No one tests the depth of a river with both feet.
You should not be testing the depth of a river by going into it with your two feet because you don't know how deep you will sink. You could drown. Similarly, before you jump and commit yourself fully into anything, you should have a clear sense of the depth of what you are getting yourself into. Test it one tiny step at a time. If you jump into it without scoping it, you could drown in problems you did not expect.
If you are a consultant, for example, before you accept to do a project, you have to access it by scoping it. This gives you an awareness of the depth of the work you are committing to do.
Note: This interpretation is our opinion. We encourage you to agree, disagree, or provide an alternate interpretation.