Final answer:
The philosopher who stated that humanity should always be treated as an end in itself and never as a means only is Immanuel Kant. This instruction is a part of Kant's 'Formula of the End Itself,' which is integral to his deontological moral philosophy, emphasizing individual dignity and worth.
Step-by-step explanation:
The philosopher who said, "so act as to treat humanity, whether in your own person or in that of any other, in every case as an end in itself, never as a means only" is Immanuel Kant. This statement is part of Kant's formulation of the categorical imperative, specifically articulated as the 'Formula of the End Itself.' It is a fundamental principle in Kant's deontological moral philosophy, which emphasizes the inherent dignity and worth of every individual.
Kant's moral philosophy suggests that our actions should be guided by rational maxims that can be universalized. In his 'Formula of the End Itself,' Kant instructs us to treat humanity always as an end and never merely as a means. This principle lies at the heart of Kantian ethics, ensuring that in every interaction and decision, we respect the intrinsic value of every person.
Kant's writings don't mean that we should never interact with others for mutual benefit. However, Kant stresses that in such interactions, we must also respect the other's autonomy and dignity. Therefore, while we can benefit from others' help, we must do so without compromising their ability to act as free and rational agents.