In the case of American Car & Foundry Company v. Kettelhak, the U.S Supreme Court in 1914 ruled on a dispute involving patent rights and infringement claims. The plaintiff, American Car & Foundry Company (ACF), accused Kettelhak of infringing upon their patented design for a railway car undercarriage. However, the defendant argued that ACF's patent was invalid as it lacked novelty and was not an original invention but merely an aggregation of old elements already known in prior art. The lower court sided with Kettelhak, declaring ACF's patent void due to lack of inventiveness. Upon appeal to the Supreme Court, this decision was upheld; however, they clarified that while combining existing technologies or ideas does not necessarily constitute invention deserving of a new patent claim unless such combination results in some new or improved function or use which is unexpected from such union - termed "synergistic effect". In this case though, no such synergistic effect had been demonstrated by ACF for its railway car undercarriage design thus affirming its lack of novelty and non-patentability.

In the dissenting opinion for American Car & Foundry Company v. Kettelhak, it was argued that the majority's decision to uphold a lower court ruling in favor of an injured worker was incorrect. The dissent contended that there were significant issues with how evidence had been presented and interpreted during trial proceedings. Specifically, they believed that certain pieces of evidence should not have been admitted due to their speculative nature or lack of relevance to the case at hand. They also disagreed with how testimony from expert witnesses had been handled, arguing that these individuals did not possess sufficient knowledge or expertise on key aspects related to the incident causing injury. Furthermore, they expressed concern over instructions given by judges which could potentially mislead jurors into making decisions based on sympathy rather than facts and law.