whether they have a real, absolute existence, independently of all perception of them, is another question. Dr. Berkeley first started this doubt, and has endeavoured with great ingenuity to prove that external things have only a relative existence, and that the whole material world exists only as being perceived by some mind. This question, though curious, you will at once see to be of no use or consequence. The existence of external things can be of no consequence, of no effect, with respect to us, but as they are perceived by us. Supposing 10,000 worlds to exist, and to be out of the reach of our perception — they are the same to us as if they did not exist. Frivolous, however, as this question is, I will try to throw a little light upon it. It is assumed by most metaphysical writers, by Mr. Hume particularly, that the mind neither does nor can perceive anything but its own ideas; these ideas being alone present to it, and being the only real and immediate objects of its perception. Upon this position it seems impossible to prove that anything else does really and actually exist but such ideas. The mind, having no perception of anything but its own ideas, can have no knowledge of the actual existence of anything else — of the existence of external objects particularly. With this position I always felt myself dissatisfied; and am now, after reading Dr. Reid, and considering the matter with all the attention in my power, perfectly convinced that the position is not true. When I perceive an object by any of my senses, I perceive the object itself and nothing else; I am not conscious of any intervening idea, any intervening object, between the thing itself perceived, and my perception of it. I see a man, a tree my mind perceives a man, a tree, and nothing else. It perceives them

immediately, directly, without anything intervening, that I am conscious of. It perceives the things themselves, not any ideas of such things. Of this fact I feel the same assurance, as I do of my own existence. In what manner this fact is brought about, in what manner the mind is made to perceive external objects, is utterly inexplicable. We only know that it perceives them through the instrumentality of the organs of sense: yet at the time of per ception we have no consciousness of such instrumentality. But the same difficulty attends the other system, that of perceiving ideas only; and the manner, in which such an infinite variety of ideas is brought before the view of the mind, is equally inexplicable. If then we perceive external objects themselves directly and immediately, and not the ideas of such objects, which appears to me to be the fact, it seems to follow that such perception affords as strong a proof of their existence, or, as D'Alembert somewhere states it, 'supposing the existence of external objects, we could not have a stronger proof of such existence than we actually have.' I shall have, at some other time, a little more to say upon the subject of sensible evidence. If what I have said, be not quite clear to you, pray tell me."

"Febr. 1. I do not like the continuance of your cough. Pray, be as careful as possible to avoid all sudden changes from heat to cold, or from cold to heat. The latter in Dr. Brown's opinion is as bad as the former. I have read his Elements. His theory is ingenious, and of the most seducing simplicity. But our knowledge of the nervous system is so very limited, that it can hardly serve as a basis for anything beyond conjecture. The theory, however, has certainly more plausibility, than any that has preceded it. His assertions are positive and strong,

with respect to his success in curing diseases, upon the ground of his theory. But his facts are few indeed. You have not read the book, and therefore I cannot speak to you intelligibly upon it. Parr is passionately fond of Dr. Brown's book, and was so of the man.* I collected here, by his request, 39 guineas and a half for his widow and

*[The book entitled Elementa Medicina, was first published at Edinburgh in 1780. 8vo., republished and enlarged, 1787. 2 vols. 8vo. 1794. 8vo. translated by the Author 1788. 2 vols. 8vo. The Translation was revised and corrected by Dr. Beddoes, with a Biographical Preface, Lond. 1795. 2 vols. 8vo. Dr. William Cullen Brown published the Medical Works of Dr. John Brown, with a Biographical Account of the Author, Lond. 1804. 3 vols. 8vo. Dr. John Brown also wrote a work entitled Observations on the Principles of the Old System of Physic, exhibiting a Compound of the New Doctrine; containing a New Account of the State of Medicine, from the present Times backward to the Restoration of the genuine Learning in the Western Parts of Europe. Edinb. 1787. 8vo. His system is thus concisely and satisfactorily explained in Chalmers's Biographical Dictionary : — "His intention seems to have been to simplify medicine, and to render the knowledge of it easily attainable, without the labour of studying other authors. All general or universal diseases were therefore reduced by him to two great families or classes, the sthenic and the asthenic ;. the former depending upon excess, the latter upon deficiency of exciting power. The former were to be removed by debilitating, the latter by stimulant medicines, of which the most valuable and powerful are wine, brandy, and opium. As asthenic diseases are more numerous, and occur much more frequently than those from an opposite cause, his opportunities of calling in the aid of these powerful stimuli were proportionately nuSpasmodic and convulsive disorders, and even

