No 2

Sir John Frederick's reply

My dear Sir ―― I am not at all surprised that you shouldhave been somewhat startled by that passage in my addressin which I speak of M. Comte's argument in favor of thenebular hypothesis ―― still less that you should stand forward
in his defence until he can reply for himself. I should (of course)
have sent him a copy of my speech had I known how
to address him. Perhaps you know, & will in that case oblige
me by forwarding to him one of two copies of the Athenaeum
in which it appeared & accepting the other yourself. ―― they arecorrected for some very absurd errors of the press. One affects
the subject in question.
As to that subject, I do not think you will find mycriticism of M. Comte’s position quite so easily disposed ofas you appear to regard it. It was and is my deliberate
opinion (formed it is True from the perusal of no other workof M. Comte's than his Phil. Pos.) that his whole reasoning
as there stated is really vitiated by the fallacy, which(whether clearly or not) I have endeavored to expose, &I must be met by much stronger arguments (excuse theexpression) than those you adduce, to drive me from that
persuasion.
If, in some other work which I have not read, M. Comte
have gone fairly into the formidable problem of the coolingand shrinking process of the Nebulous hypothesis ―― if he haveshown, without making any arbitrary assumptions, orsuperadding any additional hypothesis, that, as a necessary consequence
from the shrinking of dimension & rearrangement of parts resulting
from the abstraction of heart, the period of rotation of the sun’s surface
on its axis at every instant during the shrinkage or at least at
those instants when the planets were detached, must have been
proportional to the32

power of its equatorial diameter at that or thoseinstants ―― if he have done so, I at once admit, he has proved thenebulous hypothesis, & must rank with Newton as a discoverer and above
Laplace and Lagrange as an analyst. But that is quite another case;1

& for that case (improbable, nay impossible as I conceive it to be in thepresent state of physical knowledge) I have expressly provided by theexpression in my note appended to the passage in my address. ―― "if
his fundamental principle be really what he states" (viz. a mere
combination of𝑉2
𝑅with Newton’s𝑀𝑅2). But it is to me inconceivablethat if he had gone into or even made any tolerable attempt at thedynamical problem in question leading him to each conclusion, he shouldhave no understated, or rather so completely misstated his case, as onthat supposition he must have done in the Cours de Ph. Pos.
Reterning to your own work ―― I hope you will excuse me if I remark(& the remark is in no way in compatible with the general high opinion
I have formed & expressed of it in a philosophical point of view) that I
regard as the least felicitous portions of it, those in which points ofphysical science & mathematics are touched upon. I should have noobjection if you received it, to specify some particular instances whichhave occurred to me inter legendum to which this remark applies
provided always that I were distinctly understood as only pointing them out
for your own reconsideration, & not as holding myself obliged to defend, oreven to explain my objections against them should I be so unfortunate asto state them obscurely ―― a thing for which I really have not time at mydisposal. It was at one time my intention to have reviewed your bookin the same sort of spirit that I did Whewell’s (i.e. pointing out what I
regarded as its defects with the same freedom as it merits) but want of time preventedme. Now I cannot but fancy that it must be useful to an author of a philosophicalwork to know what parts a possible reviewer would have raised objections to.
I remain

Dear Siryours very truly J. F. W. Herschel2

10 July 1845.