The Online Library of Liberty

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• Selections From the Scottish Philosophy of Common Sense
• Introduction
• Thomas Reid
• I.—: Introduction to the Philosophy of Common Sense
• § 1.: The Importance of the Subject, and the Means of Prosecuting It
• § 2.: The Impediments to Our Knowledge of the Mind
• II.—: Analysis of a Typical Sensation
• § 1.: The Sensation Considered Abstractly
• § 2.: Sensation and Remembrance, Natural Principles of Belief
• § 3.: Judgment and Belief In Some Cases Precede Simple Apprehension
• § 4.: Two Theories of the Nature of Belief Refuted—conclusions From What Hath Been Said
• § 5.: Apology For Metaphysical Absurdities—sensation Without a Sentient, a Consequence of the Theory of Ideas—consequences of This Strange Opinion
• § 6.: The Conception and Belief of a Sentient Being Or Mind Is Suggested By Our Constitution—the Notion of Relations Not Always Got By Comparing the Related Ideas
• § 7.: There Is a Quality Or Virtue In Bodies, Which We Call Their Smell—how This Is Connected In the Imagination With the Sensation
• § 8.: That There Is a Principle In Human Nature, From Which the Notion of This, As Well As All Other Natural Virtues Or Causes, Is Derived
• § 9.: Whether In Sensation the Mind Is Active Or Passive?
• III.—: Knowledge and Reality
• § 1.: Of Hardness
• § 2.: Of Natural Signs
• § 3.: Of Extension
• § 4.: Of the Visible Appearances of Objects
• § 5.: Of Perception In General
• § 6.: Of the Process of Nature In Perception
• Appendix: of Cause and Power
• IV.—: The Operations of the Mind
• § 1.: Principles Taken For Granted
• § 2.: Of Hypotheses and Analogy
• § 3.: Of Perception
• § 4.: Of Sensation
• § 5.: Of Primary and Secondary Qualities
• § 6.: Of Conception
• § 7.: Of Judgment
• § 8.: Of Common Sense
• § 9.: The First Principles of Contingent Truths
• § 10.: First Principles of Necessary Truths
• V.—: Of Morals
• § 1.: Of Benevolent Affection In General
• § 2.: There Are Rational Principles of Action In Man
• § 3.: Of Regard to Our Good On the Whole
• § 4.: Of the Notion of Duty, Rectitude, Moral Obligation
• § 5.: Observations Concerning Conscience
• § 6.: That Moral Approbation Implies a Real Judgment
• Adam Ferguson
• Of Man’s Progressive Nature
• James Beattie
• Of the Perception of Truth In General
• Dugald Stewart
• I.—: Of the Object of Philosophy, and the Method of Prosecuting Philosophical Inquiries
• II.—: Of the Association of Ideas
• III.—: Of the Power Which the Mind Has Over the Train of Its Thoughts
• IV.—: Of the Influence of Association On Our Active Principles, and On Our Moral Judgments
• V.—: Of Certain Laws of Belief, Inseparably Connected With the Exercise of Consciousness, Memory, Perception, and Reasoning

§ 1.

Of Hardness

Hardness of bodies is a thing that we conceive as distinctly, and believe as firmly, as anything in nature. We have no way of coming at this conception and belief, but by means of a certain sensation of touch, to which hardness hath not the least similitude; nor can we, by any rules of reasoning, infer the one from the other. The question is, How we come by this conception and belief?

First, as to the conception: Shall we call it an idea of sensation, or of reflection? The last will not be affirmed; and as little can the first, unless we will call that an idea of sensation which hath no resemblance to any sensation. So that the origin of this idea of hardness, one of the most common and most distinct we have, is not to be found in all our systems of the mind: not even in those which have so copiously endeavoured to deduce all our notions from sensation and reflection.

But, secondly, supposing we have got the conception of hardness, how came we by the belief of it? Is it self-evident, from comparing the ideas, that such a sensation could not be felt, unless such a quality of bodies existed? No. Can it be proved by probable or certain arguments? No; it cannot. Have we got this belief, then, by tradition, by education, or by experience? No; it is not got in any of these ways. Shall we then throw off this belief as having no foundation in reason? Alas! it is not in our power; it triumphs over reason, and laughs at all the arguments of a philosopher. Even the author of the Treatise of Human Nature, though he saw no reason for this belief, but many against it, could hardly conquer it in his speculative and solitary moments; at other times, he fairly yielded to it, and confesses that he found himself under a necessity to do so.

What shall we say, then, of this conception, and this belief, which are so unaccountable and untractable? I see nothing left, but to conclude, that, by an original principle of our constitution, a certain sensation of touch both suggests to the mind the conception of hardness, and creates the belief of it: or, in other words, that this sensation is a natural sign of hardness. And this I shall endeavour more fully to explain.