After many months of reading Aristotle's philosophy and commentary thereon, recently I decided to re-read Ayn Rand's essay "The Objectivist Ethics", wherein Rand criticizes Aristotle for not considering ethics to be an exact science. I have no idea what that would mean. Consider, for instance, the relevant Wikipedia page (not necessarily reliable, but often a good start), which states:
The exact sciences, sometimes called the exact mathematical sciences are those sciences "which admit of absolute precision in their results"; especially the mathematical sciences. Examples of the exact sciences are mathematics, optics, astronomy, and physics, which many philosophers from Descartes, Leibniz, and Kant to the logical positivists took as paradigms of rational and objective knowledge. These sciences have been practiced in many cultures from Antiquity to modern times. Given their ties to mathematics, the exact sciences are characterized by accurate quantitative expression, precise predictions and/or rigorous methods of testing hypotheses involving quantifiable predictions and measurements.
How in the world did Rand think that ethics could be an exact science, subject to testing of falsifiable hypotheses, precise mathematical measurement, and quantifiable predictions? What would an ethical hypothesis look like? What would it mean to mathematically measure courage or moderation or wisdom? Are human beings within the realm of prediction rather than, at best, the realms of dependability or trustworthiness? The notion of ethics as an exact science strikes me as unmoored from human existence and experience.