The Marxist theory of knowledge: how do we know things?

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How do we acquire knowledge? This central question in philosophy has confounded thinkers for millennia. On the one hand you have the idealists, who argue that truth exists a priori of the material world and finds its reflection in our minds – ultimately implying that knowledge comes from outside of nature - from a higher being.

Then there are the bourgeois materialists, whose main theory of knowledge (empiricism) states we can only know the content of our senses, making it impossible to talk with confidence about generalisation, causation – or even the existence of material reality outside of our own, direct experience.

Marxists argue that knowledge comes from the world, and it is by generalising our experience of the particular (e.g. burning ourselves) that we can form abstractions that let us comprehend the general (e.g. fire is hot). Thus, practice and concrete experience are the basis of knowledge. Meanwhile, passing our experiences on to one another allows us to develop human society, production, science and technique to ever-higher levels of complexity, thus deepening our knowledge of the world.

Transcription

Daniel: The problem of knowledge is possibly the most central question in all of philosophy. Surely, it’s the central question for bourgeois and contemporary philosophy. How it is that we form knowledge and whether or not that knowledge is objectively true is a very important theoretical question.

It has to be said that philosophy has gotten stuck on this question. It’s in a rut and it doesn’t know how to answer the problem of knowledge:, that is, how it is that we have knowledge. A huge proportion of contemporary bourgeois philosophers are what is known as skeptics, or even subjective idealists. Skepticism is the position of doubting knowledge and subjective idealism is a sort of extreme variant of that that says that all objective knowledge is impossible. For the best part of maybe even 200 years most of the trends of bourgeois philosophy have essentially concluded that there is no objective knowledge.

In the early days of the bourgeois revolution, and also the scientific revolution that went with it, the bourgeoisie produced philosophical geniuses. The likes of Bruno, Bacon, Spinoza, Locke, Diderot – they were not subjective idealists, but they did utilise scepticism in order to question all of the received truths and dogma of religion, which was a revolutionary thing to do. They were searching for a firm and scientific foundation for knowledge. They wouldn’t accept any appeals to God or to the nature of the soul as an answer as to why we have the ideas that we have.

The main trend at that time was optimism, a sort of materialist optimism, a belief in progress and that humanity would better itself by means of science. And the main idea they tended to have was that genuine knowledge comes from experience – it doesn’t come from the soul or from anything that God has given us, but it comes from experience of the world around us. However, following this initial revolutionary, heroic period for the bourgeoisie, bourgeois philosophy went into decline and it tended to become more conservative.

So the major philosophers of the subsequent period – that is people like Hume, Berkeley, and most famously Kant – based themselves on the previous philosophers, but they drew different conclusions. Essentially they concluded that we can’t really know anything objective about the world. We can’t know what the world is, and we can never escape from our own senses and our own minds. It’s a strange paradox that in that epoch, an epoch of unparalleled scientific advance, the main ideas of the philosophers were that knowledge is impossible.

To some extent that was a positive thing, as it reflected the need to question the received dogmas of religion. But it also reflected the limitations and the conservatism of the bourgeoisie as a class. And today this rut of subjective idealism has become a complete chasm from which stagnant bourgeois philosophy cannot escape.

Gone is the optimism in human progress and the use of science and reason to improve our lives. Philosopher after philosopher just chews over the cud of subjective idealism over and over again. Twentieth century philosophy was completely dominated by subjective idealism. At its beginning we had the logical positivists, the pragmatists, the empirio-critics; and later on we had the phenomenologists and the existentialists – and of course the post modernists. All of them in one way or another deny the possibility of objective truth, or knowledge of an independent material world.

They just keep churning these ideas out, and each time they reveal it as if this is a great new insight, a completely radical new idea. One of the latest examples of this is a psychologist called Donald Hoffman, who published a celebrated book called The Case Against Reality. In it, he says, “The universe itself is a massive social network of conscious agents that experience, decide, and act. If so, consciousness does not arise from matter, instead matter and space time arise from consciousness as a perceptual interface.”

It’s worth considering why it is that in this period of unparalleled scientific understanding, the dominant philosophy is that there is no knowledge. It’s because, despite the scientific advances that we have, those advances have no coherent direction to them. In many cases, science is simply used to destroy the environment, or to create ever more powerful killing machines. And even where that isn’t the case, even where science gives us something useful, it isn’t used to do that – it’s used to generate profits.

Under the domination of the bourgeoisie, science is merely a tool for selfish gain, which means that they’re not interested in a genuine, all round understanding of reality. They’re not interested in understanding. The typical mentality of the bourgeoisie is simply to use things that work, without really needing to understand why they work.

This is reflected very clearly in the methods of most bourgeois philosophy, which always start out from the atomized individual, ripped from their social context. They examine this abstract thought that no real person actually has, and they attempt to answer all of the philosophical questions relating to thought on that basis. It’s as if a biologist attempted to explain how an animal lives by finding a dead body of that animal and examining it under a microscope; instead of examining it in its real life, in the real environment that it actually lives in.

The logical basis for this is of course formal logic. Formal logic is a set of rules in philosophy which encourages us at the very least to put things into fixed categories – to freeze them, to not look at them in their motion (and ask where they’ve come from and what they depend upon), but instead to box them up into so many lifeless categories. And when this logic is applied to the problem of knowledge, it makes a resolution of the problem of knowledge impossible.

The philosophers take something that they call ‘subject’ and they counterpose it to ‘object’. Because object means the entirety of the material world and subject means either the individual thinker or thought in general. But they start out from this fundamental compartmentalisation: the subject, thought, is treated as if it is a self-contained, self-sufficient thing that just exists because that is the way that it is – it just happens to exist in that way. And the two sides are thus rigidly opposed. It is as if the mind is a magical thing, a soul, which comes into being and then somehow observes the material world – which is always treated as a fundamentally different thing, a different substance entirely. Of course, treating it in that way makes it completely impossible to understand how the mind, this totally non-material thing, can ever have genuine knowledge of something that is completely and utterly alien to itself.

