"I understood quite a good deal of _First Principles_, but his _Biology_ took the wind out of my sails, and his _Psychology_ left me butting around in the doldrums for many a day.
I honestly could not understand what he was driving at.

I put it down to mental deficiency on my part, but since then I have decided that it was for want of preparation.

I had no proper basis.

Only Spencer and myself know how hard I hammered.

But I did get something out of his _Data of Ethics_.