Software patentability and practical utility: What's the use?

The debate over whether software is appropriate subject matter for patent protection continues to rage, without any clear resolution in sight. The European Patent Convention attempts to draw this distinction by excluding software programs from patent protection unless they have a ‘technical effect’. US law requires that a software program have a ‘practical utility’ to constitute patentable subject matter. Both such requirements fail to provide clear guidance in hard cases because they merely beg the question of what constitutes a ‘technical’ effect or a ‘practical’ utility. I recommend that software patent claims instead be evaluated in terms of three kinds of utility or effects: (1) physical utility, which refers to the direct physical effects of an invention, such as the movement of gears and levers in a mechanical cash register; (2) logical utility, which refers to the information processing tasks performed by an invention, such as the mathematical operations performed by a cash register; and (3) application utility, which refers to the usefulness of the invention to the end user, such as the increased accuracy and reduced calculation time made possible by a cash register. In particular, the physical utility requirement would require the applicant to demonstrate that the claimed software is susceptible of embodiment in a tangible form, the logical utility requirement would require the claimed software to be defined clearly in terms of the information processing steps it performs, and the application utility requirement would require the applicant to provide an industrial application of the claimed software. Furthermore, patent examiners and judges should be required to evaluate software patent claims expressly in terms of each kind of utility. This would clarify the basis for the decision in each case and avoid the now-common conflation of one kind of utility with another, thereby focusing any dispute over subject matter patentability on the particular kind of utility whose satisfaction is in question.