of language his principal study, as it is the main instrument of thought and communication; and in the proper use of it, consists the chief difference between the strong and the weak mind.

"Scribendi recte sapere est et principium et fons.”

In considering the application of mathematical reasoning to moral and metaphysical subjects, it would be unpardonable to overlook the Philosophical Essay of Laplace, on Probabilities, reviewed by Playfair in the twenty-third volume of the Edinburgh Review. Laplace has touched upon the applicability of the calculus to moral sciences in the following order of topics :-First, the probabilities of testimony; second, the votes and decisions of assemblies; third, the judgements of legal tribunals; fourth, tables of mortality, the mean duration of life, of marriages, and any social relations; fifth, illusions in the estimate of probabilities.

Although many just and some curious and novel observations are made by Laplace under these heads, yet their general effect is

to show the wide difference which exists between those events which, by a strict and clear resemblance, can be classed together and subjected to numerical calculation, and those which are of more complicated character, have a less perfect analogy, differ from each other by many circumstances peculiar to each case,-diversities growing out of the general mental, and moral constitution of man, and which cannot, therefore, be so legitimately classed, nor so successfully brought within the category of number. It is indeed somewhat singular, that Laplace should have placed tables of mortality and the duration of life, and the relative proportion of births, marriages, and deaths, to population,-events of such uníformity of character, and so easily and naturally classed,—in connexion with subjects so wide and general as the nature of testimony, the decisions of popular assemblies and legal tribunals, and the illusions of imagination, subjects which he has touched. but slightly. Statistical calculations ought not indeed to be overlooked by the moralist,

since they furnish that extended view of the phenomena of life and of the moral world, which is essential to the deduction of sound moral rules and principles, and affords great help to the interpretation of the laws and ends of Divine Providence in the administration of the world. Any collection of analogous phenomena in the physical world is of importance in the moral, since such collections lay the foundation of general rules, and supply the exact knowledge which is of the greatest use in the conduct of life. But in collecting analogies we must not overlook differences, and be duly cautious in the application of general maxims, which are apt to mislead as well as to instruct. Playfair has made some just remarks on the vagueness of Laplace's language and views on the subject of testimony; and it is easy to conceive that Laplace's devotedness to the exact sciences may have disposed him to an unreasonable mistrust and disregard of all conclusions of the pure intellect, drawn from the phenomena of history and the moral world. But when Playfair intimates that no

conclusion founded on the application of the calculus to moral probabilities should be allowed to interfere with the truths of religion, he seems to imply that such an interference may be anticipated, and rationally feared, and to forget that, to the philosophic mind, truth in all departments must be ever consistent with itself; that though the atoms of the universe may be weighed and measured, and every seeming accident shall be reduced to order and to rule, the reasons for adoring the Creator, and trusting in him and obeying him, and for loving our neighbour as ourselves, will only be proportionably multiplied.

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It is to me truly interesting to observe Laplace perceiving and recording the importance of that principle of association into which Hartley, followed by Mill, resolves all reasoning. The most fertile of all the principles of psychology," (Laplace, p. 224, of the 8vo. edition of his Essay,)" is that of the association of all things which have had in the sensorium a simultaneous or regularly successive existence; an association whereby

the return of one calls up all the others connected with it; the objects which we have formerly seen awaken the traces of things which in the first view were associated with them. These traces call up in the same manner those of other objects, and so on in succession, so that by means of one thing presented to the mind, we can recal an infinity of others, and rest our attention upon whatever we wish to consider. To this principle the employment of signs and language for recalling sensations and ideas belongs; it accounts for the formation and analysis of complex, abstract, and general ideas, and for reasoning. Many philosophers have well developed this principle, which up to the present time constitutes the real part of metaphysics." "I have endeavoured to show in these papers," says Hartley, at the conclusion of his 99th proposition, "that all reasoning, as well as affection, is the mere result of association."

Some further extracts from Laplace might perhaps be given with interest to the reader, but it does not appear to me that Laplace