"If you haven't written it, you haven't done it."
David Lindsay, 1999, A Guide to Scientific Writing, Australia, Pearson Education

This remark is highly relevant to scientific writing. But how to write whatever "it" is can be a problem, since "it" can take many forms.

Observation: a bold statement
Interpretation: what the facts or events suggest
Evidence:
Acknowledgement: I have taken sentences and examples from Grotzinger et al., 2007, Understanding Earth, New York, W. H. Freeman and Company.