Ludwig Wittgenstein led a remarkable life, which is a topic all of its own.
Here I shall give a short overview of his two philosophies.
As a PoW of the Italians, LW wrote his Tractatus Logico-Philosophicus, with which he claimed to have solved the problems of philosophy, so he became a village schoolmaster (after working in a Monastery garden).
This is a very odd – aphoristic – book, with formal logic intermingled, towards the end, with what is almost mysticism. It is not long. It has to do with the limits of language: Of what we cannot speak, we must pass over in silence (Wovon man nicht sprechen kann, darüber muss man schweigen).
Wittgenstein’s language in his later work is straightforward. There are hardly any references. Between the lines he is arguing against positions which have been entrenched in Western philosophy from the outset.
One needs to know the background a little. In the late 19th century, a German by the name of Gottlob Frege did some original work on logic and mathematics. At the beginning of the 20th Bertrand Russell and Alfred Whitehead spent ten years trying to give simple arithmetic a sound footing in logic. Their brilliant work failed, but they did explain why it could not succeed. As an aviation engineering student in Manchester, Wittgenstein visited Russell in Cambridge, which is where things took off. Then came the war.
One of the ideas, or even the main one, underpinning the Tractatus is that sentences depict reality.
At the end of the twenties Wittgenstein had second thoughts and returned to Cambridge. There are many draft notebooks and also notes taken by his students, while his masterwork, the Philosophische Untersuchungen (Philosophical Investigations) was itself only published some time after his death in 1951. The uninitiated quite like reading this, but cannot quite make out what he is up to.
He is again looking at how language relates to the world. He is arguing against persistent ways of categorising things. For example, he points out that things might belong together not because they share some common feature, but because there are clusters of features which can be discerned. He calls this Familienähnlichkeit – think of a family photo, which of course figures people who are not all genetically related, so they do all share any specific physical feature, but there are strands, like hair colour, shape of nose etc. which overlap.
He asks whether there could be a private language. (No.) Like I might think I could create a language to describe to myself my emotions and perceptions, which no-one else can have.
He invents the concept of a language game (Sprachspiel). For example, natural scientists have a language game quite different to that used for religion or aesthetics.
I find his most useful idea is of language as a toolkit. Language provides us with various ways of dividing up the world, and then re-assembling it. Problems arise because these concepts come to be seen as absolutes and get applied outside their proper sphere. Language is idling. We often seem to be saying something when in fact we are talking nonsense. On the surface the sentences are grammatical and the words are all in the dictionary, but at a deeper - logical - level they are ungrammatical.
One task of the philosopher is to intervene when we are applying language (thought) improperly – when we have left the limits of the language game. Think of a chessboard which has been peppered with salt cellars.
This is an important hallmark of the Anglo tradition (or what was the Anglo tradition): Philosophy is an activity. You do not have a philosophy, like you might have a Weltanschauung, a world view. Philosophy is something you do.
Witgenstein says the proper procedure in philosophy is to let someone talk and to intervene when, theorising, they drift into speaking nonsense.
My personal understanding of philosophy today (not historically) is that it seeks out hidden assumptions. The late Mary Midgley (a Wittgesteinian, 1919-2018) put it well by seeing it as similar to plumbing. Something stinks, so you have to get down and look at the pipes and all. Foul concepts and confusions, with the sewage commingling with the tap water.
My recommendation for an understanding of Wittgenstein is not the many books about him (there is a whole academic industry now) but to read something by Mary Midgley, which will not mention Wittgenstein much by name, but it is inspired by him. Midgley is a supreme philosopher of science. She demolishes anything resembling scientism. Very readable.
The late Wittgenstein is an ordinary language philosopher. When he is difficult, this does not come from obscure concepts or convoluted sentences, but because he is saying something unusual.
In a way what he does is to satirise philosophers (i.e. those of his time and before). He says you must think even more wildly than the philosophers in order to bring them back to earth. He turns things on their head. Although he seems to have been a humourless man, earnest and tortured, he pokes fun at the philosophers.
Another major strand in the Philosophische Untersuchungen is the examination of what it means to follow a rule. Wittgenstein said little about ethics, and what he did say is questionable, but in his preoccupation with rules he might be thought of as shadow-boxing ethics.
End of remarks on Wittgenstein
Universalising words are insidious. I might use a word like ethics precisely, having defined it by distinguishing it from neighbouring concepts, but others will use such abstractions loosely to express sentiment, or rhetorically to provoke sentiment.
Some words defy definition. Notoriously, the word “good.” Over a century ago this was the subject of a still famous book by G.E. Moore (older colleague of Ludwig Wittgenstein), Principia Ethica. You can always ask of something held high (like pleasure, or fidelity), but is it good? It is a free-floating, open-ended concept. Just as one can always add one more to a series of natural numbers, which stretch indefinitely, or always search out a further cause in a chain of cause-and-effect.
In one famous debate about fundamentals one of the disputants made the point to their opponent that they actually agree at a practical level, it is just on the theory that they are at loggerheads.
Any of these big concepts can be broken down and interrogated, even something like Truth.
So, nimm dich in Acht vor großen Tieren! (Beware of large animals!)
My solution is that these are like planets in a solar system, or numbers in a matrix. You cannot understand any of the concepts on its own, but only in terms of how it relates to the others. There is no one overarching concept. It is partly this that is meant by immanence