Science can never be retrograde

This is from my letter to William G. Munford, June 18, 1799:

I am among those who think well of the human character generally. I consider man as formed for society, and endowed by nature with those dispositions which fit him for society. I believe also that his mind is perfectible to a degree of which we cannot as yet form any conception. It is impossible for a man who takes a survey of what is already known, not to see what an immensity in every branch of science yet remains to be discovered, & that too of articles to which our faculties seem adequate.

In geometry & calculation we know a great deal, yet there are some desiderata. In anatomy great progress has been made; but much is still to be acquired. In natural history we possess knowlege; but we want a great deal. In chemistry we are not yet sure of the first elements. Our natural philosophy is in a very infantine state; perhaps for great advances in it, a further progress in chemistry is necessary. Surgery is well-advanced; but prodigiously short of what may be.

The state of medicine is worse than that of total ignorance. Could we divest ourselves of every thing we suppose we know in it, we should start from a higher ground & with fairer prospects. From Hippocrates to Brown we have had nothing but a succession of hypothetical systems each having it’s day of vogue, like the fashions & fancies of caps & gowns, & yielding in turn to the next caprice. Yet the human frame, which is to be the subject of suffering & torture under these learned modes, does not change. We have a few medicines, as the bark, opium, mercury, which in a few well defined diseases are of unquestionable virtue: but the residuary list of the materia medica, long as it is, contains but the charlataneries of the art; and of the diseases of doubtful form, physicians have ever had a false knowledge, worse than ignorance. Yet surely the list of unequivocal diseases & remedies is capable of enlargement; and it is still more certain that in the other branches of science, great fields are yet to be explored to which our faculties are equal, & that to an extent of which we cannot fix the limits.

I join you therefore in branding as cowardly the idea that the human mind is incapable of further advances. This is precisely the doctrine which the present despots of the earth are inculcating, & their friends here re-echoing; & applying especially to religion & politics; ‘that it is not probable that any thing better will be discovered than what was known to our fathers.’ We are to look backwards then & not forwards for the improvement of science, & to find it amidst feudal barbarisms and the fires of Spital-fields.

But thank heaven the American mind is already too much opened, to listen to these impostures; and while the art of printing is left to us science can never be retrograde; what is once acquired of real knowledge can never be lost. To preserve the freedom of the human mind then & freedom of the press, every spirit should be ready to devote itself to martyrdom; for as long as we may think as we will, & speak as we think, the condition of man will proceed in improvement. The generation which is going off the stage has deserved well of mankind for the struggles it has made, & for having arrested that course of despotism which had overwhelmed the world for thousands & thousands of years. If there seems to be danger that the ground they have gained will be lost again, that danger comes from the generation your contemporary. But that the enthusiasm which characterises youth should lift it’s parracide hands against freedom & science, would be such a monstrous phaenomenon as I cannot place among possible things in this age & this country.