In order to be falsifiable it must be feasible to obtain the evidence that would disprove the theory. For example, if you claim that there is a small green marshmallow floating in space somewhere in the Andromeda Galaxy, you would need to check every square inch of the Andromeda Galaxy at the same time to disprove the claim. This isn't feasible so the claim isn't falsifiable. A possible 14th characteristic of a good theory is that it be consistent with established knowledge. We left this out because it would seem like an excuse to defend the status quo from new theories that overturn invalid assumptions in a field.
Can be supported or refuted with empirical evidence.
Could be proven false if it were false.
Supported by empirical evidence.
Applicable to a range of contexts and situations.
Internally consistent and logical.
Offers new explanations.
Applicable to current issues or the future of a field of study.
Parsimony & Economy
Based on fewer assumptions than alternative explanations.
High degree of agreement in the relevant field that the theory is valid.
Provides specific explanations.
Not influenced by bias.
Experiment design, data and other relevant information is openly disclosed.
Open to Challenge
The theory is defended but with an open mind. The theory can change with new evidence.