Tractatus Logico-Philosophicus | Page 9

there corresponds a positive fact, and to the fact that a
point is white (not black), a negative fact. If I designate a point on the
sheet (a truth-value according to Frege), then this corresponds to the
supposition that is put forward for judgement, etc. etc. But in order to
be able to say that a point is black or white, I must first know when a
point is called black, and when white: in order to be able to say,'"p" is
true (or false)', I must have determined in what circumstances I call 'p'
true, and in so doing I determine the sense of the proposition. Now the
point where the simile breaks down is this: we can indicate a point on
the paper even if we do not know what black and white are, but if a
proposition has no sense, nothing corresponds to it, since it does not
designate a thing (a truth-value) which might have properties called
'false' or 'true'. The verb of a proposition is not 'is true' or 'is false', as
Frege thought: rather, that which 'is true' must already contain the verb.
4.064 Every proposition must already have a sense: it cannot be given a
sense by affirmation. Indeed its sense is just what is affirmed. And the
same applies to negation, etc.
4.0641 One could say that negation must be related to the logical place
determined by the negated proposition. The negating proposition
determines a logical place different from that of the negated proposition.
The negating proposition determines a logical place with the help of the
logical place of the negated proposition. For it describes it as lying
outside the latter's logical place. The negated proposition can be
negated again, and this in itself shows that what is negated is already a
proposition, and not merely something that is preliminary to a

proposition.
4.1 Propositions represent the existence and non-existence of states of
affairs.
4.11 The totality of true propositions is the whole of natural science (or
the whole corpus of the natural sciences).
4.111 Philosophy is not one of the natural sciences. (The word
'philosophy' must mean something whose place is above or below the
natural sciences, not beside them.)
4.112 Philosophy aims at the logical clarification of thoughts.
Philosophy is not a body of doctrine but an activity. A philosophical
work consists essentially of elucidations. Philosophy does not result in
'philosophical propositions', but rather in the clarification of
propositions. Without philosophy thoughts are, as it were, cloudy and
indistinct: its task is to make them clear and to give them sharp
boundaries.
4.1121 Psychology is no more closely related to philosophy than any
other natural science. Theory of knowledge is the philosophy of
psychology. Does not my study of sign-language correspond to the
study of thought-processes, which philosophers used to consider so
essential to the philosophy of logic? Only in most cases they got
entangled in unessential psychological investigations, and with my
method too there is an analogous risk.
4.1122 Darwin's theory has no more to do with philosophy than any
other hypothesis in natural science.
4.113 Philosophy sets limits to the much disputed sphere of natural
science.
4.114 It must set limits to what can be thought; and, in doing so, to
what cannot be thought. It must set limits to what cannot be thought by
working outwards through what can be thought.

4.115 It will signify what cannot be said, by presenting clearly what
can be said.
4.116 Everything that can be thought at all can be thought clearly.
Everything that can be put into words can be put clearly. 4.12
Propositions can represent the whole of reality, but they cannot
represent what they must have in common with reality in order to be
able to represent it-- logical form. In order to be able to represent
logical form, we should have to be able to station ourselves with
propositions somewhere outside logic, that is to say outside the world.
4.121 Propositions cannot represent logical form: it is mirrored in them.
What finds its reflection in language, language cannot represent. What
expresses itself in language, we cannot express by means of language.
Propositions show the logical form of reality. They display it.
4.1211 Thus one proposition 'fa' shows that the object a occurs in its
sense, two propositions 'fa' and 'ga' show that the same object is
mentioned in both of them. If two propositions contradict one another,
then their structure shows it; the same is true if one of them follows
from the other. And so on.
4.1212 What can be shown, cannot be said.
4.1213 Now, too, we understand our feeling that once we have a
sign-language in which everything is all right, we already have a
correct logical point of view.
4.122 In a certain sense we