To escape this rut we need to escape the bourgeois world-view – we must abandon the starting point of this abstract, timeless, classless individual. Instead, we must study consciousness just like other scientists study other natural phenomena. In other words, study it historically and in its real life, asking ‘where does it come from?’, ‘what is consciousness used for?’, and ‘what are its limits on that basis?’.

Marx summed up the need to do this brilliantly in his famous theses on Feuerbach. He said the following, “The question whether objective truth can be attributed to human thinking is not a question of theory but is a practical question. Man must prove the truth — i.e. the reality and power, the this-sidedness of his thinking in practice. The dispute over the reality or non-reality of thinking that is isolated from practice is a purely scholastic question.”

This is a brilliant insight, because Marx is essentially saying, “we’re asking the wrong question” or “we’re posing the question in completely the wrong way”. There is no solution to the problem in that scholastic manner. What Marx understood brilliantly is that thought is not disembodied. If it were, it would be absolutely incomprehensible. Why would you think this or that if your thought is based on some sort of timeless soul or some other spiritual substance? What would determine your desires, your passions, your emotions? What would motivate you to acquire this or that type of knowledge and apply it?

The only way to answer that theoretically is to understand the real material basis for thought. Which is to say that all actual beings think; in other words, all real people are themselves material, are objective beings, are part of the natural world.

The question of senses is a very important question for knowledge. The early empiricists of the bourgeois revolution were correct to say that knowledge is derived from sense experience, instead of coming from the soul or from other inherent properties of human reason. But their mistake, their limitation, was in seeing this experience purely on the level of the isolated individual. And in fact, lodged or implied in their theories was still the assumption that the thinking being is not a material being. We may gain knowledge via our senses of the material world, but the thing that actually gains that knowledge is not of the material world.

Hence the fact that, with Hume for example, and with Berkeley, the senses that give us our knowledge were seen as a barrier to genuine knowledge of the external world. They said that actually we are entirely dependent on what our senses give us; and of course our senses are not of the material world, they are of the mind. But dialectically, the senses are not a barrier between us and the external world; nor are they a bridge between a purely subjective world and an external objective word. Instead, the senses are a bridge between two different parts of the same world. And our senses themselves are a physical, material thing.

Now it’s important to stress that we are a part of the material world, but we shouldn’t abolish the difference between ourselves and the material world. Some philosophers have attempted to say that we do have objective knowledge. For example the German philosopher Fichte said that knowledge is possible, and that the objective world is not fundamentally different from us. Which might sound like the correct position, but what he meant is that we are identical with the external world. Because in fact there is no external world, everything is just a projection of the ego, the thinking subject.

For him, of course, we do have knowledge of these things because they’re actually just forms of ourselves, which is just a verbal trick and doesn’t resolve the problem of knowledge at all.

The thinking subject is not identical with the objective world; the objective, material world is independent of the thinking subject. It existed before us and is the basis for our existence, but since we are part of nature – since we are natural beings participating in nature in order to survive – then of course knowledge of the rest of nature is definitely possible.

Probably the most famous and influential argument of subjective idealism comes from Kant, who pointed out (correctly) that our knowledge comes via our senses, but knowledge is itself ultimately impossible without utilising certain abstract structures of the mind. The mind applies universal categories like cause and effect, time, big and small, etc. It applies those categories, those abstract categories, to sensory experience in order to make sense of it, to filter it and give it meaning.

But, he said, and this is where we disagree fundamentally, these categories are simply inherent properties of the mind. And therefore they make knowledge of, as he put it, “the thing-in-itself”, i.e. the material thing, outside and independent of consciousness, impossible. These categories that we apply to experience make knowledge of that thing as it truly is absolutely impossible, because we can never escape these categories; we can never think or experience without using them.

He sees these as inherent in the mind, in each individual taken separately. Every individual is born with these properties of the mind. This is because he starts out – like all these philosophers – from the abstract individual, the timeless, classless individual of his imagination; and therefore, if abstract consciousness must have these categories within it, then it must be a fundamental, inherent feature of everybody’s consciousness, taken separately.

Kant does highlight a very important point: it’s true that experience only becomes knowledge when we universalise it. So if I look out the window, what can I see? The only way I can explain and understand what I can see, is by giving it a universal category. In other words, I’m looking at trees, and those trees are green. Of course, each one of those trees is different – they belong to different species, and each one of them is a slightly different member of that species. Yet, I still call them trees and I still call them green.

Now, imagine if I didn’t do that. If I didn’t make use of any universal category such as tree, green, or anything like that. Obviously it would be impossible for me to communicate to anybody what I was looking at. Even I myself wouldn’t be able to understand what I was looking at, or what its significance was, unless I used categories like ‘tree’.

But as Hegel quite brilliantly pointed out in criticising Kant on this, what this shows is that the so-called ‘thing-in-itself’ shorn of these abstract categories such as ‘green’, is simply nothing. In fact, rather than being the way things really are outside of consciousness, this thing-in-itself is actually just a figment of the imagination. There is no such thing without these general properties. If you strip away these universal categories, do you get to something that is more unique, more truly what that thing is? Or do you just get to an even more abstract thing? In fact, he makes the point that it becomes more abstract the more you remove these universal properties.

All you could say about it, is that it’s a thing. In fact, that’s exactly the term that Kant used, the thing-in-itself. And of course, everything is a thing. So by removing these abstract, general properties we don’t get to a more unique, truer depiction of something, we actually lose what it really is. So it’s true, knowledge is a synthesis: it is a dialectical contradiction of two opposites, the individual thing and the universal category that it is part of.

But the mistake of Kant and many other philosophers is to assume that these universal categories, these ideas such as ‘greenness’ are just convenient fictions of the mind; that they’re just ways that the mind sorts itself out, but that have nothing to do with the way things truly are. It’s quite common to say that people don’t like it if they get categorised, if you say that they belong to a particular class; they want to be more unique than that.

