The Quest for Knowledge and Certainty

1. The Quest for Knowledge and Certainty Discourse on Epistemology

2. Descartes • Descartes began his philosophy by sweeping away all the “errors of the past” by forming a radical form of skepticism about what we take for granted as knowledge and certainty. • Instead of fighting doubt, he would use it to find certainty. “He would use doubt as an acid to pour over every “truth” that could not be doubted. • The key was to find knowledge that he could “clearly and evidently intuit” that could serve as his starting point.

3. Descartes • After subjecting all his knowledge to the acid of doubt, he concluded that there was one thing he could not doubt: that he was doubting. • The one fact the acid of doubt could not dissolve was doubt itself. • This meant there had to be an “I” who was doing the doubting.

4. Descartes • Even if he were deceived about everything else, he had to exist in order to be deceived. • This led Descartes to his famous statement, Cogito ergo sum, meaning “I think, therefore I am” (In more accurate translations, this statement actually amounts to saying that “I am a thinking thing” or “this thinking thing called the I”).

5. Descartes • In subsequent Meditations, Descartes relies on the innate ideas with which he claims the mind is furnished. • A priori: A belief, proposition, or argument is said to be a priori if its truth or falsity can be established independently of observation. Definitions, the propositions of arithmetic, and the principles of logic are usually held to be a priori. • Innate ideas: An idea present at birth, hence, a priori.

6. Rationalism • The epistemological view that true knowledge is derived primarily from reason (or exclusively from reason in the purer strains of rationalism). Reason is conceived as the working of the mind on material provided by the mind itself. In most versions, this material take the form of innate ideas. Therefore, for the rationalists, a priori knowledge is the most important kind of knowledge.

7. The Senses as the Basis of Knowledge: John Locke, Essay concerning Human Understanding • John Locke launched a massive broadside against the doctrine of innateness, arguing instead that the senses are the primary source of all knowledge. • He compares the mind to a tabula rasa, a blank slate or ‘white paper devoid of all characters’, and then asks ‘whence has it all the materials of reason and knowledge?’.

8. John Locke (29 August 1632- 28 October 1704)

9. Human Understanding • “It is an established opinion amongst some men, that there are in the understanding certain innate principles; some primary notions … characters, as it were stamped upon the mind of man, which the soul receives in its very first being; and bring into the world with it.” Locke, Pp. 26.

10. Human Understanding • “It would be sufficient to convince unprejudiced readers of the falseness of this supposition, if I should only show … how men, barely by the use of their natural faculties, may attain to all the knowledge they have, without the help of any innate impressions; and may arrive at certainty, without any such original notions or principles.” Locke, Pp. 26.

11. Human Understanding • “This argument, drawn from universal consent, has this misfortune in it: that if it were true in matter of fact, that there were certain truths wherein all mankind agreed, it would not prove them innate, if there can be any other way shown how men may come to that universal agreement in the things they do consent in; which I presume may be done.” Locke, Pp. 27.

12. Human Understanding • Locke argues that the reasoning traditionally employed to support the doctrine of innate ideas is wholly inadequate. • Locke is here appealing to a principle that would become dear to empiricism, what is known as Ockham’s Razor. • Ockham’s Razor: A principle of simplification, according to which if there are two competing theories, both of which account for all the observable data, the simpler of the two is the preferable theory. “Do not multiply entities beyond necessity.”

13. Human Understanding

14. Human Understanding • Locke hopes to provide a simpler answer to the questions of knowledge and certainty found in human understanding. • Locke wanted a theory in which only particulars exist would be simpler than one in which there existed particulars and abstractions.

15. Human Understanding • Universal assent cannot be made: “But, which is worse, this argument of universal consent, which is made use of to prove innate principles, seems to me a demonstration that there are none such: because there are none to which all mankind give a universal assent. • Even the principle on non-contradiction – “are so far from having a universal assent that there are a great part of mankind to whom they are not so much as known.” Locke, Pp. 27.

16. Human Understanding • Locke cites the cases of ‘idiots and children’: “For, first it is evident that all children, and idiots, have not the least apprehension or thought of them: and the want of that is enough to destroy that universal assent, which must need be the necessary concomitant of all innate truths: it seeming to me near a contradiction to say that there are truths imprinted on the soul which it perceives or understands not; imprinting, if it signify any thing, being nothing else but the making certain truths to be perceived.” Locke, Pp. 27.

17. Human Understanding

18. Human Understanding • “To say a notion is imprinted on the mind, and yet at the same time to say that the mind is ignorant of it, and never yet took notice of it, is to make this impression nothing.” Locke, Pp. 27. • “[If these universal propositions] are by nature imprinted, children cannot be ignorant of them: infants, and all that have souls must necessarily have them in their understandings, know the truth of them, and assent to it.” Locke, Pp. 28.

19. Human Understanding • Locke’s response to reason: “If they mean that by the use of reason men may discover these principles, and that this is sufficient to prove them innate, their way of arguing will stand thus: that whatever truths reason can certainly discover to us, and make us firmly assent to, those are all naturally imprinted on the mind; since that universal assent, which is made the mark of them amounts to no more but this – that by the use of reason, we are capable to come to a certain knowledge of, and assent to them.” Locke, Pp. 28.

