John Locke Essay Concerning Human Understanding Online
One of Locke's fundamental arguments against innate ideas is the very fact that there is no truth to which all people attest.He took the time to argue against a number of propositions that rationalists offer as universally accepted truth, for instance the principle of identity, pointing out that at the very least children and idiots are often unaware of these propositions.He describes the mind at birth as a blank slate (tabula rasa, although he did not use those actual words) filled later through experience.The essay was one of the principal sources of empiricism in modern philosophy, and influenced many enlightenment philosophers, such as David Hume and George Berkeley.Locke writes at the beginning of the fourth chapter, Of the Reality of Knowledge): "I doubt not my Reader by this Time may be apt to think that I have been all this while only building a Castle in the Air; and be ready to say to me, To what purpose all of this stir?Knowledge, say you, is only the Perception of the Agreement or Disagreement of our own Ideas: but who knows what those Ideas may be? But of what use is all this fine Knowledge of Man's own Imaginations, to a Man that enquires after the reality of things?Book III is concerned with language, and Book IV with knowledge, including intuition, mathematics, moral philosophy, natural philosophy ("science"), faith, and opinion.Book I of the Essay is devoted to an attack on nativism or the doctrine of innate ideas; Locke indeed sought to rebut a prevalent view, of innate ideas, that was vehemently held by philosophers of his time.
In Book II, Locke focuses on the ideas of “substances” and “qualities”, in which substances are “an unknown support of qualities” and qualities have the “power to produce ideas in our mind”.Leibniz thought that Locke's commitment to ideas of reflection in the Essay ultimately made him incapable of escaping the nativist position or being consistent in his empiricist doctrines of the mind's passivity.The empiricist George Berkeley was equally critical of Locke's views in the Essay.He also criticizes the use of words which are not linked to clear ideas, and to those who change the criteria or meaning underlying a term.Thus he uses a discussion of language to demonstrate sloppy thinking.
Locke followed the Port-Royal Logique (1662) in numbering among the abuses of language those that he calls "affected obscurity" in chapter 10.