To find a book on the shelf, philosophy books are shelved in the main collection on the second floor, use the call number listed in the catalog. Most materials in Philosophy have call numbers beginning with B-BD or BH-BJ.
Remember that if you are looking for materials about a certain philosopher, try searching with the philosopher's name as the subject in the advanced catalog search. This will provide you with a list of items about that philosopher, instead of items written by that philosopher. If you want to search for works written by a particular philosopher, search by the philosopher's name in an author search.