When people judge efficient means and legitimate ends at the same time, both can be considered as good. However, when ends are judged separately from means, it may result in a conflict: what works may not be right; what is right may not work. Separating the criteria contaminates reasoning about the good. Philosopher John Dewey argued that separating criteria for good ends from those for good means necessarily contaminates recognition of efficient and legitimate patterns of behavior. Economist J. Fagg Foster explained why only instrumental value is capable of correlating good ends with good means. Philosopher Jacques Ellul argued that instrumental value has become completely contaminated by inhuman technological consequences, and must be subordinated to intrinsic supernatural value. Philosopher Anjan Chakravartty argued that instrumental value is only legitimate when it produces good scientific theories compatible with the intrinsic truth of mind-independent reality.