Of course it’s true, there is no such thing as ‘time’, or ‘fruit’, or ‘trees’ as such, there’s only individual trees. We cannot find ‘time’, or ‘fruit’ as such, or the ‘tree’. We can’t look at these and say, “there it is, it really exists”. And so these people say that these are just ideas, they don’t really exist. Of course, as always with idealism, the problem with this is that it cannot explain the basis or the origin of these ideas.

If each mind, each thinking person, is born inherently with these abstract concepts lodged in their mind somehow, if they don’t come from reality – if they don’t really exist in the real physical world – then why on earth would we, as thinking beings, make use of these concepts and not others? What determines the concept of time, why is that the concept that we have and not something else? Moreover, without being expressed in real physical objects, what actually distinguishes any of these abstract categories from one another?

How can we say that time or space are different from one another and how can we define that difference without constantly applying it to real, physical things that exist in time and space, or are expressed in time and space?

Of course, Marxists are often accused of applying the category of class to individuals and ignoring their individuality. You do get people who are very insistent on their own individuality, and that they are not to be categorised as this or that type. So does the category of working class do violence to individuals? Do we, by applying it to individuals, lose something of what they truly are?

But what makes somebody an individual? Is the truest version of yourself the version of you that is stripped of all influence from those around you? And how do people usually define their individuality? Maybe they say, “I’ve got this really eclectic music taste” or “I’m really into these bands that nobody else is”. Or maybe they’re petty bourgeois and they say, “I’m unique really because I’ve worked very hard, I set up this company and I do all the work, and it’s truly my own thing”.

But if you enjoy particular kinds of music, obviously that means you listen to music that other people have made. Of course their ability to do so also depended on various economic and technological conditions. Similarly the petty bourgeois business owner clearly depends on the development of the economy, the technology available, etc. – and also people to sell to and buy from. They depend on all of this in order to have their business.

And above all, our ability to even think as individuals depends on the utilisation of language, and all of the knowledge that is contained in that language. Therefore, if you strip away everything that isn't that individual, you are left with very little. So these universal categories not only exist, but in a certain sense they are the deepest truth about what exists. They do not exist as individual things. There isn't an individual thing that is ‘time’ or that is ‘working class’, but they really do exist in and through the real relations that all of the individuals actually stand in.

So these universal categories don't exist somehow before or externally from the individual things. Of course we didn't have ‘fruit as such’ which somehow gave birth to apples and oranges and all other kinds of fruit; but at the same time individual apples and oranges don't simply pop into existence out of thin air.

The meaning, for example, of this category ‘fruit’ is that it expresses the history and the historical development of this kind of organic life and the relations that it stands in. Apples and oranges for example, couldn't exist without not just previous fruit, but in fact the entire prior history of evolution.

This brings me to what genuine, scientific, dialectical knowledge is. Frequently we think of knowledge of something as being just a list of its features. That is a kind of knowledge, if you can call it that, that is clearly based on formal logic; in other words, lifeless categorisation. So to understand what apples or oranges or human beings are, you notice the features that they tend to have in common, and then you just list them. Which tells us absolutely nothing about why that thing exists and has those features.

Dialectical knowledge of something is not that. Instead we seek to understand the real history, the process behind the thing in question, the internal contradictions that drive it forwards; as well as the general context that a thing exists within, what it depends upon, what it is constrained by, etc. Whereas most philosophies always tended to answer the question of universals by saying, “well it's either one or the other”.

In other words, the truth is either that all you have is individual objects, or others, like Plato for example, say that the real truth is these abstract, perfect ideas of which all of the material objects you see are just poor copies.

For Marxists, however, both are necessary. Real things can only exist because they are part of a general system that produces them, and that in turn will destroy them. But similarly, those general concepts or systems that they belong to cannot exist independently of the real individual objects that make them up. The fact that our ideas concern these universal categories, and constantly have to make use of them, does not block us from the way that things really are outside of these categories – because these universal categories are actually real. In other words, they express the real relations, the history between all of the parts and the system to which they belong.

But now we have to ask the question, how do we manage to get this knowledge? Now, as I mentioned, the empiricists of the beginning of the bourgeois revolution answered that we get knowledge and ideas from individual experience. At first glance that appears to be a materialist thing to say, and indeed a correct thing to say. But in fact, we do not cognize or understand the world immediately through our senses.

For example, a cat receives fundamentally the same sense information that we do. In fact, they probably receive largely better sense information, because their eyes and their ears are generally better than ours. But clearly, cats have far fewer ideas, a far worse understanding of the nature of the world around them than we do.

Now we are familiar with types of optical illusion – when you look at something, and for a moment you have no conception of what it is that you're looking at. There's a period where you cannot understand what the parts of it add up to. Perhaps you're not even sure exactly where the thing begins and where it ends; and then suddenly, for some reason you realise what kind of thing it is that you're looking at, and all the parts suddenly fall into place. It's quite a surreal experience when it happens.

Contemporary neuroscience is beginning to explain how this happens and how we really see things. What this shows us is that conscious beings are constantly sifting experience into categories, and this is a process which is heightened and sped up by the ideas that we already have; which of course, animals don't have.

In fact, those very few of the ideas that you have and that you are always using to make sense of the world as you experience it, have been generated from your own direct experience. The vast majority of it comes from the collective, accumulated experience of society, which is given to us through language and that all of us are socialised in as we grow up. And we constantly make use of this vast treasure trove of former experience, former ideas, or existing ideas from society in order to navigate the world.

This is one thing that the empiricists did not understand. The other thing that they did not understand was the active role of humans in acquiring knowledge. The way they depicted us as ‘experiencing beings’ was as isolated, passive individuals receiving sense data from the world. From the passive experience of that sense data, each of us would individually build up ideas about the world.

