Eddington argued that the value of the fine-structure constant, α, could be obtained by pure deduction. He related α to the Eddington number, which was his estimate of the number of protons in the universe. This led him in 1929 to conjecture that α was exactly 1/136. He devised a "proof" that N Edd = 136 × 2, or about 1.57 × 10. Other physicists did not adopt this conjecture and did not accept his argument.