Tractatus Logico-Philosophicus

we can picture it to ourselves.

3.01

The totality of true thoughts is a picture of the world.

3.02

A thought contains the possibility of the situation of which it is the thought. What is thinkable is possible too.

3.03

We cannot think anything unlogical, for otherwise we would have to think unlogically.

3.031

It used to be said that God could create everything, except what was contrary to the laws of logic. The truth is that we could not say what an “illogical” world would look like.

3.032

To represent in language anything that “contradicts logic” is as impossible as it is in geometry to represent by its coordinates a figure that contradicts the laws of space; or to give the coordinates of a point that does not exist.

3.0321

While we can represent a situation spatially that would contradict the laws of physics, we cannot represent one that would contradict the laws of geometry.

3.04

If a thought were correct a priori known independently of experience, it would be a thought whose possibility ensured its truth.

3.05

Only if the truth of a thought could be recognized from the thought itself (without an object of comparison) could we know a priori known independently of experience that a thought is true.

3.1

In a proposition, a thought finds an expression that can be perceived by the senses.

3.11

We use the perceptible sign...