Final answer:
Immanuel Kant's moral philosophy emphasized the use of reason to establish universal moral laws through the categorical imperative, which posits actions are moral if they can be universally applied.
Step-by-step explanation:
The Enlightenment philosopher Immanuel Kant posited that an action is moral if it can be applied as a universal principle, a concept central to his moral philosophy known as the categorical imperative. This approach to ethics is rooted in the ability of humans to use reason to make decisions independent of desires and to act with a good will, performing duties out of moral obligation rather than external influences.
Kant's categorical imperative emphasizes that we should "Act only according to that maxim whereby you can at the same time will that it should become a universal law." This is to say, one should act in a way that could be adopted by everyone without contradiction or undermining the action itself.
By using reason to establish moral laws, humans can assert their freedom and dignity, distinguishing themselves from other animals driven by instinct. Through the lens of telos, Kant's objective moral reasoning suggests that actions fulfilling a good purpose, such as helping others, are objectively good. Our reasoning power expands beyond mere utility, requiring an ethical dimension that encompasses our choices, like refraining from lying, which if universalized, maintains trust and the coherent functioning of society.