[discouraging the publication of ill-advised speculations]
[…] When a man has laboured hard in science & has proved that he is capable of original research, he may [some]times indulge in speculation [&] the public will indulge him. But even in this case it is a common error to speculate too largely, for speculation is far easier than observation or experiments […]
Please cite as “DCP-LETT-13866A,” in Ɛpsilon: The Charles Darwin Collection accessed on