 Egalitarian ideals reach back to ancient times, but in early modern philosophy the arguments appeared to have more efficacy. Locke, Rousseau, Paine, William Godwin, and Mary Wollstonecraft are just some of the more significant philosophers who left their mark on the modern transition to a more equal society. Diderot was an important voice for the abolition of the slave trade and slavery. Both Hume and Smith argued that wage labor was more efficient than slavery and thus gave economic motivations for the significant end to slavery that came to pass in the nineteenth century.