But of course if we were passive in that way, what would determine what it was that we learnt from our experience? What would make this or that experience particularly significant and worthy of learning from? In reality of course, the process by which society gains these experiences which produce knowledge is through practical activity; which is performed in order to meet our objective needs, since we are after all, natural beings that need to survive.

In turn, it is this labour of millions of people that determines the form that society has; and therefore, in general it determines what kind of experiences and needs humanity has, and so ultimately what kind of ideas humanity has.

I think this can also help us to resolve one of the other classic problems of philosophy, which is very similar to the problem of whether or not universals really exist. Philosophers, most famously Plato, pointed out that these universal ideas are always more perfect than the imperfect embodiments of them that we find in the material world.

For example, the idea of a circle is always perfect, whereas any actual thing that we call a circle is never really a perfect circle. It's always deficient in some small way. Of course, he concluded that therefore, the material world is not really true: it's an imperfect reflection of the higher reality.

The answer as to why these ideas appear to be perfect lies in the character of the social labour that produces these ideas. In other words, the accumulated practical experience of thousands or even millions of people gradually reveals the essential features of something, such as a circle, and discards what is inessential or imperfect.

Those who first started making wheels needed to have a general concept of the wheel to communicate to their children or to other people what they knew, and that needed to get at what was essential about a wheel. So it is labour that creates the need for an idea, that produces the content of knowledge; and this knowledge has a perfect or ideal form precisely because it's the product of not just one individual, but the collaboration of many people over a long period of time.

Throughout history, philosophers have been members of the ruling class, and so they neglected or had no understanding of this literally laborious process behind the formation of ideas. They take the thinking individual in an abstract form, completely removed from the historical process that produced those ideas that that individual has.

To these people, these powerful ideas seem almost magical, because they cannot understand the hundreds of thousands of years of pre-history that allowed us to generate those ideas. They concluded that ideas don't come from experience; they are something somehow better or removed from the material world. They treated consciousness and ideas not as a process but as a finished thing.

Finally, the last thing I want to discuss is how it is that we have false ideas, and what that means. Because clearly many of humanity's ideas turn out to be false. It’s tempting, then, to conclude that inevitably the ideas that we have today will turn out to be false, and therefore everything is false.

Dialectics teaches us not to think in these irreconcilable absolutes, such as that knowledge is either perfect or it is completely non-existent. Many philosophers are fond of pointing out that our senses deceive us, and certainly that is the case – everybody has flawed senses. But the fact that we can determine that somebody has flawed senses, and how and why they have flawed senses, tells us everything about the process of knowledge.

First of all, if we can show the cause of that person's flawed senses, then what does that mean? It means we're showing that their senses are material things, and we can measure and understand how they work. In other words, we are physical, material beings and our physical, material form determines our ability to know things. But also the ability to show somebody else's error tells us a lot about how knowledge advances. Our knowledge is, once again, not really a product of each individual taken separately, but the product of society.

Everybody's sense experiences and everybody's ideas are inevitably, to some extent, flawed or imperfect. Yet, it is possible for other individuals to see through that and to correct those mistakes, and thereby collectively advance human knowledge. Of course, technology here is vital, in the case of measuring somebody's senses and finding out that they're flawed. Obviously we use human technology in order to determine that. We can use technology to see things, for example, to see wavelengths of light that our own eyes are not capable of seeing; and that shows that there are and can be no absolute barriers to knowledge.

Everything is part of the same material world and so must, in some way, influence and be influenced by other things in the material world. Therefore, obviously, we can come to know the effects of those things, and ultimately to understand them. Human knowledge is of course never perfect, never finished, and many of our existing ideas will be shown to be false. But we should also say that the flawed ideas of yesterday are not just complete rubbish; there is truth within them, and without those ideas we couldn't have the knowledge we have today.

Also, the fact that many of our ideas are disproven doesn't mean that there's no objective truth; in fact it means the opposite. You cannot disprove something without inadvertently proving something else, and making use of objective reality to do so.

Lastly, I would say that it's not really true that everything turns out to be false; that's an exaggeration. We disproved that the earth is flat, but it would be rather mechanical to assume that, therefore, we will eventually disprove that the earth is round; as if everything will be equally disproven.

Will it be disproven that evolution proceeds via natural selection? Of course, Darwin's ideas will be and have been perfected and deepened; but the basic idea that he had is absolutely true and I don't think that will ever be disproven.

Similarly, Marxism will be and has been deepened, and of course individual Marxists make mistakes all the time. The fundamental ideas of historical materialism, however, the fact that the material world exists independently of us, are not going to be disproven.

To sum up, why are we having this discussion? Why does it matter to get our epistemological position correct? It is because the overthrow of capitalism and the establishment of a socialist society is no mean feat. It's not something we can stumble into blindly with our heads full of prejudices and other errors. Socialism doesn't mean slightly improving the lives of the working class: it means abolishing all class society and all privileges. It means humanity, for the first time, really understanding itself. And instead of being pushed and pulled along by this or that temporary pressure or narrow interest, it means consciously applying our scientific knowledge to solve the underlying problems of humanity.

Of course, this is only possible thanks to the incredible advances of science and productive technique over the past few hundred years. And it stands to reason that those who want to hold society back must also make use of retrograde ideas. Those who want to protect and preserve narrow interests must make use of illusions, prejudices and all kinds of other short-sighted notions.

Those who were revolutionaries, but are in the process of abandoning revolution, always retreat into subjective idealism. This is because they've given up the cause of understanding the world in order to change it; and they have to say that there are barriers and things we can't understand or do, in order to justify their position.

Yet despite all of this, humanity advances from one discovery to another. We need, therefore, a philosophical method that accepts this, and on the firm basis of human reason draws the optimistic conclusion that yes, we can and we must change society.

Marxism pulls aside the veil of mystery and shows us the real workings and the real history of humanity. We can and we do understand humanity, and on that basis we can and we will use this knowledge to establish a rational society that is socialism.

