플라톤 - 테아이테토스 [Plato - Theaetetus]

<Theaetetus>

 

<정리>

 

인식론(epistemology)은 철학의 제 분야 중에서도 특히 나의 흥미를 끄는 부분이다. 그래서 일 년 반 쯤 전에 박이문의 [철학이란 무엇인가]를 읽고 ‘존재와 인식’이라는 글을 써보기도 했다. 플라톤의 후기 저작을 대표하는 글 중 하나인 이 [테아에테토스]는 이 인식론을 (콘포드의 말을 빌자면, How can I know that I know? How can I recognise knowledge when I have it and be sure that it is knowledge?(140)) 심도 있게 다룬 것으로, 콘포드의 원문 및 해설판으로 흥미롭게 읽었다. (나의 영어 능력, 지적 능력, 공들임, 이 모든 것이 시험대에 올라갔고, 내가 할 수 있는 말은 좀더 노력하겠다는 것이었다. 또 체계적으로 이 글을 정리하기 위해서는 다시 읽고, 머리를 쥐어짜야겠지만, 그 작업은 후일로 미루고 개략적으로 머리 속에 남은 인상을 정리하도록 할 것이다.)

인식론은 다시 한 번 이야기 하자면, ‘안다는 것’에 대한 공구인데, 플라톤이 이 글에서 집중적으로 추궁하는 것은 ‘과연 지각(perception)이 지식이 될 수 있는가’하는 문제이고, 그것은 ‘So man proves to be the criterion of what exists; everything that appears to man also exists; what appears to no man does not exist’라는 프로타고라스 이론에 대한 고찰이다. 소크라테스와 테아에테토스의 긴 대화의 결론은 지각의 그 근본의 취약성과 오류의 가능성(이 부분은 확실하지는 않다)으로 지식으로서의 자격을 박탈당하고 만다.

플라톤이 봉착하고 있었던 문제와 그 문제의 해결책으로 제시하고 있는 방책은 다음과 같이 제시될 수 있다.

 

In the whole of Plato's philosophy we may think of him as trying, by a more careful examination of the arguments, to find synthesis between the Heraclitan or Cratylan view, which he accepted, that the world of appearances is a multifarious flux, and the Parmenidean doctrine that reality is one and unchanging. He found it, as we shall see, by postulating two worlds, a world of sense, always in flux, and a unified world of Ideas, not available to our senses but only to thought, which alone are fully knowable. But the two-world view itself can plausibly be attributed to Parmenides, together with the associated distinction, so important to Plato, between knowledge (which is of reality) and mere opinion (which is concerned with appearances). (13, R. M. Hare, Plato, Oxford)

 

다시 말해 시시각각으로 변화하는 우리의 현상계만이 유일한 실체라고 상정할 경우에는 철학적 고찰이 출발할 지점을 찾기가 어려워진다. 또 현상계가 보여주는 이러한 불확실성과는 대조적으로 수학적 세계는 현실의 그 무엇이 깰 수 없는 확실성을 보여준다. 이러한 상황에서 플라톤은 파르메니데스의 영향 아래 ‘형상 세계’를 상정하게 되고, 그것에 점차적으로 확실성을 부여한 것으로 보인다. 섣부른 결론이긴 하지만, 플라톤은 헤라클레이토스와 파르메니데스를 변증법적으로 결합하고 있지만, 궁극적으로는 파르메니데스의 입장에 경도되고 있다고 말할 수 있다.

이 글에서, 플라톤은 인식의 불확실성을 ‘형상’을 도입하지 않고 해결해 보려고 하지만, 결국에는 해결을 못 본 채 글을 매듭짓고 만다. 이 글에서 플라톤은 전기의 저작들보다도 한층 더 성숙된 모습으로 문제에 접근하고 있다.

 

 

 

 

*This search into the nature of knowledge can be seen in its profound seriousness only when the reader keeps before him that to Socrates virtue was knowledge. To be wise was to be good. The text of the dialogue might well be Christ's saying, "He that willeth to do the will of God shall know the doctrine." To Plato always Socrates' life and death were the final proof of his truth. (845)

 

[from F. M. Cornford, Plato's Theory of Knowledge.]

