Conscience is the voice of the soul, the passions are the voice of the body. Is it astonishing that often these two languages contradict each other, and then to which must we listen? Too often reason deceives us; we have only too much acquired the right of refusing to listen to it; but conscience never deceives us; it is the true guide of man; it is to man what instinct is to the body; which follows it, obeys nature, and never is afraid of going astray.
Jean-Jacques RousseauEverything is in constant flux on this earth. Nothing keeps the same unchanging shape, and our affections, being attached to things outside us, necessarily change and pass away as they do. Always out ahead of us or lagging behind, they recall a past which is gone or anticipate a future which may never come into being; there is nothing solid there for the heart to attach itself to. Thus our earthly joys are almost without exception the creatures of a moment.
Jean-Jacques Rousseau