On What Matters
| Author | Derek Parfit |
|---|---|
| Language | English |
| Subject | Ethics |
| Publisher | Oxford University Press |
Publication date | 26 May 2011 |
| Media type | Print (Hardcover) |
| Pages | 1,928 |
| ISBN | 978-0-19-926592-3 |
On What Matters is a three-volume book of moral philosophy by Derek Parfit. The first two volumes were published in 2011 and the third in 2017. It is a follow-up to Parfit's 1984 book Reasons and Persons. It has an introduction by Samuel Scheffler.