and chemical fubjects which are daily offered to the public, whether it be yet understood fo completely as is commonly imagined; and whether a fuller illuftration of the rules of philofophifing, than Bacon or his followers have given, might not be useful, even to phyfical inquirers.

When we reflect, in this manner, on the fhortness of the period during which natural philosophy has been fuccefsfully cultivated; and, at the fame time, confider how open to our examination the laws of matter are, in comparison of thofe which regulate the phenomena of thought, we fhall neither be difpofed to wonder, that the philofophy of mind fhould ftill remain in its infancy, nor be difcouraged in our hopes concerning its future progrefs. The excellent models of this fpecies of investigation, which the writings of Dr. Reid exhibit, give us ground to expect that the time is not far diftant, when it fhall affume that rank which it is entitled to hold among the sciences.

It would probably contribute much to accelerate the progrefs of the philofophy of mind, if a diftin& explanation were given of its nature and object; and if fome general rules were laid down, with refpect to the proper method of conducting the study of it. To this fubject, however, which is of fufficient extent to furnish matter for a feparate work, I cannot attempt to do justice at prefent; and fhall therefore confine myself to the illustration of a few fundamental princi-ples, which it will be of effential importance for us to keep in view in the following inquiries.

Upon a flight attention to the operations of our own minds, they appear to be fo complicated, and fo infinitely diverfified,

diverfified, that it feems to be impoffible to reduce them to any general laws. In confequence, however, of a more accurate examination, the profpect clears up; and the phenomena, which appeared, at firft, to be too various for our comprehenfion, are found to be the refult of a comparatively fmall number of fimple and uncompounded faculties, or of fimple and uncompounded principles of action. Thefe faculties and principles are the general laws of our conftitution, and hold the fame place in the philofophy of mind, that the general laws we investigate in phyfics, hold in that branch of fcience. In both cafes, the laws which nature has established, are to be investigated only by an examination of facts; and in both cases, a knowledge of thefe laws leads to an explanation of an infinite number of phenomena.

In the investigation of physical laws, it is well known, that our inquiries must always terminate in fome general fact, of which no account can be given, but that fuch is the conftitution of nature. After we have established, for example, from the aftronomical phenomena, the univerfality of the law of gravitation, it may still be asked, whether this law implies the conftant agency of mind; and (upon the fuppofition that it does) whether it be probable that the Deity always operates immediately, or by means of fubordinate inftruments? But thefe queftions, however curious, do not fall under the province of the natural philofopher. It is fufficient for his purpose, if the univerfality of the fact be admitted.

The cafe is exactly the fame in the philofophy of mind. When we have once afcertained a general

fact;

fact; fuch as, the various laws which regulate the affociation of ideas, or the dependence of memory on that effort of the mind which we call, Attention; it is all we ought to aim at, in this branch of science. If we proceed no farther than facts for which we have the evidence of our own conscioufnefs, our conclufions will be no lefs certain, than thofe in phyfics: but if cur curiofity leads us to attempt an explanation of the affociation of ideas, by certain fuppofed vibrations, or other changes, in the ftate of the brain; or to explain memory, by means of fuppofed impreffions and traces in the fenforium; we evidently blend a collection of important and well-afcertained truths, with principles which reft wholly on conjecture*,

The

There is indeed one view of the connexion between Mind and Matter, which is perfectly agreeable to the just rules of philosophy. The object of this is, to afcertain the laws which regulate their union, without attempting to explain in what manner they are -united.

Lord Bacon was, I believe, the first who gave a distinct idea of this fort of fpeculation; and I do not know that much progrefs has yet been made in it. In his books de Augmentis Scientiarum, a variety of subjects are enumerated, in order to illuftrate its nature; and, undoubtedly, moft of thefe are in a high degree curious and important. The following lift comprehends the chief of those he has mentioned; with the addition of feveral others, recommended to the confideration of Philofophers and of Medical Inquirers, by the late Dr. Gregory. See his Lectures on the Dutics and Qualifications of a Physician.

1. The doctrine of the prefervation and improvement of the different fenfes.

2. The history of the power and influence of imagination. 3. The history of the several species of enthufiafm.

4. The history of the various circumstances in parents, that have

The obfervations which have been now ftated, with refpect to the proper limits of philofophical curiosity, have too frequently escaped the attention of fpeculative men, in all the different departments of science. In none of these, however, has this inattention produced fuch a variety of errors and abfurdities, as in the science of mind; a subject to which, till of late, it does not seem to have been fufpected, that the general rules of philofophifing are applicable. The ftrange mixture of fact and hypothefis, which the greater part of me taphyfical inquiries exhibit, had led almoft univerfally

an influence on conception, and the conftitution and characters of their children.

5. The hiftory of dreams.

6. The hiftory of the laws of cuftom and habit.

7. The hiftory of the effects of mufic, and of fuch other things. as operate on the mind and body, in confequence of impreffions made on the fenfes.

8. The hiftory of natural figns and language, comprehending the doctrine of phyfiognomy and of outward gesture.

9. The hiftory of the power and laws of the principle of imi

tation.

To this lift various other fubjects might be added; particularly, the hiftory of the laws of memory, in fo far as they appear to be connected with the ftate of the body; and the hiftory of the different fpecies of madnefs.

This view of the connection between Mind and Matter does not fall properly under the plan of the following work; in which my leading object is to afcertain the principles of our nature, in fo far as they can be discovered by attention to the subjects of our own confcioufnefs; and to apply thefe principles to explain the phenomena arifing from them. Various incidental remarks, however, will occur in the course of our inquiries, tending to illustrate Lome of the fubjects comprehended in the foregoing enumeration.

to

to a belief, that it is only a very faint and doubtful light, which human reafon can ever expect to throw on this dark, but interesting, field of fpeculation.

Befide this inattention to the proper limits of philofophical inquiry, other fources of error, from which the fcience of phyfics is entirely exempted, have contributed to retard the progrefs of the philofophy of mind. Of thefe, the most important proceed from that difpofition which is fo natural to every person at the commencement of his philofophical purfuits, to explain intellectual and moral phenomena by the analogy of the material world.

I before took notice of thofe habits of inattention to the fubjects of our consciousness, which take their rife in that period of our lives when we are neceffarily employed in acquiring a knowledge of the properties and laws of matter. In confequence of this early familiarity with the phenomena of the material world, they appear to us lefs myfterious than those of mind; and we are apt to think that we have advanced one step in explaining the latter, when we can point out fome analogy between them and the former. It is owing to the fame circumftance, that we have scarcely any appropriated language with refpect to mind, and that the words which express its different operations, are almost all borrowed from the objects of our fenfes. It muft, however, appear manifeft, upon a very little reflection, that as the two fubjects are effentially diftinct, and as each of them has its peculiar laws, the analogies we are pleased to fancy between them, can be of no use in illuftrating either; and that it is no lefs unphilofo