INTERVENTIONS

Ben: The empiricists see the acquisition of knowledge as very much a one-way street. To the empiricists, our senses are bombarded by the external world. And those sense impressions are the sole source of our knowledge. The English empiricist philosopher John Locke likened our minds to a blank sheet of paper, which for him is inscribed with thoughts and memories by the senses; in just the same way as a sheet of paper is inscribed by a pen.

In Marx's second thesis on Feuerbach, he explains that the question of the truth of our knowledge isn't just a question of observation. It's a practical question of testing the truth and the ‘this-sidedness’ of our knowledge in practice. It's through labour and through changing the world that mankind has come to know the world.

So how did our ancestors find out that some berries are edible and some are poisonous? They ate them; and some of them got quite sick, presumably. They found out that fire is hot by sticking their hand in the fire.

The working class comes to understand its own strength and its own interests through practice as well, through struggle. But for many decades the dominant ideas in neuroscience have been formed under the influence of empirical epistemology; and this has led to something of a schema, in which the brain is seen to operate as follows: our sensory neurons bring information into the brain from our sense organs, our eyes and ears, and presumably there's some special region then, in the brain, where these senses are processed like a central processing unit in a computer – decisions are made and then signals are fired out. Those signals are sent again in a one-way direction to our limbs telling them to move. Sensory neurons bring information in one way, motor neurons take instructions out the other way.

Yet no one has yet found this central processing unit in the brain, because that's simply not how the brain works. This has forced some neuroscientists to question this simplistic schema, which describes in a very mechanical way the relationship between brain, body, and environment. Their discoveries have uncovered precisely how important practical activity is for the human brain to know the world, and scientists are discovering there's a dialectical relationship between sensation and practice.

To take a simple example, how does the brain know that when we see a kaleidoscope of colours, of blues and greens, what we're actually seeing are the leaves of a tree against the blue sky? How is it possible to give the input of our sensory neurons meaning? How can we ground our sensations?

This is the subject of an interesting article in Scientific American, with the atrociously idealist title: ‘How the brain constructs the outside world’. It's by a Hungarian neuroscientist called György Buzsáki, and in this article he explains that the brain circuits are only able to ground incoming sensory information by taking some action.

So, Buzsáki uses the example of how a stick appears to bend when we see its reflection in water, but we know it's not actually a broken stick, by moving it around. If you hold a flower at arm’s length and behind it there is a tree that is 100 meters away and behind that, a mountain that's 10 kilometers away, to pure sensation they appear to be the same size. But we take an action in refocusing our eyes on the flower in the foreground, or reaching out and touching it, and that tells us it's in the foreground. Whilst when we move to the left and right, we see the tree moving against the background and that tells us that the tree is in the middle ground.

But neuroscientists like Buzsáki have made some very interesting discoveries that prove that it's not just sensory neurons involved in informing our brain. Our motor neurons, which are responsible for sending signals to take actions in some part of our body, have also been shown to send information back to our cerebral cortex in a loop, which they refer to as corollary discharge. And this corollary discharge helps inform the brain about the meaning of our senses.

A simple example of how it works can be demonstrated with your vision. If you look at something a few meters away and dart your eyes to the left and to the right, that thing you're looking at doesn't appear to move. But if you look at it again, close one eye and then press against your eyeball while you're looking at that thing, the world does appear to move. And this is because when you move your eyeball voluntarily, a signal is sent back to your brain; which tells you that the apparent motion of the image your brain receives isn't because the world is moving, it's because you're moving your eye.

But when your eye moves unexpectedly it appears that the world is moving. Voluntary action informs the brain, and it does it without you even having to be conscious of it. Conversely, the failure of our brain to correctly interpret this corollary discharge – this feedback from our motor neurons – is believed by some neuroscientists to be at the root of certain psychiatric disorders like schizophrenia. When our brain is unable to tell whether movement in the world is caused by our actions or by objective processes, the result is, naturally, quite distressing hallucinations. If the brain is unable to receive, encrypt, and correctly interpret information from the actions that we take, we're literally unable to comprehend the world around us.

These neuroscientists are not Marxists, but they are independently saying what Marxists have said, and what Marx said in his second thesis on Feuerbach. To know the world, more is necessary than simply to observe the world.

In the words of Marx, we must prove the ‘this-sidedness’ of our knowledge by taking some action. And for Marxists of course, Marxism is not just a nice set of ideas, but it's indissolubly linked with action, with the revolutionary struggle to change society.

Oliver: Two key trends in the theory of knowledge in the 20th century, although they seemed new and attractive, repeated many of the mistakes of the historical examples discussed.

The first of these trends is so-called pragmatism, which developed in the U.S. at the start of the last century. The central goal of pragmatism was to emphasise the usefulness of knowledge above all else: it's only worth knowing something if it's useful to do so. In this way, the personal applications of truth were raised above their objective validity.

The central question here, then, is what makes something useful? Pragmatism's only answer to this was to venture into empiricism. Usefulness, and therefore truth, wasn’t decided by what we can know about the objective world; it was decided by empirical and therefore subjective aspects of experience.

C. S. Peirce, one of the founders of pragmatism, claimed that what we mean by truth is simply what everyone agrees to be true. Now, it might be very useful for everyone to agree on things, but it really says nothing about the way the world actually is. And we have to be clear about where these subjective statements of usefulness really come from.

Ultimately, what's pragmatic for you is dictated by your class position. As Trotsky explains, a virtue for one class can be a sin for another. The socialist revolution for example, certainly wouldn't be very useful for the ruling class, and they certainly wouldn't all agree to it. But that says nothing about socialism's objective role in liberating the working class. If we want to have a genuinely scientific analysis, we cannot judge objective processes by subjective measures.

Another fundamental aspect of empiricism is that it stops its analysis at the surface level. The way things appear to us doesn't tell us all there is to know about their internal processes. We also have to analyse our experiences.

All empiricism, but particularly pragmatism, takes so-called ‘common sense’ as absolute law, and the shallowness of this analysis can lead to all kinds of errors. Without an understanding of logic to flesh out our analysis, all kinds of confused ideas can fill in the gaps.

