Writing a senior thesis can be an incredibly enriching experience. In writing a thesis you will get the chance to explore a question of your own design. This question can be on a topic that has always interested you and intrigued you. It can be on a question that you have wanted to study but haven't yet had the opportunity. You will have a whole year to define that question and seek out an answer.
Working on your thesis will likely be the most challenging academic experience you have had, and may well be the most rewarding. You will learn what it is to commit to a major project and bring it to completion. Your thesis work will be valuable whatever you do after graduation, but it will also introduce you to a central component of philosophical practice: the intensive and sustained engagement with a philosophical problem in all of its varied aspects. Lastly, it may help you decide whether you want to continue your study of philosophy in graduate school.