merous.

6

family. I know not where Drake saw my case in it: I have read it through, and find nothing like it. I have Parr's print, and think it very like him. Twining is not quite satisfied with it, and thinks it wants spirit. I think there is sufficient expression, taking him in his calm moments.*

"You will, if you can, dispose of the inclosed copies

hemorrhages,' he says, 'were found to proceed from debility; and wine and brandy, which had been thought hurtful in these diseases, he found the most powerful of all remedies in removing them.'" Dr. John Brown presented to Dr. Parr his Translation of the Elements of Medicine, and in the Bibl. Parr. 464, Dr. Parr says: "The Gift of the most extraordinary author." Dr. J. B. had presented to Dr. Parr the Latin work at the time of its publication, with the following inscription:

"Reverendo Viro, d Musis præ reliquis alto, et in intimo Pierii antri recessu nutrito, Samueli Parrio, cœptam literis consuetudinem, præsentia firmatam, et amicitia munitam, cupiens, exagitate a Medicis doctrinæ exemplum, JOANNES BRUNO, male mactatus auctor."

A young medical student from Edinburgh was introduced to Buonaparte, who generally adapted his conversation to the pursuits of those, who frequented his court. After the ceremony of introduction, Buonaparte asked the youth some questions about the Brunonian system; the youth, from ignorance or bashfulness, was silent; the Emperor, with great condescension and much address, at once relieved him from his embarassment by saying You are, I see, the follower of no system, but a student of nature.' E. H. B.]

* [The print in question is, I suppose the one taken from the portrait by Opie, which was painted for T. W. Coke, Esq. M. P., and enriches the noble collection at Holkham. E. H. B.]

of Charles Shillito's Poem.* I send you also Twining's book: it will be published, I imagine, in the course of this week. Do not shew it to any one till it is published.

"The 47th 1 Euclid is indeed a beautiful proposition. Endeavour to carry it back in your mind, through all the propositions, upon which it depends, to its first principles.

"You will burst into a laugh, when you come to Socrates's demonstration of the præ-existence of the human mind. The demonstration is short: All knowledge is reminiscence; but reminiscence supposes præ-existence; ergo' etc. Of Plato's famous doctrine of ideas, we shall have a little talk hereafter. Duncan is undoubtedly wrong: the first impressions, which the mind receives, are certainly from sensible objects.

"Your remarks upon Berkeley's theory are quite as good as those of Beattie, Campbell, and many others, who have attempted to answer him; but they do not reach the point. Berkeley does not mean to prove that external objects have not absolute existence, but only that there is no proof that they have.† And upon the commonly received

*[See Dr. Watt's Bibliotheca Britannica. He was a Lieutenant in the Marines. E. H. B.]

+ [Johnson described Berkeley as "a profound scholar, as well as a man of fine imagination," Boswell's Life of Johnson 2, 131.—“Being in company with a gentleman, who thought fit to maintain Dr. Berkeley's ingenious philosophy, that nothing exists but as perceived by some mind, when the gentleman was going away, Johnson said to him, 'Pray, Sir, do not 'leave us; for we may perhaps forget to think of you, and then 'you will cease to exist.' 4, 27. "After we came out of the church," says Boswell 1, 437. we stood talking for some time together of Bishop Berkeley's ingenious sophistry to prove the