policy. The economist knows the scale of values only through the reality of action. Furthermore, most of the consequences of a policy take time, and people may refuse to change their minds, even after acknowledging the praxeological chain of consequences. Rothbard critiques the idea that praxeology (the study of human action) can prove that laissez-faire policies will lead to prosperity and abundance, and government intervention will lead to conflict and impoverishment. While this may be true for most people, it is not the case for all. For example, some people may prioritize equality of income, even if it means sacrificing wealth and efficient production. Rothbard argues that this competing value cannot be criticized by utilitarian economists, as they must favor the majority achieving their chosen goals. Additionally, some types of statist intervention may have little or no cumulative effect and may even have very little impact on prosperity. Therefore, the argument that intervention will eventually lead to socialism is not entirely satisfactory. Chapter 27, "Isaiah Berlin on Negative Freedom", critiques Sir Isaiah Berlin's concept of negative liberty, which is defined as the absence of interference with a person's sphere of action. Rothbard argues that Berlin's vague definition led to confusion and the absence of a systematic and valid libertarian creed. Berlin's original concept of negative liberty is flawed because "a man can be held to be 'free' in proportion as his wants and desires are extinguished, for example by external conditioning". Later, Berlin defines freedom as "the absence of obstacles to possible choices and activities." However, this comes close to confusing "freedom" with "opportunity" and "to scuttling Berlin’s own concept of negative freedom and replacing it with the illegitimate concept of 'positive freedom.'" "Berlin's fundamental flaw was his failure to define negative liberty as the absence of physical interference with an individual’s person and property, with his just property rights broadly defined." Rothbard also argues that Berlin's "assaults on laissez-faire as somehow injurious to negative liberty" are absurd and self-contradictory. "Berlin is really explicitly scuttling the very concept of 'negative' liberty on behalf of concepts of positive power or wealth." Chapter 28, "F.A. Hayek and The Concept of Coercion", critiques F.A. Hayek's political philosophy on individual liberty, specifically his flawed definition of coercion as including both physical violence and peaceful, non-invasive actions. Rothbard argues that this leads to confusion and self-contradiction in Hayek's arguments, and fails to distinguish between aggressive