In the case of Union Edge Setter Company v. Keith (1890), the U.S Supreme Court was tasked with determining whether a patent infringement had occurred. The Union Edge Setter Company claimed that Mr. Keith, who held patents for certain improvements in machines used to set saw teeth, had infringed upon their own patented machine design which performed similar functions. After examining both designs and considering expert testimony, the court found significant differences between them and concluded that no infringement had taken place as they were not identical nor equivalent in function or operation despite performing similar tasks. Therefore, it ruled in favor of Mr. Keith.

In the dissenting opinion for Union Edge Setter Company v. Keith, it was argued that the patent in question should not have been invalidated. The dissenting justices believed that there was sufficient novelty and non-obviousness in the invention to warrant its protection under patent law. They disagreed with the majority's interpretation of prior art, arguing that previous inventions did not disclose or suggest all elements of Keith's patented device. Furthermore, they contended that even if some aspects were found in earlier patents or publications, combining these references required a level of inventiveness deserving legal protection itself. Therefore, they concluded that Keith’s invention met all requirements for patentability and his rights as an inventor should be upheld.