Whether vs. Whether Or Not

'Whether' and 'whether or not' are both conjunctions used to introduce a conditional clause. They indicate that an event relies on occurrence of another event. 'Whether' is a conjunction that introduces a conditional clause when there are two or more alternatives or options, and the speaker wants to express doubt or uncertainty about which one to choose. 'Whether or not', on the other hand, is a conjunction that introduces a conditional clause when there is a single alternative or option, and the speaker wants to express doubt or uncertainty about whether it will happen or not. Compare the examples:

Take another look at the examples above. As you can see, the focus of the sentence can differ depending on which conjunction is used. 'Whether' focuses on the alternatives or options being considered, while 'whether or not' focuses on the uncertainty or doubt about a particular event or outcome. However, in many cases, they can be used interchangeably without changing the meaning of the sentence.

In some formal writing contexts, such as academic or legal writing, it may be preferable to use 'whether' instead of 'whether or not', because it is more concise and less wordy.