Haji, IshtiyaqueYao, Bokai2017-04-262017-04-2620172017Yao, B. (2017). Some Puzzles About Ability (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/27830http://hdl.handle.net/11023/3720This thesis aims to solve two metaphysical puzzles about ability. The first belongs to the free will debate: is determinism compatible with the ability to do otherwise? The second pertains to time travel: what things can a backward time traveler do in the past? By introducing two principles about an agent’s ability regarding the past, I defend the following modal principle about ability: what an agent can do must be compossible with the past. This principle generates solutions to the two puzzles.engUniversity of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.PhilosophyMetaphysicsAbilityFree WillTime Travelmaster thesis10.11575/PRISM/27830