To S. P. Woodward   6 March [1860]¹

My dear Sir.

I will not fail to speak what I think about your high merits if consulted by any of the Senate.²

I should be very glad of any criticisms on the origin— I imagine you have not finished it. I suspect that we are at cross purposes about “typical” & “specialisation”— I look at the latter (ie. specialisation of organs) with all physiologists as a great advantage to each being & therefore as not likely to lead to their extinction.—   And with respect to Typical—I observe that Naturalists use it in two very different senses; hence I have almost entirely or entirely avoided its use—

You will see something about the preservation of old former forms in islands & in isolated situations—a subject on which I could have much enlarged.—   I doubt whether you understand my notions on extinction; but when we meet you can explain what you mean by “Specialisation” & “typical”.

The fair way to view the argument of my book, I think, is to look at Natural Selection as a mere hypothesis (though rendered in some degree probable by the analogy of method of production of domestic races; & by what we know of the struggle for existence) & then to judge whether the mere hypothesis explains a large body of facts in Geographical Distribution, Geological Succession, & more especially in Classification, Homology, Embryology, Rudimentary Organs    The hypothesis to me does seem to explain several independent large classes of facts; & this being so, I view the hypothesis as a theory having a high degree of probability of truth. All turns on whether the above classes of facts seem to you satisfactorily explained or not.— The difficulties are great; but they concern the “imperfection of the Geological record,” “means of distribution” & “possibility of transitions of organs”    And on these classes of facts we are confessedly ignorant, & we do not know how ignorant.— I simply believe that we are far more ignorant than any one supposed—

Forgive me for troubling you with this harangue, for I should very much like to stagger you,—to pervert you or any good man ought & must require months of self reflection.³

Yours very sincerely | C Darwin.

It may be a vain & silly thing to say, but I believe my Book must be read twice carefully to be fully understood.— You will perhaps think it by no means worth the labour.