You reminded me of something I think no one has mentioned yet:

In philosophy and rhetoric, the principle of charity or charitable interpretation requires interpreting a speaker’s statements in the most rational way possible and, in the case of any argument, considering its best, strongest possible interpretation. In its narrowest sense, the goal of this methodological principle is to avoid attributing irrationality, logical fallacies, or falsehoods to the others’ statements, when a coherent, rational interpretation of the statements is available.

From: Principle of charity.

Applying this, I think we can interpret the *independent thinking" not as thinking without conditioning factors but as what is known as “critical thinking”.

Although some feelings are malleable through thinking, but yeah, others come from (and can only be worked by) different places (including the health of our body).