Which school of psychology/thought believes that it is impossible to objectively study the mind?

Which school of psychology/thought believes that it is impossible to objectively study the mind?

نفسیات/فکر کا کون سا مکتبہ یہ مانتا ہے کہ دماغ کا معروضی مطالعہ کرنا ناممکن ہے؟
Explanation

Behaviorism focuses on observable behavior rather than studying the mind, as it believes mental processes cannot be objectively measured.

Functionalism studies mental processes in terms of their function in adapting to the environment.

Humanism emphasizes personal growth and self-actualization.