  Even if Fs would be non-interfering in Schiffer’s sense, the postulation of Fs logically conflicts with some consistent theories, e.g., ‘There are no Fs’. Schiffer places severer constraints on the denial of entities than on the acceptance of them.  Suppose Fs would be non-interfering. Then adding them would not add information about non-Fs. But suppose also that denying Fs would not add information about non-Fs. Why isn’t this a reason to deny Fs?  So, in this sense, the theory denying Fs passes a corresponding conservativeness test.