Man himself cannot express love and humility by external signs, so plainly as does a dog, when with drooping ears, hanging lips, flexuous body, and wagging tail, he meets his beloved master.

I have at least, as I hope, done good service in aiding to overthrow the dogma of separate creations.

I cannot see ... evidence of design and beneficence ... There seems to me too much misery in the world.

Hence, a traveller should be a botanist, for in all views plants form the chief embellishment.

It appears to me (whether rightly or wrongly) that direct arguments against Christianity and theism produce hardly any effect on the public; and freedom of thought is best promoted by the gradual illumination of men's minds, which follows from the advance of science.

Nothing is easier than to admit in words the truth of the universal struggle for life, or more difficult - at least I have found it so - than constantly to bear this conclusion in mind...We behold the face of nature bright with gladness...We do not see, or we forget, that the birds which are idly singing round us mostly live on insects and seeds, and are thus constantly destroying life.

Nothing exists for itself alone, but only in relation to other forms of life