Systems are collections of interrelated things. These things could be mechanical controls, organizations, computers, ideas, processes, social roles, or anything else that can be seen to interact for a purpose or goal. Systems science studies these things and their interrelation in order to derive transdisciplinary insights and deep understanding, often leading to the root causes of problematic phenomena.
The systems thinking that systems science engenders differs from traditional scientific approaches as it provides a framework for studying wholes, instead of parts. Systems thinking is often understood in opposition to Enlightenment reductionist thinking, when, if fact, it should be understood as a complement to it.