William James, one of the founders of pragmatism, wrote a defense of the existence of God on the basis of his radical empiricism, and the key piece of evidence for this claim was that he interviewed people who had had religious experiences. Unsurprisingly these people were very enthusiastic about their religious experiences, and this was enough for a pragmatist to defend belief in God.

But empiricism is not the only route to subjectivism, dualism and confusion. Another key trend in 20th century philosophy was existentialism. And existentialism arrives at the flaws of pragmatism by the opposite route.

Existentialists like Jean-Paul Sartre and Simone de Beauvoir begin their philosophy by raising the subject out of their material circumstances. Sartre argued that the fundamental division in the world was between the ‘things that think’ and ‘things that do not think’. That is, between the ‘subject’ and the ‘object’.

His fundamental argument, which is generally shared by existentialists, is that the only thing that conditions consciousness is consciousness itself. Our beliefs are not reflections of our material situation, they are choices we make in response to it.

Sartre explicitly applies this to the question of class struggle. He says that no matter how bad the objective situation can get for the working class, these conditions cannot themselves bring about a revolutionary change in consciousness. The desire for a revolution is something the worker arrives at independent of their situation, as if by magic. He says that the objective conditions of poverty are completely divorced from the experience of poverty as ‘bad’.

So why do we think poverty is bad? The existentialist can only say that it's a choice. So this so-called radical freedom, is a freedom from the material world. It's a fetishising of the subject in general, and of the individual in particular. But by stripping us of an understanding of how we relate to the world around us, existentialism makes us impotent to change anything. If I can determine my own consciousness why not simply choose to enjoy poverty?

The anguish that the existentialists feel in response to our radical freedom, is in fact a nausea at their own class position. Petty-bourgeois academia can change nothing about the world. Cutting us off from the material world cannot serve to change it. This is true of both existentialism and pragmatism, despite their superficial differences. What we need is to understand the world in order to change it and ultimately it is only the method of Marxism that is able to do that.

Martin: Marx’s Theses on Feuerbach is one of the most important texts of Marxist philosophy. All the general lines of Marxist philosophy can be found in a condensed form in this short document, and you could probably elaborate on each one of the 11 theses for hours.

To make just a brief comment on the first one of the theses, Marx states in it: ‘The chief defect of all hitherto existing materialism is that the thing, reality, sensuousness, is conceived only in the form of the object or of contemplation, but not as sensuous human activity, practice, not subjectively. Hence, in contradistinction to materialism, the active site was developed abstractly by idealism. Which of course does not know real, sensuous activity as such.’

What Marx implies here is that dialectical materialism is something new, that overcomes the limitations of all previous forms of materialism. Materialism before Marx was contemplative and passive; it looked at the objective world seemingly from the outside, without being an active part of it. It either had a mechanical, one-sided conception, where the subject just passively receives the sense data from the objective world, as was the case in bourgeois materialism; or it just philosophised about the objective world without really asking what the relation between the objective world and the thinking and acting subject was, as was the case in ancient Greek materialism.

As Marx explains here, it was idealism that developed the active, subjective side of the relation between man and nature in general, and of the theory of knowledge in particular. More specifically, it was German idealism from Kant to Hegel, and it is exactly by integrating this active, subjective side into his philosophy that Marx was able to overcome the one-sidedness and the limitations of earlier forms of materialism.

In other words, in a seemingly paradoxical way, Marx is able to overcome the limitations of earlier materialism by directing a weapon against the weak side of materialism which was developed by the enemy camp, by idealism.

But there is a common misconception of this process in academic so-called Marxism, where we sometimes hear objections to our claim that Marxist philosophy is materialist, and therefore fundamentally opposed to idealism. Objections such as: ‘Marx doesn't just refute idealism’ are a mechanical view that is too one-sided.

We hear that, ‘Marxism integrates both materialism and idealism in a synthesis’, but this is a serious misconception of what Marx did and what Marxist philosophy is. Under the pretext of using dialectics, they try to fuse together idealism and materialism, but this has nothing to do with real dialectics. It's a typical petty-bourgeois way of thinking, to try to compromise between two hostile, antagonistic camps. For them, the fact that Marx overcame mechanical materialism with the help of dialectical idealism, means that Marxist philosophy somehow stands in between or above the traditional opposition of idealism and materialism.

This is very dangerous, as it leaves the door wide open for idealism; and in this epoch of capitalist decay, idealism is virtually everywhere. We need a rock-solid understanding of materialism to be able to fight against all the pressures from non-proletarian classes. Marx didn't adopt any idealism into his conception. By doing this, his new materialism didn’t become less materialist, it became more materialist. It actually for the first time became materialist in the full sense.

Men and their minds are part of nature, but they're not just a passive object, subjected entirely to their environment. They are interacting with their environment through labour. They actively transform their environment, and it is precisely in this active process of interaction with their objective environment that men gain knowledge of this environment and the inner workings of nature; not from mere passive contemplation.

We learn through our collective experience of manipulating our environment. We experience how the objective material world reacts to our actions, and with the accumulation of these experiences and observations, we can generalise and draw conclusions on the properties of matter and its inner relations. And these general relations in turn are then tested again in practice.

So this conception of the active and subjective side has nothing idealist about it. It's not just the activity of the mind, as for the idealists; instead we have real material humans, with flesh and blood. We are part of nature and act upon nature in order to satisfy our needs. All ideas and knowledge come out of this material process, and through this knowledge mankind progressively gains the capacities to subject the objective world of nature to its own conscious control.

In this way, for the first time consciousness and ideas are explained in a fully materialist way. So once again, there is not a single iota of idealism in Marxism, and we really have to get that right if we want to resist the pressures from alien classes, to be able to fight for socialism.

Adam: We are living in a material world and our own self is made up of matter. But the human body is capable of thinking and a whole thought process goes on in the mind of humans. These thoughts are not matter and we cannot touch our thoughts, or smell or hear the thoughts of others.

