 Overall then, something of a puzzle remains. Hobbes clearly was a materialist about the natural world, but the explicit arguments he offers for the view seem rather weak. Perhaps he just had a good deal of confidence in the ability of the rapidly developing science of the his time to proceed towards a full material explanation of the mind. Just as his contemporary William Harvey, of whom he thought very highly, had made such progress in explaining biological matters, so too (Hobbes might have thought) might we expect further scientists to succeed in explaining mental matters.