The third part, Fundamental Knowledge, introduces some concepts which are uniquely Jaspers’. The approach of the book however is to make statements without much backup of argumentation or without indicating what statements are peculiarily Jaspers’.

Part III is where things get very difficult. Jaspers looks at what it means “to be” /”to exist”. Being is always 2-sided, with both subject and object, the perceived and the perceiver. J. doesn’t even bother to argue against naïve realism (the notion that only physical objects are real). Humans, he writes, are where “what is” is revealed.
So “what is” is problematic right from the start: it is split between perceived / perceiver or I/objects. Historical attempts to view “what is” as purely objects or as purely perceptions both fail.

Our minds are hard-wired to think in terms of objects. We always want to form a concept of a thing, a fact, a state-of-affairs. We resist acknowledging that “what is” cannot be contained in this way of thinking.

The subject/object fissure is the basic structure of consciousness.

J. then goes on to look at different aspects of “what is/what we are”. There are things we see and touch and our ability to move and survive among them. This corresponds to the consciousness of an animal.
Then there is thinking as such. Thinking can be correct or incorrect. (I think ‘logical thinking’ is what he means).

He addresses the question of whether Political freedom is founded in human nature.

The reality of the overwhelming majority of nations and states testifies against political freedom.

In general in Jasper’s thought I can perceive a tension between logical consistency and reality. A universe of whirling particles obeying Newtonian physics can be pictured and described. It is a neat image.
But it doesn’t capture reality, and has been rejected in favour of quantum physics. Things get messy, the observer becomes an indespensable part of the universe. But the observer is not an object.
Yet still we might insist on a minimalist interpretation of ‘what is real’, and say, OK we admit there are observers. But truth and free will and despair and all that other messy stuff, that’s definitely not real, it’s just concepts created by the human animal.

That’s an attractive viewpoint. But take for example a mathematical statement and its proof. We say the statement is true. You can try to unpack that meaning into psychological terms of the behaviour of humans. (For example that peer mathematicians will also declare it to be a proof.) But in making such a mathamatical statement we don’t intend to make a statement about how human minds operate. We are not saying “similar minds to my own will have a chain of experiences as they read through this proof, which will result in them behaving in a manner that is consistent with their having the belief ‘this statement is true’.”

The correctness or incorrectness of a maths proof is not a property analogous to properties such as mass and momentum. But it cannot easily be dismissed as having less reality.

Parmenides went to an extreme of insisting that what was real is solely what the mind can readily grasp. So we see an arrow in flight. The arrow is real. At each moment in time it has a different position. We can picture the arrow with perfect clarity at a specific point in time. The sharp point, the shaft, and the feather at the back.

But motion is not a part of the arrow. To talk about motion is to talk about where the arrow was and where it will be a moment later. At a fixed point in time, how can the arrow have motion? We can look at a snapshot of an arrow, and not know whether it is moving fast or slow.
Motion, Parmenides concludes, is not real. It is a concept added by humans. We live in a world of illusions.

Parmenides’ mistake is to insist that what is real is what is amenable to thought.

A philosophy which insists on objectivity/consistency will squeeze out whole sectors of experience and consign them to a dustbin marked “murky feelings and beliefs and stuff”.

Chapter X where he talks of The Ciphers comes across as fuzzy neoplatonism.

As usual, Jaspers doesn’t argue against supposed objections to his thesis; he just describes. In any case, what he seeks to elicit is an encounter of thought with philosophical questions.

But he is fascinating (to me anyway) where he talks of how the Greek gods are a historically unique creative encounter with man’s fractured nature: to reflect it, and also understand it and give it form.

At the forefront of Jaspers’ thought is the legitimacy of “philosophising” itself, as distinct from the study of different philosophies, or psychology.