What does "sine qua non" mean?

The phrase "sine qua non" is a Latin term that translates to "without which not." It refers to an essential condition or element that is indispensable to the occurrence or existence of something. In other words, something that is sine qua non is critical for a certain outcome or situation. For instance, in legal contexts, proving a sine qua non is often necessary to establish causation, meaning that without that specific element, the case could not proceed. In this context, it emphasizes the fundamental importance, thereby making "the essential element" the correct interpretation of the phrase.