time, may be valueless tomorrow, just as activities "pall" (loose the pleasure) over time ("The thrill of being a shower curtain will soon pall.")
The two biggest lessons taught are that of science and reality as well as safety and wisdom. McGough addresses science, for example, in mentioning what is not the cause of wind, the propulsion potential of a lighthouse, and the ephemeral nature of moonlight. He addresses reality by declaring the opposition of a surrealist to that which is concrete, the ineffectiveness of bubblegum on hair, and that the exercise of great responsibility leaves scars over time.
Personal safety and wisdom actually seem to get the greatest attention from McGough. He admonishes, for example, against becoming a jailer unless one is very wise; that losing a glove is the same as losing a pair, which can be read as a metaphor for other things like relationships; and that there is no "trusting hand" to catch a "falling star." He ends by apologizing that this is the way things are.