Final answer:
Kant believed in absolute moral laws called categorical imperatives, which do not allow for exceptions. Lying is always wrong according to Kant because it cannot be universalized without eroding trust. His philosophy mandates that certain duties, such as telling the truth, must be followed by all rational beings.
Step-by-step explanation:
Immanuel Kant, the Enlightenment philosopher, held a rigorous approach to moral philosophy. In your question, you're wondering about whether, according to Kant, every moral rule has its exceptions. The answer is False. According to Kant's ethical system, there are categorical imperatives; these are absolute moral laws that do not admit exceptions. Kant divided imperatives into hypothetical and categorical. A categorical imperative is a universal moral law that applies to all rational beings and is not dependent on any desire or end. The classic example Kant uses is the duty to tell the truth. Kant suggested that a maxim (or rule for acting) is moral only if it can be universalized, meaning it should apply to everyone equally and should work as a universal law. For example, lying would be immoral because if everyone lied, trust and communication would break down.
The formulation of the categorical imperative insists that you "Act only according to that maxim whereby you can, at the same time, will that it should become a universal law." Kant also discussed perfect duties, which are those we are obliged to follow without exception, such as not lying and not stealing. Another aspect of his moral philosophy is the humanity formulation, which commands us to treat humanity, in ourselves and others, always as an end and not merely as a means.