Between the 1780's and the 1880's, a flowering of philosophy occurred in the German-speaking world such as no other period since the ancient Greeks had witnessed. It began with Immanuel Kant. Kant's work was enriched and extended by Schopenhauer. Fichte and Schelling also developed on Kant's ideas. Hegel produced a philosophy of absolute idealism. Marx adopted Hegel's framework and vocabulary, but substituted materialist values for Hegel's idealist concepts. Nietzsche performed an onslaught on existing morality. The wealth of ideas produced by these philosophers nourished many of the intellectual developments of the twentieth century.

Immanuel Kant (1724-1804)

At the age of 57, he published one of the great books of all time, Critique of Pure Reason (1781). It is a masterly synthesis of rationalism and empiricism, both of which put forward a one-sided view of knowledge.While the rationalists held that human knowledge is based solely on objective judgements of the intellect, and the empiricists argued that the mind is a "tabula rasa" or blank slate, Kant emphasized the role of the human mind in constructing reality and knowledge. He argued that knowledge could be gained only through a synthesis of experience and understanding.

Before Kant, philosophers thought that the only significant limit to human knowledge was set by what exists. That is, we can attain knowledge about anything that exists. In other words, one can go on finding out more and more, until there is nothing more left to find out.

However, Kant insisted that human knowledge is also limited by our bodily apparatus. This means that our body can do or understand many things. The sum total of all that our body deals with constitutes our knowledge. 

This means that what is delivered to our consciousness is the product of our bodily apparatus. In other words, what we see, hear or think are not objective realities, but products of our eyes, ears or brains. This means that sights, sounds or ideas are not objects external to us; they are representations of those objects and exist only in the human apparatus that produces them.

These ideas can be summed up like this: On the one side, we have the world of things as they appear to us-the world of phenomena. This is the world of possible knowledge for us, but all forms of this knowledge are subject-dependent. On the other side, there  the world of things as they are in themselves, the noumenal world. Its existence has nothing to do with human experience of these things. For that very reason, we can never access this realm, which Kant calls "transcendental" (exists, but cannot be experienced).

Kant did not consider metaphysics as a science of the supra-sensory, or of what lies beyond experience, but as a "science of the limits of human reason." Human reason goes beyond those questions that can be answered purely based on experience. For Kant, a priori ("from what came before") knowledge is transcendental and beyond all possible experience, while a posteriori ("from what comes after") knowledge empirical, and based on the content of experience. [For example, "Triangles have three sides" is a priori knowledge; "Some dogs bite" is a posteriori knowledge.] A priori is universal and necessary knowledge, while a posteriori is contingent and particular knowledge.

These ideas form the basis of Kant's philosophy, which is called "Transcendental idealism." To sum up, transcendental idealism is an epistemological approach, that is, it deals with the nature of human knowledge. Kant defines it as the understanding that one's experience of things is about how they appear to that person (phenomenon), not about those things as they are in and of themselves (noumenon).

Through Transcendental idealism, Kant effaced the differences between rationalism (reason determines truth), idealism (an ideal reality exists above the material reality), and empiricism (sense perception is more important than reason or the ideal). Kant's transcendental method acknowledges the a priori (transcendental) mental functions that determine the way people process any information. This method stresses both the reliability of science and the inability to know what transcends observable phenomena.

Before Kant, no other philosopher had given so much importance to the transcendental level of knowledge. Kant's Transcendental idealism accomplished a paradigm shift in philosophy and led to the development of critical philosophy, that is, the notion of being able to discover and systematically explore possible inherent limits to our ability to know through philosophical reasoning.

The main challenge to Kant's approach has been regarding its dualism that it does not clearly show how it is possible to both affirm the existence of an independent reality and state that nothing can be said about it.

Karl Marx (1818-1883)

Born in Treves, Germany, to Jewish converts, Karl Marx was a professed atheist who studied law, philosophy and history. When the newspaper he worked for was politically suppressed, Marx left for France. It was in France that he met Friedrich Engels with whom he collaborated for the rest of his life.. Back in Germany on a brief stint, Marx and Engels produced their Communist Manifesto in 1848. Further political persecution and poverty forced Marx to live the latter part of his life in England, where he wrote his seminal work, Das Kapital.

Marxism proved to be such a rich and influential system of thought because it fused together three intellectual traditions that were already highly developed: German philosophy, French political theory and British economics. The main points of Marxism can be summarized as: 

(i) Reality is not a state of affairs but an on-going historical process.

(ii) The key to understanding reality is to understand the nature of historical change.

(iii)Historical change is not random; it follows a discoverable law. 

(iv) This law of change is the "dialectic," with its repeated triadic movement of thesis, antithesis and synthesis.

(v)What keeps this law perpetually in operation is "alienation," which ensures that each successive state of affairs is eventually brought to an end by its own internal contradictions.

(vi)The dialectical process is not under the control of human beings, but is driven forward by its own internal laws, and human beings are swept along by it.

