My dear Mr Darwin

Many thanks for your note; and for calling my attention to M. Houzeau’s volumes, which I will certainly look into before attempting anything in their line myself.¹ It must be a great advantage, particularly on such a subject as the mental powers and habits of animals to have gained the habits of independent observation which the position of the conscientious travelling naturalist tends to produce; who must stand for the first respectable authority on the matters of his observations.² Most of the books I have seen on the psychical side of natural history are with reference to the requirements of science so like semi-fabuous, or even mythical histories, (whose motive is to tell a good story,—the more surprising, within limits, the better;—) and their matters consist so obviously of selected cases, chosen a priori with reference to theoretical bearings, authenticity, or the probability of their accuracy, that they seem to me to be almost wholly worthless;—theoretical considerations are so inextricably mixed up with simple (or the soundest, most cautious) observation in such matters.

But to make even the testimony of a conscientious travelling naturalist of much value (with reference to the requirements of mental science) he should be an equally able, independent and conscientious or accurate explorer in the microcosm; and as free from traditional and refutable reports about this world as he is of unauthentic or doubtful ones in the other. Preconceptions of the difference in the powers of the lower animals and those of men, founded solely on metaphysical theories of the latter, seem to me quite as likely to be misleading as the testimony of ignorant or inexpert witnesses about facts for which the traveller has to assume responsibility. At present I am inclined to the belief that the actions of domestic animals,—those even the most familiar to the actual observers of them,—would alone be quite sufficient to disprove, if rightly interpreted, the existence of impassable barriers, (credited on the report of metaphysical explorers,) which are supposed to separate the causes of similar actions in men and other animals; or to separate them more widely than mental powers are between any other parts of the animal series. No doubt the gulf seems formidable from a self-conscious, merely human point of view. But this pinnacle may be easily accessible from the lowest valley in a direction different from that on which the metaphysician fixes his amazed attention. I hope, therefore, that the book will be found to have undertaken the scientific definition of proper instincts as distinguished on one hand from simpler modes of action both in animals and plants, and on the other hand from the more complex ones of the higher animals.; and to have attempted the resolution of various metaphysical simples, such as reminiscence or voluntary acts of memory; abstraction, especially the supersensible sort; free or intelligent volitions, and self-consciousness; and more than all to determine what should be meant by that very vague and ambiguous word “reason”, when considered in contrast to instinct. If reason and self-consciousness are taken from the naturalist’s point of view to be the simple natures they are usually supposed to be, and instinct to be from the same point of view an elaborate mental device, serving as a substitute for them, then very little progress will, I believe, be made beyond the mere namings, assumptions and verbal definitions of which the prevalent philosophy of the subject appears to me to consist for the most part.

I am convinced, and hope some day to make out more fully and clearly than has yet, so far as I know, been done, that the most important distinctions of man from animals next him in intelligence are referable through universal laws in mental and in external natures to the comparative vividness of his simplest inartificial memories and the correspondingly greater power he has of governing his perceptions, imaginations, associations and volitions from within, or with reference to his total and individual or personal experiences, and independently of external stimuli, and the organized and inherited effects of these in determining his actions. (Quantam memoriam, tantum ingenium.)³

I look back, My dear Sir, upon my little visit to you with very great satisfaction, and it will always be a bright and memorable incident of my trip in Europe. I have deferred my journey to Paris for a day and a half from being slightly under the weather and indisposed for so long a journey.⁴

Yours very sincerely | Chauncey Wright