Policies can be configured with positive or negative logic. Briefly, you can use this option to define whether the policy result should be kept as it is or be negated.

For example, suppose you want to create a policy where only users not granted with a specific role should be given access. In this case, you can create a role-based policy using that role and set its Logic field to Negative. If you keep Positive, which is the default behavior, the policy result will be kept as it is.