Safe sex

The condom is useful to protect just the body.

If you want to protect the soul too, use the sacrament of matrimony instead.

Be humble

In the field of praxeology, a suspicion of having arrived to a discovery is a strong symptom of insufficient reading rather than of outstanding genius.

Best wishes

I don't dream of a Castro dead, but of a Castro conservative.

Maybe not so different

"In addition to the law of marginal utility, there is another factor influencing the rankings of each individual's value scale. It is obvious that the amount that Johnson will supply at any price is limited by the stock of goods that he has available." Rothbard, Murray. Man, Economy, and State. Page 126.

"Utility then is not the measure of exchangeable value, although it is absolutely essential to it. If a commodity were in no way useful -in other words, if it could in no way contribute to our gratification- it would be destitute of exchangeable value, however scarce it might be, or whatever quantity of labor might be necessary to procure it." Ricardo, David. Principles of Political Economy and Taxation. 1817 -third edition, 1817-. Chapter I, section 1, paragraph 2. Page 17-18.

What is rescuable in the labor theory of value

Every purposeful action aims to improve the value of goods; this is, to bring them closer to the achievement of ultimate ends.

This is true since, given an ultimate end, a good of lower order is more valued than one of a higher order.

Falsifiability in the pure logic of choice

The fundamental axiom of purposeful action isn't itself fasifiable, but every single other axiom in order to unfold a theory based on the scientific method of pure logic of choice (subsidiary axioms) has to be falsified in order to test the validity of a theory derived from such axiom. (1)

(1) Confront against Friedman's The Methodology of Positive Economics. Originally in: Essays in Positive Economics. The University of Chicago Press, 1953.