In my most extreme fluctuations I have never been an atheist in the sense of denying the existence of a God ... I think that generally (& more and more so as I grow older) but not always, that an agnostic would be the most correct description of my state of mind.

In regard to the amount of difference between the races, we must make some allowance for our nice powers of discrimination gained by a long habit of observing ourselves.

Mathematics seems to endow one with something like a new sense.

...I believe there exists, & I feel within me, an instinct for the truth, or knowledge or discovery, of something of the same nature as the instinct of virtue, & that our having such an instinct is reason enough for scientific researches without any practical results ever ensuing from them.

To suppose that the eye, with all its inimitable contrivances for adjusting the focus to different distances, for admitting different amounts of light, and for the correction of spherical and chromatic aberration, could have been formed by natural selection, seems, I freely confess, absurd in the highest possible degree.

...all nature is perverse & will not do as I wish it.

The tree of life should perhaps be called the coral of life, base of branches dead; so that passages cannot be seen-this again offers contradiction to constant succession of germs in progress.