Schopenhauer, thinking for oneself > Reading is thinking with some one else's head instead of one's own. But to think for oneself is to endeavour to develop a coherent whole, a system, even if it is not a strictly complete one. Nothing is more harmful than, by dint of continual reading, to strengthen the current of other people's thoughts. These thoughts, springing from different minds, belonging to different systems, bearing different colours, never flow together of themselves into a unity of thought, knowledge, insight, or conviction, but rather cram the head with a Babylonian confusion of tongues; consequently the mind becomes overcharged with them and is deprived of all clear insight and almost disorganised. This condition of things may often be discerned in many men of learning, and it makes them inferior in sound understanding, correct judgment, and practical tact to many illiterate men, who, by the aid of experience, conversation, and a little reading, have acquired a little knowledge from without, and made it always subordinate to and incorporated it with their own thoughts. Wittgenstein, PI p149. > tell me what the object of painting is: the picture of the man (for example), or the man whom the picture portrays? > Later Hume will divide all objects of human reason into 'Relations of Ideas' and 'Matters of Fact'. The former are certain and do not necessarily say anything about what actually exists in the world; the latter do make claims about the world, but "the contrary of every matter of fact is still possible". With this in mind it can be asked what status holds for the claim that "all our ideas or more feeble perceptions are copies of our impressions or more lively ones". If this is a Relation of Ideas, then it does not necessarily say anything true about the world, and this will not suit Hume's purpose at all; if it is a Matter of Fact, then the contrary must be possible. The inconsequential hypothetical possibility that we are able to raise up to ourselves the idea of the missing shade of blue, even if in practice this does not ever happen, will ensure that Hume's description of the origin of ideas is grounded in fact. > However, what is required of matters of fact is the logical possibility that they could be other than they are, not the practical possibility. This being the case, it is not necessary to construct an elaborately worked out example; it would be sufficient to say that we might have been constituted differently. [https://en.wikipedia.org/wiki/The_Missing_Shade_of_Blue#Hume_needs_an_exception](https://en.wikipedia.org/wiki/The_Missing_Shade_of_Blue#Hume_needs_an_exception) The close connection between the interpretationalist hypothesis and a holistic conception of beliefs is at the root of the notion of the dependence of perception on theory, a central concept in The Structure of Scientific Revolutions. Kuhn maintained that the perception of the world depends on how the recipient conceives the world: two scientists who witness the same phenomenon and are steeped in two radically different theories will see two different things. According to this view, our interpretation of the world determines what we see.[[61]](https://en.wikipedia.org/wiki/The_Structure_of_Scientific_Revolutions#cite_note-61) [Jerry Fodor](https://en.wikipedia.org/wiki/Jerry_Fodor) attempts to establish that this theoretical paradigm is fallacious and misleading by demonstrating the impenetrability of perception to the background knowledge of subjects. The strongest case can be based on evidence from experimental cognitive psychology, namely the persistence of perceptual illusions. Knowing that the lines in the [Müller-Lyer illusion](https://en.wikipedia.org/wiki/M%C3%BCller-Lyer_illusion) are equal does not prevent one from continuing to see one line as being longer than the other. This impenetrability of the information elaborated by the mental modules limits the scope of interpretationalism. [https://en.wikipedia.org/wiki/The_Structure_of_Scientific_Revolutions#Incommensurability_and_perception](https://en.wikipedia.org/wiki/The_Structure_of_Scientific_Revolutions#Incommensurability_and_perception)