Quote: Hooker on skepticism

Joseph Hooker, commenting on an address by Lord Kelvin concerning achievements in mathematics, in a letter to Charles Darwin, August 5, 1871:

I do not think Huxley will thank him for his reference to him as a positive unbeliever in spontaneous generation-these mathematicians do not seem to me to distinguish between un-belief and a-belief. I know no other name for the state of mind that is produced under the term scepticism.