What is the 'psychology as a science' debate and can you explain it?

The Psychology as a science debate is asking students to consider how scientific the study of psychology is. Science is defined by its method (the scientific method is a phrase commonly used by scientists). This scientific method is the following process: Hypothesis -> valid experiment -> Results (repeated for reliability) -> statistical analysis -> journal article -> peer review. So it can be defined as the study of the natural world through observation and experiment.So what makes psychology scientific?1) It is a research based discipline.2)Psychology usually uses the scientific method and, if the study has sufficient controls, this can show cause and effect.3)Psychologists generate a hypothesis which can be empirically tested (tested with evidence).4)Psychology, especially biological psychology, uses scientific equipment such as MRI machines.5)Psychology produces quantitative data.Why is psychology not a science?1)Psychology studies humans, which are highly complex and are usually aware they are being studied. This means its very difficult to account for all extraneous variables, and people may alter their behavior unconsciously if they know they're being studied. This reduces validity and cause and effect. 2)Psychology largely studies 'The mind'. This isn't directly observable and interpretations of data can be subjective. However biological psychology isn't as subjective as the brain is directly observable.3)Due to the difficulty establishing complete cause and effect due to the previous 2 points, psychology can't be accurately defined as factual, but instead can be defined as probabilistic. 4)Some theories are very subjective (Freud)5)Uses qualitative data.