2. Permissions are express or implied. 1. Express permissions derogate from something which before was forbidden, and may operate in favor of one or more persons, or for the performance of one or more acts, or for a longer or shorter time. 2. Implied, are those, which arise from the fact that the law has not forbidden the act to be done. 3. But although permissions do not operate as laws, in respect of those persons in whose favor they are granted; yet they are laws as to others. See License.