Sufficiency of Grounds

A conclusion needs to be supported by as many relevant claims as necessary to convince the audience. Premises are insufficient for the conclusion if they:

i) do not supply enough systematically gathered evidence,

ii) do not supply a sufficient sample of the various relevant kinds of evidence, or

iii) ignore the presence or possibility of contrary evidence.



Sufficiency Problems:


1. Hasty Generalization: Coming to a conclusion based on insufficient evidence, or too few examples.


2. The "Spotlight" Fallacy: Occurs when a person uncritically assumes that all members or cases of a certain class or type are like those that receive the most attention or coverage in the media.


3. Composition Fallacy: committed when a conclusion is drawn about a whole based on the features of its constituents when, in fact, no justification provided for the inference.