phenomena, that wherein ideas succeed one another, the ego or person.  All truths concern relations among ideas.  The tactual idea of solidity accustoms us to project the sensations of the other senses also, to transfer them thither where they are not; hence arise the ideas of our body, of external objects, and of space.  If we perceive several such projected qualities together, we refer them to a substratum—­substance, which we know to exist, although not what it is.  By force we mean the unknown, but indubitably existent, cause of motion.

There are no indifferent mental states; every sensation is accompanied by pleasure or pain.  Joy and pain give the determining law for the operation of our faculties.  The soul dwells longer on agreeable sensations; without interest, ideas would pass away like shadows.  The remembrance of past impressions more agreeable than the present ones is need; from this springs desire (desir) then the emotions of love, hate, hope, fear, and astonishment; finally, the will as an unconditional desire accompanied by the thought of its possible fulfillment.  All inclinations, good and bad alike, spring from self-love.  The predicates “good” and “beautiful” denote the pleasure-giving qualities of things, the former, that which is agreeable to smell and taste (and the passions), the latter, that which pleases sight, hearing, feeling (and the intellect).  Morality is the conformity of our actions to laws, which men have established by convention with mutual obligations.  In this way the good, which at first was the servant of the passions, becomes their lord.

Man’s superiority to the brute depends on the greater perfection of his sense of touch; on the greater variety of his wants and his associations of ideas; on the idea of death, which leads him to seek not merely the avoidance of pain but also self-preservation; and the possession of language.  Without denomination no abstractions, no thought, no handing down of knowledge.  Although all that is mental has its origin, in the last analysis, in simple sensations, its development requires emancipation from the sensuous, and language is the means for freeing ourselves from the pressure of sensations by the generalization and combination of ideas.

A more moderate representative of sensationalism was Charles Bonnet, who later exercised a considerable influence in Germany, especially until Tetens (1720-93; Essay in Psychology, or Considerations on the Operations of the Soul, 1755; Analytical Essay on the Faculties of the Soul, 1760; Philosophical Palingenesis, or Ideas on the Past and the Future of Living Beings, 1769, including a defense of Christianity; Collected Works, 1779).  Sensations, to which he, too, reduces all mental life, are, in his view, reactions of the immaterial soul to sense stimuli, which operate merely as occasional causes.  On the other hand, he emphasizes more strongly than Condillac the dependence