man Nature, to which my attention was, for many years, statedly and forcibly called by my official duty. Much, indeed, still remains to be done in maturing, digesting, and arranging many of the doctrines which I was accustomed to introduce into my lectures; but if I shall be blessed, for a few years longer, with a moderate share of health and of mental vigor, I do not altogether despair of yet contributing something, in the form of Essays, to fill up the outline which the sanguine imagination of youth encouraged me to conceive, before I had duly measured the magnitude of my undertaking with the time or with the abilities which I could devote to the execution.

The volume which I now publish is more particularly intended for the use of Academical Students; and is offered to them as a guide or assistant, at that important stage of their progress when, the usual course of discipline being completed, an inquisitive mind is naturally led to review its past attainments, and to form plans for its future improvement. In the prosecution of this design, I have not aimed at the establishment of new theories; far less have I aspired to the invention of any rew organ for the discovery of truth. My principal object is to aid my readers in unlearning the scholastic errors which, in a greater or less degree, still maintain their ground in our most celebrated seats of learning ; and by subjecting to free, but I trust, not sceptical discussion, the more enlightened though discordant systems of modern Logicians, to accustom the understanding to the unfettered exercise of its native capacities. That several of the views opened in the following pages appear to myself original, and of some importance, I will not deny; but the reception these may meet with I shall regard as a matter of comparative indifferenc my labors be found useful in training the mind to

habits of reflection on its own operations, which may enable it to superadd to the instructions of the schools, that higher education which no schools can bestow.

Kinneil-House, 22d November, 1813.

CONTENTS.

PART SECOND.

OF REASON, OR THE UNDERSTANDING, PROPERLY SO CALLED;

AND THE VARIOUS FACULTIES AND OPERATIONS MORE IMMEDI-

ATELY CONNECTED WITH IT

Page 1

Preliminary Observations on the Vagueness and Ambiguity of

the common Philosophical Language relative to this part of

or Constitution,-Reason and Reasoning,-Understanding,-

Intellect,-Judgment, &c.

CHAPTER I.

Of the Fundamental Laws of Human Belief; or the Primary Ele-

ments of Human Reason.

SECT. I.-Of Mathematical Axioms

1.

2. Continuation of the same Subject

II.—Of certain Laws of Belief, inseparably connected

with the Exercise of Consciousness, Memory, Per-

ception, and Reasoning

III.-Continuation of the Subject.-Critical Remarks on

some late Controversies to which it has given rise.

-Of the Appeals which Dr. Reid and some other

Modern Writers have made, in their Philosophical

Discussions, to Common Sense, as a Criterion of

Truth

18

19

31

35

46

SECT. I.

CHAPTER II.

Of Reasoning and of Deductive Evidence.

1. Doubts with respect to Locke's Distinction be-

tween the Powers of Intuition and of Reasoning

2. Conclusions obtained by a process of Dedu

often mistaken for Intuitive Judgments

b

II. Of General Reasoning

1. Illustrations of some Remarks formerly stated in

treating of Abstraction

2. Continuation of the Subject.-Of Language con-

sidered as an Instrument of Thought

3. Continuation of the Subject.-Visionary Theories

of some Logicians, occasioned by their inattention

to the Essential Distinction between Mathematics

and other Sciences

4. Continuation of the Subject.-Peculiar and super-

eminent Advantages possessed by Mathematicians,

in consequence of their definite Phraseology

III. Of Mathematical Demonstration

75

75

91

97

104

106

1. Of the circumstance on which Demonstrative Evi-

dence essentially depends

2. Continuation of the Subject.-How far it is true

that all Mathematical Evidence is resolvable into

Identical Propositions

3. Continuation of the Subject.-Evidence of the

Mechanical Philosophy, not to be confounded with

that which is properly called Demonstrative or

Mathematical. Opposite Error of some late Wri-

ters

IV. Of our Reasoning concerning Probable or Contin-

gent Truths

1. Narrow Field of Demonstrative Evidence.-Of

Demonstrative Evidence, when combined with that

of Sense, as in Practical Geometry; and with those

of Sense and of Induction, as in the Mechanical

Philosophy.-Remarks on a Fundamental Law of

Belief, involved in all our Reasonings concerning

Contingent Truths

2. Continuation of the Subject. Of that Permanence

or Stability in the Order of Nature, which is pre-

supposed in our Reasonings concerning Contingent

Truths

-

106

117

127

144

144

149

3. Continuation of the Subject.-General Remarks

on the Difference between the Evidence of Experi-

ence, and that of Analogy

4. Continuation of the Subject.-Evidence of Testi-

mony tacitly recognised as a ground of Belief, in

our most certain Conclusions concerning Contin-

gent Truths.-Difference between the logical and

the popular meaning of the word Probability

162

171

CHAPTER III.

Of the Aristotelian Logic.

SECT. I. Of the Demonstrations of the Syllogistic Rules given

by Aristotle and his Commentators

II.—General Reflections on the Aim of the Aristotelian

Logic, and on the Intellectual Habits which the

Study of it has a tendency to form.-That the im-

provement of the power of Reasoning ought to be

regarded as only a Secondary Object in the Culture

of the Understanding

-

III.-In what respects the Study of the Aristotelian Logic

may be useful to Disputants.-A general acquaint-

ance with it justly regarded as an essential accom-

plishment to those who are liberally educated.—

Doubts suggested by some late Writers, concerning

Aristotle's claims to the invention of the Syllogistic

Theory

175

193

207

CHAPTER IV.

Of the Method of Inquiry pointed out in the Experimental or Induc-

tive Logic.

SECT. I.-Mistakes of the Ancients concerning the proper ob-

ject of Philosophy.-Ideas of Bacon on the same

Subject.-Inductive Reasoning.-Analysis and Syn-

thesis. Essential difference between Legitimate

and Hypothetical Theories

220

III. Of the Import of the words Analysis and Synthesis

in the Language of Modern Philosophy

II. Continuation of the Subject.-The Induction of

Aristotle compared with that of Bacon

242

252

252

261

1. Preliminary Observations on the Analysis and Syn-

thesis of the Greek Geometricians

2. Critical Remarks on the vague Use, among Mod-

ern Writers, of the Terms Analysis and Synthesis

IV. The Consideration of the Inductive Logic resumed

1. Additional Remarks on the distinction between

Experience and Analogy. Of the grounds afforded

by the latter for Scientific Inference and Conjecture

2. Use and Abuse of Hypotheses in Philosophical

Inquiries. Difference between Gratuitous Hypoth-

eses, and those which are supported by presump-

tions suggested by Analogy.-Indirect Evidence

which a Hypothesis may derive from its agreement

with the Phenomena. Cautions against extending

some of these Conclusions to the Philosophy of the

Human Mind

--

273

273

287