Changing field from Computer Science to Philosophy I am a Computer Science graduate and I have been realising that my true passion lies in Philosophy, as for the past 5 or 6 years (I am 26) I have been constantly asking questions about life, conciousness, the universe and the relationship between them. I am also in the process of writing a book which can be considered as Philosophical, although I am not yet quite sure whether it will be Philosophical Fiction or Non Fiction. 

My question is, is it possible to continue as a graduate and start a Masters or Doctorate in Philosophy? Since I would like to become a professor so I can help others pursuing answers to such questions. As already mentioned, I would also like to start writing unfortunately, in our current era, it is very difficult to be taken seriously if you do not have academic background on that field. 

From what I am reading, this might not be possible since Philosophy is an ancient field and hence there is the usual sequence of degree, masters and PhD. For instance, some new fields, such as neuroscience do not have any directly related degrees and hence you can transition to them from other fields.

If this is not possible, will I be taken seriously if I transform my book into a paper (assuming it is actually a good book) and be allowed to start a PhD without any previous academic philosophical background? My current targets are either Oxford University or UCL.

Looking forward for your response.
Since you're interested in life and consciousness, you might want to explore cognitive science (including artificial life), which draws from philosophy, artificial intelligence, neurology, and other fields. Your computer science background could help you enter a program like this, and once in, you could take philosophy courses to strengthen your background in that area. Perhaps you could do an MSc in cognitive science, and then you might have the background to enter a PhD program in philosophy.