A shear separation system or method uses shear lift forces and permeate drag forces to separate substances having a size less than a predetermined separation size from substances having a size greater than the separation size. The balance of the drag forces and lift forces affects a predetermined separation size in that the balance of forces reads the transmembrane passage of substances larger than the separation size yet allows substances smaller than the separation size to pass through the permeable membrane. The shear separation device, method and system can be employed to separate or concentrate from a process fluid substances larger or smaller than the predetermined separation size.