This syllogism is valid because it follows Aristotle's rules of deduction, which require a major premise, a minor premise, and a conclusion that logically follows from the premises.
This syllogism is invalid because it commits the fallacy of affirming the consequent. The fact that penguins have feathers does not necessarily mean that they are birds, as there could be other creatures with feathers that are not birds.
Baroque art features strong contrasts, while Rococo art prefers more subtle transitions
Baroque art is generally larger in scale than Rococo art