Some people say that thoughts are also matter, which is completely wrong. They try to explain the neurological workings of the brain and the chemical reactions by trying to prove that the thinking process is a material thing.

It is true that without a material body and neurological, physical structure, the brain is unable to produce thoughts. But even though the thought process ends with the life of the person, nonetheless the thinking process is not matter.

The whole history of philosophy, spread over centuries, has been a struggle to establish a relation between this thinking process produced in our human mind and the material world around us. Idealist philosophers would say that matter doesn't exist, while materialist philosophers before Marx would emphasize the role of sense experience and belittle or deny the role of mind.

In this process, philosophers have tried to discover the laws of this thinking process, and also the relation of the thinking process with the objective world. In the Marxist philosophy of dialectical materialism we find the solution to this riddle, and the correct relation between the thinking process and the material world is established.

In fact, Marx arrived at this conclusion through the critique of Hegel's philosophy. Hegel discovered the method of dialectics in which mediation between the subject or thinking mind and the objective world takes place. Hegel describes this whole process in great detail; in the beginning there lies an immediacy, or the moment when the process of mediation has yet to begin between the subject and the thing-in-itself.

According to Hegel, “The immediate existence of spirit, consciousness, contains the two moments of knowing and the objectivity negative to knowing”. In the same paragraph of the Phenomenology of Mind, he continues: “The science of this pathway is the science of the experience which consciousness goes through. The substance and its movement are viewed as the object of consciousness”.

Hegel explains in detail this whole process of appropriating the object. At the end of this process the ‘thing-in-itself’, mediating with the subjective mind becomes the ‘thing for itself’.

In his critique on Hegel's philosophy, Marx understood the limitations of Hegel due to his idealism. He pointed out those problems to the development of the dialectical method discovered by Hegel, from a materialist point of view. For Hegel, the objective world exists only as thought-entities or concepts.

Marx said, “The human character of nature and of the nature created by history, man’s products, appears in the form that they are products of abstract mind and as such, therefore, phases of mind, thought-entities”.

For Hegel, the subject is also called consciousness or self-consciousness, and the object is also called abstract consciousness. Marx said, “Just as entities, objects appear as thought-entities, so the subject is always consciousness or self-consciousness. Or rather the object appears only as abstract consciousness. Man only has self consciousness”.

Hegel, in the end of this process of mediation, puts forward the identity of subject and object, and this shows that the whole process of thinking or mediation was, for him, within the thinking mind and not between the mind and the material world.

Or, in the words of Marx, it was a dialectic of pure thought. To quote Marx again, “Just as in itself abstract consciousness (the form in which the object is conceived) is merely a moment of distinction of self-consciousness, what appears as the result of the movement is the identity of self-consciousness with consciousness – absolute knowledge – the movement of abstract thought no longer directed outwards but proceeding now only within its own self: that is to say, the dialectic of pure thought is the result.”

From Marx's point of view the complex relation between material reality and the concepts in the mind, doesn't take place only in thought, but in reality. Marx writes in the Theses on Feuerbach, “The question where objective truth can be attributed to human thinking is not a question of theory, but is a practical question.” For Marxists, unlike Hegel, complex phenomena like the state, political parties and revolution, do not exist only in thought but in reality, and are part of the material world.

The state that operates around us is undergoing tremendous changes under the hammer blow of events, and so do the concepts about the state in the minds of the people. These concepts have been developed over time with the collective experiences of people and also through rational insights into these phenomena over time.

During a strike, when the ruling class uses the full force of the state to break the strike of the workers, the concepts about the so-called benevolent state undergo profound changes. Concepts about various political parties have also been developed over a period of time. These parties in a given society can undergo significant changes in particular circumstances and so do the concepts in people’s minds about these parties – though this relation is not directly proportional and the thought process might sometimes lag behind the actual events.

But ultimately it is the material conditions that determine consciousness, and as Marx wrote in the Theses on Feuerbach, all social life is essentially practical. All mysteries which lead theory to mysticism find their rational solution in human practice and in the comprehension of practice. The philosophers have only interpreted the world in various ways. The point is to change it.

SUM UP

Daniel: Science has shed light on how the mind is an active participant in sensory and conscious experience. The mind applies abstractions and generalisations to experience to make sense of it and it's doing that all the time; but it doesn't just do that with conscious ideas. There's also an ongoing, unconscious process underneath that, filtering information in meaningful ways – which is a process that we share with many animals.

For example, scientists understand now that the mind is constantly filtering information out and concentrating only on key information. The mind essentially has what you could call algorithms, that allow it to predict what information it is going to receive, or rather what is going to happen around it. Otherwise we would be overwhelmed with unnecessary detail and so the mind says, “it's obvious what all the rest of the information is, I don't need to process that, I can guess what is there”.

This is the same principle behind compression – where files are compressed by computers and unnecessary, repetitive information is filtered out, and an algorithm is used to fill in the blanks.

For example, if you look at a blue sky, obviously there's a lot of blue space and the mind doesn't really need to process all of that information for every tiny little bit of blue light that hits the retina. So the mind guesses essentially that the sky continues to be blue.

This process is probably one of the main causes of hallucinations. For example, people who have lost their eyesight typically see things even though they don't have any eyesight. But what they see is obviously not real. For some reason they frequently see lots of small people moving around in their vision. If such people are very stressed or worried, frequently the images they see are of zombies and dead bodies. This is very unpleasant for them as you can guess. And it's thought that this is the result of the same process that predicts what fills in the blanks of our experience.

When we no longer receive visual sense data from the external world, that same tendency becomes unmoored – it goes off on its own tangent. Also, if you take hallucinogenic drugs it's thought that it's probably a similar thing that is happening; the patterns are a product of the mind being over active in its predictions.

This doesn't prove that our experience is subjective, because we're always predicting things and we're imposing onto our experience our own subjective ideas, if you like. What these hallucinations show is that we need constant input, real data from the external world, otherwise what we see frequently becomes nonsense.

