Whatever part of the animal fabric whatever series of muscles, whatever viscera might be selected for comparison the result would be the same the lower Apes and the Gorilla would differ more than the Gorilla and the Man.

The only medicine for suffering, crime, and all other woes of mankind, is wisdom. Teach a man to read and write, and you have put into his hands the great keys of the wisdom box. But it is quite another thing to open the box.

The dogma of the infallibility of the Bible is no more self-evident than is that of the infallibility of the popes.

The ultimate court of appeal is observation and experiment... not authority.

The birth of science was the death of superstition.

It is an error to imagine that evolution signifies a constant tendency to increased perfection. That process undoubtedly involves a constant remodeling of the organism in adaptation to new conditions; but it depends on the nature of those conditions whether the direction of the modifications effected shall be upward or downward.

I have always been, am, and propose to remain a mere scholar. All that I have ever proposed to myself is to say, this and this I have learned; thus and thus have I learned it; go thou and learn better; but do not thrust on my shoulders the responsibility for your own laziness if you elect to take, on my authority, conclusions the value of which you ought to have tested for yourself.