Tolerance at all levels of complexity in the brain involves “learning” in the sense of the acquisition of compensatory adaptations to the consequences of the presence of a drug-produced disturbance in function. Depending on the function, species, and dose of cannabis, “tissue tolerance,” behaviorally augmented (to provide the presence of the disturbed function) or not, develops at different rates or not all (e.g., to impairment of the logical sequence of thoughts, to which no tolerance has yet been demonstrated).