It is not necessary for students to have studied any Philosophy before reading the subject at Cambridge, and Part IA of the Philosophy Tripos is taught on the assumption that they have not done so. Any combination of arts and science A-level subjects is acceptable. A few undergraduates reading Philosophy at Pembroke take a year off after completing school before coming up to university, and the College encourages this, with the understanding that it is not always possible or desirable. Pembroke aims to admit two undergraduates a year to read Philosophy, although numbers vary each year reflecting the quality of the field. Numbers of applicants are usually in single figures. Candidates who are shortlisted for interview will have two interviews, one with the Director of Studies, who is usually accompanied by another specialist member of staff, and one with the Admissions Tutor or other non-expert academic. They will also sit a one-hour written assessment, usually the evening before the interviews. This will be composed of multiple choice logic problems and an essay; no special preparation for it is necessary. Further information about the written assessment can be found on the University of Cambridge website: www.cam.ac.uk/assessment. The interview with the Director of Studies will probably consist largely of a friendly discussion on a philosophical question.
Since Philosophy is not usually taught in schools, it is not always easy for students to tell whether they are suited to the subject and whether it is suited to them. It is a good idea, to explore the Philosophy website, where you can find all sorts of useful information, including lecture notes and reading lists for current philosophy students. It is also essential, of course, to read some Philosophy books before making a decision about the subject; below you will find a list of books which give a good introduction to the subject. More generally, if you enjoy marshalling arguments pro and con, solving puzzles, arguing about rather abstract questions, or trying to define things, then you might well find that Philosophy is the right subject for you.
Logic W Hodges: Logic (Penguin).
Further enquiries should be addressed to Admissions Office at Pembroke College.
See also the page about Philosophy on the University website.