"Since presumption of permissibility

is the dominant rule,  Muslims are not required to prove that things are permissible; only claims of prohibition demand proof. Today, many Muslims take it lightly to declare things forbidden; the opposite was true for the companions and the authoritative voices of Islamic law. Their inhibition, to the extent that they may be described as having inhibitions, was to pronounce things forbidden unless they were not already clearly known to be so. When the great legal scholars of the past took the decision to classify something as forbidden based on personal interpretation, they based their arguments on conclusive evidence, and even then they made their decisions with marked hesitation.

-from pg. 27 of "Living Islam With Purpose" by Dr. Umar F. Abd-Allah