Now, after having considered the state of Medicine under the Asclepiadae, in the isle of Cos, in an exclusively practical manner, and, in some sort, material also, it remains for us to examine it in a theoretical point of view to seek the invisible bond that unites all parts of their doctrines, and connects them to a common principle, as the branches of the same tree.
In all times, and perhaps in ours more than any other, systems have been decried. They have been and are still accused of being only a tissue of errors and a source of eternal discussion. The epithet systematic, (theoretic - with us. 7V.) applied to an author or a book, has become an expression of disdain. Many would banish from Medicine all theory, all system, and preserve only the facts and results of experience. Their plan appears very commodious and sure, at first sight, but when more closely examined, it is impracticable. Those who have recommended it the most, have not been able to avoid violating the plan, in their writings as well as in their practice. M. Bouillaud (Essai de Philos. Médicale. Paris, 1837, deuxieme partie, chap, in, art. 1, Â§ 1) demonstrates this in a positive manner ; and M. Monfalcon, but little favorable to systematic writers, is also forced to say : " Much has been said against systems and certainly with truth. We condemn them and still we are not able to do without them. Every instructed physician has a way of explaining to himself life and diseases ; he wishes to form an opinion of what he sees as well as of what he docs. If the received doctrines do not satisfy him, he modifies them, in a way most satisfactory to himself.(Diction, des Sciences Me'dicales, the words System and Théorie)
I will add, that learned physicians are not the only ones that essay to interpret the phenomena of life ; for in this respect the most ignorant are no less prodigal in explanations, nor less prepossessed in their manner of regarding them ; so natural and irresistible is the impulse to try to explain the phenomena that strike our senses.
In fact I may say, without a theory, without some systematic arrangement of partial opinions that tend toward a common end, there exists no science. Clinical observations, collected with care, but arranged without art and method, in a word, without system, constitute no more a scientific edifice, than a confused pile of materials constitutes a monument of architecture.
Theories and systems concur to the advancement of the sciences by uniting by an artificial bond the diverse notions of which they are composed,
in a way to assist the memory, and enlighten the judgment. It is true that scientific systems sometimes propagate illusions and ridiculous prejudices, but the illusions and prejudices that spring from ignorance and barbarism, that is to say, from the absence of all reasonable system, are no less numerous, ridiculous, and absurd.
A system is true, when it is founded on real analogies ; it is false, when it rests on imaginary analogies. A system may be true in certain parts, and false in others ; but there are few systems that are entirely erroneous. This is also the opinion of the writer that I have just cited. " If systems," says M. Monfalcon, " were composed only of errors, of conjectural opinions, they would make but few partisans ; but there is not one that does not repose on some important fact or some well recognized physiological law. Those who propose them do no other wrong than exagerate these laws and make the whole of Medicine subordinate to them : those who adopt them see only one side of the subject, and submit too blindly to the reason of one single man.(Diction, des Scienc. Medic, the word System)
Thus then the most common defect of medical systems is not a lack of foundation, nor the want of a support derived from correct observation, but it is rather the exageration of certain truths, to the neglect of others not less important - the consideration of objects too exclusively under one aspect. " The fault," says Bichat, " with those who have a general idea on Medicine, is to bend all the phenomena to this idea. The defect of generalizing too much has perhaps been more injurious to science, than that of seeing each phenomenon in an isolated manner. (Anat. Gen., Considerat. Gen., p. 13)
Being convinced of the necessity of theories to harmonize the various ramifications of science, persuaded that without their aid the human understanding could not grasp a great extent of knowledge, nor elevate itself to the highest considerations, we shall accord to this important branch of Medicine all the attention that it merits, without forgetting that it offers only an ideal and an imperfect image of phenomena, and that it can not in any case replace the study of real nature, or take the place of direct observation.
From History of Medicine by P.V. Renouard M.D.