Your construct of, "if you can't come up with something else it must be ID." could be used as the very definition of an argument from ignorance.
Since you're a lazy one, here you go:
Argument from ignorance (
Latin:
argumentum ad ignorantiam), also known as
appeal to ignorance (in which
ignorance stands for "lack of evidence to the contrary"), is a
fallacy in informal logic. It asserts that a proposition is true because it has not yet been proven false (or vice versa). This represents a type of
false dichotomy in that it excludes a third option, which is that there is insufficient investigation and therefore insufficient information to prove the proposition satisfactorily to be either true or false. Nor does it allow the admission that the choices may in fact not be two (true or false), but may be as many as four,
- true
- false
- unknown between true or false
- being unknowable (among the first three).[1]
In debates, appeals to ignorance are sometimes used to shift the
burden of proof.
The fallaciousness of arguments from ignorance does not mean that one can never possess
good reasons for thinking that something does not exist, an idea captured by philosopher
Bertrand Russell's teapot, a hypothetical china teapot revolving about the sun between Earth and Mars; however this would fall more duly under the arena of
pragmatism[
vague], wherein a position must be demonstrated or proven in order to be upheld, and therefore the burden of proof is on the argument's proponent.[
citation needed] See also
Occam's razor ("prefer the explanation with the fewest assumptions").
The
argument from incredulity is a
logical fallacy that essentially relies on a lack of imagination in the audience.
The general form of the argument is as follows.
- Minor premise: One can't imagine (or has not imagined) how P could be so.
- Major premise (unstated): If P, then one could imagine (or would have imagined) how P could be so.
- Conclusion: Not-P.
As a syllogism this is valid. The fallacy lies in the unstated major premise. If a state of affairs is impossible to imagine, it doesn't follow that it is false; it may only mean that imagination is limited. Moreover, if no one has yet managed to imagine how a state of affairs is possible, it doesn't follow that no one will ever be able to.