Answer:
always treat a human being as an end in itself, never as a mere means
Step-by-step explanation:
According to Kant, people should act in away that they treat humanity never as a mere means (a way of achieving something) but as an end itself. this means that all of mankind should be treated equally at all times while trying to reduce suffering and saving lives, and that it is important for all of mankind to be respected. Kant by this principle is saying that everyone should be rational in treating each other and themselves.