"Everything Psychological is Biological" refers to the idea that everything psychologically occurring within our mind is a result of a biological situation or stimulation. Our mind's activity is determined through the biological means of systemic nerve impulses. Our biological composition determines our psychological factors. For example, our actions and personality exist the way it does because of our biological makeup, such as the genetics received from our parents, and not due to outside factors like the people we grew up around.
To put it simply, the phrase "Everything Psychological is Biological" summarizes the theory that our psychological decisions function the way they do as a result of our biological constitution.
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