Complex sentence: Professional psychologists mistrust these as much as they mistrust what they see as popular psychology, as quackery and as pseudoscience; but these systems do generally represent, at least, some relatively systematic attempt to understand human thought, emotions, behavior, and the psyche.
Split into simpler sentences: Professional psychologists mistrust these as much as they mistrust what they see as popular psychology, as quackery and as pseudoscience. MOst of these systems do generally represent, at least, some relatively systematic attempt to understand human thought, emotions, behavior, and the psyche.