Here's why:

* Science relies on empirical evidence: Science uses observation, experimentation, and data analysis to understand the natural world. Ethics, on the other hand, deals with moral values and principles, which are not directly observable or measurable.

* Science seeks objective truths: Science aims to discover objective truths about the universe, independent of personal opinions or beliefs. Ethics, however, involves subjective judgments about right and wrong, which can vary between individuals and cultures.

* Science is falsifiable: Scientific theories can be disproven through experimentation. Ethical principles are not subject to falsification in the same way.

While ethics is not a science, it can be studied systematically and rigorously:

* Philosophical ethics: This branch explores the foundations of morality, analyzes different ethical theories, and investigates the nature of moral judgments.

* Applied ethics: This area applies ethical principles to specific real-world issues, such as medical ethics, business ethics, or environmental ethics.

So, while ethics is not a science in the traditional sense, it is a complex and important field of study that employs critical thinking and reasoned argumentation.