20. Human Understanding • “First, it is false. Because it is evident these maxims are not in the mind so early as the use of reason; and therefore the coming to the use of reason is falsely assigned as the time of their discovery… A great par of illiterate people, and savages, pass many years even of their rational age, without ever thinking on this, and the like general propositions.” Locke, Pp. 29.

21. Human Understanding • Coming to the use of reason does not prove these discoveries innate – which the rationalists wanted to show. • Locke sees the use of reason as simply the making of general abstract ideas and the understanding of general names. • Locke then proceeds to set out his own account of how we come to knowledge of general propositions: the senses first ‘let in particular ideas’, and furnish the ‘yet empty cabinet’ (the image here is of the mind as a chamber that is entirely empty until the data from the senses enter it); the mind then gets to work on these materials, abstracting from the particular and learning the use of ‘general names’.

22. Human Understanding • Simple and Complex Ideas: Simple ideas are those that cannot be further analyzed into simpler components, for example, the idea of “solidity” or the idea of “yellow”. • These ideas usually come in through one sense, though some of them, such as the idea of “motion,” can be derived either from the sense of touch or the sense of sight.

23. Human Understanding • Simple and Complex Ideas: Complex ideas are (1) compounds of simple ideas (e.g., “beauty,” “gratitude,” “a man,” “an army,” “the universe”), (2) ideas of relations (larger than, smaller than) created by setting two ideas next to each other and comparing or contrasting them, or (3) abstractions, wherein the mind separates out a feature of an idea and generalizes it ( e.g., blueness).

24. Human Understanding • Simple and Complex Ideas: Abstractions are formed when we recognize a certain characteristic that a group of objects has in common. • That characteristic is assigned a name, which is a symbol for the characteristic. • Locke’s view is that the rationalists has confused these “abstract general ideas” with actual existing entities (Platonic Forms) or with innate ideas.

25. Human Understanding • Locke does not deny that human beings have innate capacities, but he argues that a capacity to come to know X is not at all the same as innate knowledge of X. • If it were, then one would have to say, absurdly, that we have innate knowledge of everything we learn in life. • His uncompromising conclusion is that the human mind does not have the least glimmering of an ideas which it does not receive either from sensation or subsequent reflection.

26. Human Understanding • “Let us suppose the mind to be, was we say, white paper, void of all characters, without any ideas…Our observations employed either about external sensible objects, or about the internal operations of our minds perceived and reflected on by ourselves, is that which supplies our understandings with all the materials of thinking.” Locke, Pp. 30.

27. Human Understanding

28. Human Understanding • What are Locke’s main arguments against the doctrine of innate knowledge? Do you find them compelling?

29. Innate Knowledge Defended: Gottfried Leibniz, New Essays On Human Understanding • Leibniz agrees with Locke that sensory stimulation is necessary for the acquisition of knowledge. • But he argues that it is not, by itself, sufficient. • The senses merely elicit or activate what is already in a certain sense present within us – ‘living fires or flashes of light hidden inside us but made visible by stimulation of the senses, as sparks can be struck from a steel’.

30. Gottfried Wilhelm Leibniz (1 July 1646 – 14 November 1716)

31. New Understanding • Leibniz goes on to cite the necessary truths of mathematics as support for his version of the theory of innateness: the truth of such propositions ‘does not depend on instances, nor consequently on the testimony of the senses’. • “His ideas are closer to Aristotle and mine to Plato, although each of us parts company at many points from the teaching of both of these ancient writers.” Leibniz, Pp. 32.

32. New Understanding • “There is the question whether the soul in itself is completely blank like a writing tablet on which nothing has yet been written – a tabula rasa – as Aristotle and the author of the Essay maintain, and whether everything which is inscribed there comes solely from the senses and experience; or whether the soul inherently contains the sources of various notions and doctrines, which external objects merely rouse up on suitable occasions, as I believe and as do Plato … and all those who understand in this sense the passage in St Paul where he says that god’s law is written in our hearts (Romans, 2:15).”

33. New Understanding • From this it appears that necessary truths, such as we find in pure mathematics and particularly in arithmetic and geometry, must have principles whose proof does not depend on instances nor, consequently, on the testimony of the senses, even though without the senses it would never occur to us to think of them.” Leibniz, Pp. 33.

34. New Understanding

35. New Understanding • “I have also used the analogy of a veined block of marble, as opposed to an entirely homogeneous block of marble, or to a blank tablet – what the philosophers call a tabula rasa…[I]f there were veins in the block which marked out the shape of Hercules rather than other shapes, then that block would be more determined to that shape and Hercules would be innate in it, in a way, even though labor would be required to expose the veins and to polish them into clarity, removing everything that prevents their being seen.” Leibniz, Pp. 34.

36. New Understanding

37. New Understanding • “Our gifted author seems to claim that there is nothing potential in us, in fact nothing of which we are not always actually aware.” Leibniz, Pp. 35.

38. New Understanding • Why does Leibniz believe that knowledge of the principles of logic and mathematics cannot be derived from experience?

39. Homework • 1) Skepticism versus Human Nature – David Hume, Enquiry concerning Human Understanding: Pp. 35-39. • 2) Experience and Understanding – Immanuel Kant, Critique of Pure Reason: Pp. 40-43. • 3) The Conditions for Knowledge – Edmund Gettier, Is Justified True Belief Knowledge?: Pp. 60-63.