During these formative years he also discovered the works of Percy Bysshe Shelley. Russell wrote: "I spent all my spare time reading him, and learning him by heart, knowing no one to whom I could speak of what I thought or felt, I used to reflect how wonderful it would have been to know Shelley, and to wonder whether I should meet any live human being with whom I should feel so much sympathy." Russell claimed that beginning at age 15, he spent considerable time thinking about the validity of Christian religious dogma, which he found very unconvincing. At this age, he came to the conclusion that there is no free will and, two years later, that there is no life after death. Finally, at the age of 18, after reading Mill's "Autobiography", he abandoned the "First Cause" argument and became an atheist.