
Devon E. answered 04/29/19
Versatile, experienced multi-subject tutor with PhD in Biology
From the perspective of a scientist: Considering that a thesis or dissertation should be your original work, there should be very little that isn't yours. If you are discussing another's work in your introduction or to justify the project, you should be summarizing. Paraphrasing (and less quoting) should be used only if you need to convey a specific aspect from your source that would be lost if you are only summarizing.