 

#Introduction

 

*The sight of nearly equal things causes us to think of Equality, and we judge that they fall short of that ideal standard. It is argued that we must have obtained knowledge of true Equality before we began to use our senses, that is to say, before our birth; and this carries with it the pre-existence of the soul. Whether the argument seems sound to the modern reader or not, Anamnesis is accepted by all parties and later reaffirmed (92A); nor is any doubt ever cast upon it in Plato's other works. The upshot is that the Forms have an existence separate from things as surely as the spirit has an existence separate from the body. (5)*The most formidable consequence of recognising a Form for every common name would be that no limit could then be set to the world of Forms. The unlimited cannot be known, and if the Forms are unknowable, their raison d'etre is gone. But Plato leaves this question without an answer. (10)

 

#Text

 

*Like the midwife who is past childbearing, Socrates' function is not to produce his own ideas and impart them to others, but to deliver their minds of thoughts with which they are in labour, and then to test whether these thoughts are genuine children or mere phantoms. (17)

*So man proves to be the criterion of what exists; everything that appears to man also exists; what appears to no man does not exist. (35) (Protagoras의 이론)

*He <Plato> will later point out that the unrestricted assertion, 'All things are always changing', makes knowledge impossible. (36)

*The atheists of Laws X (889 ff.) draw the same contrast between Nature and convention. Fire, Air, Water, and Earth exist by nature and chance, without design; and by the interplay of their active powers--hot, cold, dry, moist, etc.--produce the whole physical cosmos. But art or design arises only later; it is mortal and of mortal origin. The whole of legislation, custom, and religion is 'not by nature, but by art'. Conventions differ in different communities. 'What is right has no natural existence at all; but men are perpetually disputing about it and altering it, and whatever alteration they make at any time is at that time authoritative, owing its existence to design and the laws, not in any way to nature'.

. . . To Plato this thesis is the position of the arch-enemy. (83)

*It is true that he <Anyone who gives his life to philosophy> is unaware what his next-door neighbour is doing, hardly knows, indeed, whether the creature is a man at all; he spends all his pains on the question, what man is, and what powers and properties distinguish such a nature from any other. (85) (S)

*Take heat, for example. When some layman believes that he is going to catch a fever and that this hotness is going to exist, and another, who is a physician, believes the contrary, are we to suppose that the future event will turn out in accordance with one of the two opinions, or in accordance with both opinions, so that to the physician the patient will not be hot or in a fever, while he will be both these things to himself? (90) (S)

*we may quite reasonably put it to your master that he must admit that one man is wiser than another and that the wiser man is the measure, whereas an ignorant person like myself is not in any way bound to be a measure, as our defence of Protagoras tried to make me, whether I liked it or not. (91) (S)

*Plato's point is that, if 'all things' without exception are always changing, language can have no fixed meaning. In the statement 'Perception is knowledge' the meanings of the words must be constantly shifting. So the statement cannot remain true or the same statement.

The Heracleitean Cratylus, who influence Plato in his youth, did in fact reach this conclusion. . . . Cratylus, who finally did not think it right to say anything but only moved his finger, and criticised Heracleitus for saying it is impossible to step twice into the same river; for he thought one could not do it even once.' (99)

*Without the Forms, as his Parmenides said, there can be no discourse. (99)

*Knowledge requires terms that will have a fixed meaning and truths that will remain true. (101)

*The following refutation proves (1) that perception cannot be the whole of knowledge for a great part of that is always called knowledge consists of truths involving terms which are not objects of perception; and (2) that, even within its own sphere, the objects of perception have not that true reality which the objects of knowledge must possess. Hence, so far from being co-extensive with knowledge perception is not knowledge at all. (102)

*It is clear to me that the mind in itself is its own instrument for contemplating the common terms that apply to everything. (104) (T)

*Is it not true, then, that whereas all the impressions which penetrate to the mind through the body are things which men and animals alike are naturally constituted to perceive from the moment of birth, reflections about them with respect to their existence and usefulness only come, if they come at all, with difficulty through a long and troublesome process of education? (107) (S)

*in the case of objects one does not know and has never perceived, there is, it seems, no possibility of error or false judgement, if our present account is sound; but it is precisely in the field of objects both known and perceived that judgement turns and twists about and proves false or true--true when it brings impressions straight to their proper imprints; false when it misdirects them crosswide to the wrong imprint. (125) (S)

*the misfitting of thought and perception cannot be a definition of false judgement in general. But it serves to bring out the need for some enlargement of the empiricist apparatus--some further distinction between the meanings of the word 'know'. (130)

*How can I know that I know? How can I recognise knowledge when I have it and be sure that it is knowledge? (140)

*Knowledge is produced by instruction, always accompanied by a true account of its grounds, unshakable by persuasion, and possessed by gods and only a few among men. True belief is produced by persuasion, not based on rational grounds, can be changed by persuasion, and is possessed by all mankind. (141)

*Since a syllable is a unitary thing, having no parts into which it can be analysed, it is simple, inexplicable, and unknowable for the same reason as the letter. This is the conclusion which completes the dilemma. (149)