This great increase of the quantity of work which, in consequence of the division of labour, the same number of people are capable of performing, is owing to three different circumstances; first, to the increase of dexterity in every particular workman; secondly, to the saving of the time which is commonly lost in passing from one species of work to another; and lastly, to the invention of a great number of machines which facilitate and abridge labour, and enable one man to do the work of many.
Adam SmithThough our brother is upon the rack, as long as we ourselves are at ease, our senses will never inform us of what he suffers. They never did and never can carry us beyond our own persons, and it is by the imagination only that we form any conception of what are his sensations...His agonies, when they are thus brought home to ourselves, when we have this adopted and made them our own, begin at last to affect us, and we then tremble and shudder at the thought of what he feels.
Adam Smith