NWR: Science starts with clear definitions.
Not always. Biology is rarely captured (in a clean sense) by definitions. Any biological definition becomes fuzzy and unclear when you probe deeper.
Sciences generally have both clearly defined terms and vague terms. There can even be vague terms in mathematics.
The clearly defined terms are needed to set the criteria for collecting and evaluating facts. For example, a traditional part of biology has been classification (systematics). This requires clear criteria on which to base the classification.
The general term "species" may be somewhat vague. The defining characteristics of particular species are usually clear. Where to draw the boundary line between two species may be uncertain, and might require an arbitrary decision. But once that decision has been made, the criteria are usually clear. I'll grant, however, that nature is messy, and there can sometimes be ambiguity.
The problem I was trying to point out for ID, is that the basic terminology of the field is not defined well enough to set the criteria that are needed for collecting data.