(vii) This process will continue until a situation is reached in which all internal contradictions have been resolved, and there will be no further alienation or change.

(viii) When this conflict-free situation is reached, human beings will no longer be swept along by forces outside their control; they will for the first time take their destiny in their own hands and will be arbiters of change.

(ix)This will, for the first time, make human freedom and self fulfillment possible for human beings.

(x)Such a society will be an organic society in which individuals do not function independently, but are absorbed into a much larger whole, thus providing the individuals an existence that is more fulfilling than their separate lives. Marx thought that the historical process was one of material change, and was in favour of a purely atheistic "dialectical materialism."Marx passed an equally drastic verdict on both religion and philosophical systems, which are forms of escape from, as well as expressions of, harsh, heartless and mindless conditions. Religion and philosophy, as well as social and political institutions, the arts and so on are all part of the superstructure of a material / economic base, which comprises the relations and forces of production.

To illustrate the relation between the base and superstructure, Marx drew attention to the fact that in the earliest stage of industrialization, when transport of raw materials was done chiefly by boat, and when mills and factories were still dependent on water power, industrial towns developed along river banks and sea coasts. But with the development of steam power, towns began to flourish near the sources of raw materials, or near the chief markets. This is an outstanding example of change in means of production bringing about changes in superstructure.

Thus, for Marx, economic relations form the base of the society. In other words, the most basic condition of humanity is to convert the raw material of the natural world into the material goods necessary for survival.That is, production or economic relations is the primary conditioning factor of life.

According to Marx's dialectical materialism, the history of human society is the history of class conflict. The landowners of the erstwhile feudalistic society were opposed by the rise of the middle classes, forcing a "synthesis," that is, a new economic class-the industrial employers of capitalism. Marx famously said, "The hand-mill gives you a society with the feudal lord; the steam-mill a society with the industrial capitalist." However, the capitalist class itself becomes a "thesis" which generates the antithetical force of the proletariat, or the working classes. The synthesis that Marx envisaged from this conflict, the inevitable dialectical outcome, is the emergence of socialism.

In the socialist society, the means of production would be owned by all and operated in the interests of all. Society, being class-free, would be conflict-free. Thus, for Marx, the industrialist capitalist society of his day was the last-but-one stage of historical development before the advent of the final conflict-free society.

In Das Kapital, Marx argues that labour is the source of all value, and that capitalist profit is the result of the economic exploitation of the worker by means of the "extraction of surplus value" - additional value created by the worker's labour that cannot be recompensed with a salary. Thus the capitalist system is innately exploitative and within it the majority of people are unable to live lives worthy of human beings. This is because within capitalism, the human existence becomes alienated from the human "essence."

In Marx's view, only under communism-with common ownership of property and production-can we recapture the human essence and live a life worthy of human beings. This will involve making full use of each individual's productive capabilities and seeing other human beings as fellow members of a human community with valid needs rather than as mere sources of profit. Marx believed that communism cannot be achieved merely by force of reason or argument. Capitalism will give way to communism,and eventually to a classless society,only as a result of revolution by the workers

The German philosopher Edmund Husserl is remembered as the father of phenomenology, that is, the philosophical study of human consciousness, which lies at the heart of all existentialist philosophies. He studied his own consciousness and used his findings to answer traditional philosophical questions. This method might seem subjective, but, paradoxically, Husserl's aim was to develop an objective and scientific foundation for all human knowledge.

When Husserl studied consciousness, he realized that we are never merely conscious, but we are always conscious of something-of a book or a headache, for example. Husserl's Phenomenology is a radical approach to the study of consciousness by studying the objects of conscious awareness. In this Husserl was influenced by the philosopher Brentano's concept of "intentionality." Now, what is intentionality?

I am currently sitting in my room, taking my online class. As I look around me, I see various physical objects. I am also thinking about a meeting I have to attend this evening, and about God. These and other mental states are directed towards the objects that I perceive. Brentano calls those things to which our mental states are directed "intentional objects." Whether or not God exists, God is in the very least an intentional object. The dagger that Macbeth hallucinates before him is an intentional object, despite not being real.

Thus, "intentionality" is the idea that all conscious states relate to a content, regardless of whether or not that content actually exists.

Though influenced by Brentano, Husserl's starting point was Descartes, with whom he agreed that there is only one thing we can be absolutely sure of-consciousness awareness.

Husserl re-defined intentionality. Because we are always conscious of something, consciousness could be defined as "directed towards an object." Whether or not something actually exists, it is an "object of consciousness," as far as we are concerned. In other words, objects are "appearances" to us, rather than things in themselves. Husserl called this "phenomenological reduction." The problem of whether or not things existed had to be put aside- "bracketing" was the term he used for it. Thus, phenomenology is a system based on the premise that reality consists of objects and events as perceived in human consciousness and not existing independently of it.Though Husserl's views have been challenged by critics, his influence was immense, especially on thinkers like Martin Heidegger and Jean-Paul Sartre