The school of philosophy known as pragmatism is another form of subjective idealism from the 20th century. It says essentially that ideas have nothing to do with truth. We might think we're trying to say something about the external world but that's not really what ideas are about. All that ideas really say and all that they're capable of saying is this thing works and is useful, and therefore that's why we have that idea. The materialist answer to that is obvious: what determines that something is useful and what determines that something else is not useful? Of course, it is objective reality and our particular relation to it as objective material beings.

Another key point to consider is the redundancy of subjective idealism. When people first learn that such a school of thought exists, they often find it absolutely laughable. They say to anybody who subscribes to that school of thought: “well why don't you just run out into the road then and wait to get run over since it's all just a figment of your imagination?”

Of course, no subjective idealist actually applies the ideas in that way – they live their lives just as if it were not in any way true. They continue to eat food, they continue to look before they cross the road, etc.

They will say, in response to that, that you're missing the point: the point of this philosophy is that it's not a practical thing, it's just a theoretical insight. Subscribing to it doesn't oblige you to make any changes about how you live your life. This is an admission that it's a redundant philosophy, a dead end. And Hegel said the following about sceptics, “if anyone actually desires to be a sceptic, he cannot be convinced, any more than he who is paralyzed in his limbs can be made to stand. Scepticism is, in fact, such paralysis, an incapacity for truth which can only reach certainty of self.”

As Marx said, it is a scholastic question, it's not a practical or relevant question. However, I do think it is possible to disprove subjective idealism even from within their own arguments, and the clue is in their own admission that their philosophy makes no practical difference to their lives. Some subjective idealists have ended up finding that, in order to explain what subjective experience is, they need to make use of the idea of an objective world, independent of our own minds.

For example, Fichte, the German subjective idealist, said that everything is just your own ego and the world around you is a projection of your ego. But then he had to explain why it is that this ego that creates reality for itself constantly surprises itself with the experiences that it has. In other words, each thinking person obviously does not feel as if they have complete and total control of the world around them, and the world around them does things that they do not expect it to do. This is obviously a fundamental aspect of human experience that any philosophy should be able to explain.

Fichte’s explanation of it is that the mind, or ego, divides itself and that there is a part of the ego which presents experiences to the subjective ego or the inner ego, therefore giving the appearance of not having control over our surroundings.

The empirio-critics that Lenin attacked did the same thing. For example, Bogdanov made a distinction in his theory between the sense experiences that are dependent upon the nervous system and the sense experiences that are not. In other words, everything is just sense experience, there's nothing beyond sense experience; but within sense experience there's a difference between those sense experiences about oneself, and those that are about the apparently external world. This is an admission that they need the category of objectivity in their own philosophical systems, in order to make any sense of how things really seem to us.

What we have is a philosophy which adds and changes absolutely nothing about how we actually live our lives and the ideas that we use on a day-to-day level. And even within its own, purely scholastic system, it reintroduces the basic ideas of materialism in the sense of an independent objective world, but it says that it is still part of subjective experience and is dependent upon the subject.

It's a convoluted system, tying itself in knots to end up explaining nothing and presenting to us a picture of reality which is merely a confused way of telling us what we already know. But in the process of doing so, rather than helping us to understand how we actually develop the ideas that we have, it estranges us from that process. It presents all of our typical ideas about experience, but in a subjective idealist packaging.

What we need is a philosophy that does not estrange us from our own consciousness and the way that we live our lives, nor one that has a complete and fundamental chasm between the philosophy itself and the actual life that you lead. We need to study consciousness the way that it really is and instead of just doubting the ability to know anything, we need to move beyond that and say, well how is it that we know things?

Once again, if these ideas are so redundant and so ridiculous, why on earth do they exist? What role does this trend play?

Well first of all it is a faithful expression of the strange social position of the petty-bourgeois academic and in many ways, the outlook of the bourgeois class in general, for whom the external world and society is really ultimately baffling. They're impotent to do anything about it, and they're unable to connect their ideals about the world, how the world ought to be, to their practice, and how the world actually is.

Even the richest, most powerful capitalist in the world is incapable of changing the laws of capitalism and preventing economic crises. And therefore that class has produced a philosophy that essentially says it's impossible to know what the external world is and all you are is a lone person on your island.

But this ridiculous philosophy hangs around also because it serves another useful purpose: it helps to spread a general cynicism and pessimism about the world. We can see that very clearly with the influence that postmodernism has had on left-wing intellectuals and left-wing students who probably do want to change the world or start out wanting to change the world.

It teaches them that the height of sophistication is to doubt everything, to see the world as impossible to change, and to understand and to see anybody that has practical answers to the problems of the world as very naive and simple. In the same way, the ordinary person who assumes that they understand the world around them is without any theoretical knowledge and is seen as a rather naive person.

It ends up giving these people a haughty kind of contempt for ordinary people and the fact that they believe the world around them actually exists, and then in that way it destroys their confidence in the ability of ordinary people to change society.

So long as we live in a society of profound inequality – and perhaps more importantly a society of uncertainty, of lack of control – and so long as humanity finds itself subject to the fate of capitalist crisis, with no control or understanding of that crisis, then this kind of sceptical mentality will continue to dominate amongst the mainstream intellectuals.

This philosophy is an expression of the bourgeois class’ inability to understand its own system and inability to solve humanity's problems. In the end, the only way that we can do away with this philosophy is not through discussions like this, as important as they are for us. It is through, as Marx said, revolutionary practice. That is to say, utterly transforming the society in which we live into a society in which ordinary people genuinely control their own fate. And when that happens, all of the scepticism, the cynicism, the conspiracy theories – all of that kind of mentality, and that deep insecurity, will begin to wither away.

To solve the problem of subjective idealism, we need not so much to defeat it in arguments, but to defeat it in practice; and that's why it's so important to get involved in the fight to change society.