This manuscript addresses the gap that exists between modern geoscience and geology, which is caused by the relative isolation in which mainstream geologists have operated and continue to operate. This gap is inevitable, but could be significantly reduced by adopting frontline developments in “Complex System Science” and its geoscience equivalent “Earth System Science”. To aid this process one proposes the use of “Geo-Logic” to express geologic problems explicitly and to impose scientific rigour. This paper is a statement of intent to direct geology into a theoretic direction and demonstrates the effectiveness of the approach with case studies where the theoretic approach was instrumental to the solution of a problem. The use of geo-logic would also serve as common language between geoscientists and aid communication between them.