On The Trader Principle

Ayn Rand wrote on page 31 (1964 Centennial Edition) of The Virtue of Selfishness: “The principle of trade is the only rational ethical principle for all human relationships, personal and social, private and public, spiritual and material.”

I think the trader principle is an excellent moral guide with wide application, but believe that her use of "only" and "all" overstate the case. In a typical trade each party provides the counter-party with something that can be called a cost to the said party. For example, I buy a new car from a dealer. The cost to me is the money I pay. The cost to the dealer is what he paid for the car plus some overhead.

I challenge her use of "only" and "all" for three different sorts of actions -- raising children, teamwork, and charitable giving.

When parents feed, clothe, educate, and otherwise provide the basics of life to their young children, what do the children trade, or give up, in return that is of equal or roughly equal value? In other words, what is the child’s cost that is the counterpart of the car dealer’s cost? 

Suppose two men use a two-man saw to cut down a tree and further cut it into smaller pieces. Far more examples of teamwork are easy to imagine, and occur frequently in work situations. Each worker does his or her part, which may or may not be the same, to achieve a common goal.  How is such teamwork a trade like my buying a car?

Suppose I contribute some money to disaster relief or to benefit military veterans. Another party X, unknown to me, benefits from the money contributed. How is that a trade like my buying a car?

By the way, I reject the notion that a trade-off implies a trade.