The principal question of philosophy is that of the integrity of the World. This means that there is only one philosophy, and all philosophers contribute to the demonstration of that integrity by their works. Under certain economic and social conditions, however, the distinctions between different philosophical schools may grow into the controversy of opposite ideological camps commonly known as materialism and idealism. This controversy manifests itself in a variety of forms depending on the subject of consideration. One of the sharpest distinctions between the two philosophical parties can be drawn in treating consciousness and related problems. Three aspects of the same question are:
Materialism and idealism differently cope with these questions. Since both are only partial representatives of philosophy as such, there are faults in the argument of both materialists and idealists; however, materialism seems more preferable as a methodological basis for science.
For materialism, the World is something on itself, and it does not need consciousness to exist. Consciousness is nothing but one of the forms of the world's existence. In classical philosophy, the World as it is without any reference to consciousness and observation was called Matter. Later, materialists felt the incompleteness of metaphysical (vulgar) materialism and, being unaware of higher-level, dialectical materialism, tried to avoid that definite categories, talking about "Nature", "Mind-independent reality" etc.; quite often such a term substitution meant a concession to idealism, and hence eclecticism.
Idealism treats the World as an Idea, without too much concern about what this word could mean – generally, ideas have something to do with mental forms abstracted from what is being thought of in them. For subjective idealism, ideas belong to an individual mind, while objective idealism admits existence of ideas outside individuals; in the latter case, the necessity to distinguish an objectively existing idea from Matter demands the existence of a "supreme" conscious being, God.
The main problem with idealism is that it is intrinsically incompatible with common binary logic, producing paradoxes and contradictions that serve fine to give a touch of profundity to a work of art, but cause much inconvenience for an idealistic-minded scientist. Thus, an idealist has to admit the existence of at least one mind that could produce ideas; otherwise, ideas would have nothing "ideal" about them, coinciding with what materialists call Matter. In fact, consistent idealism implies the existence of only one mind (either personal or impersonal), with all the other minds being only ideas produced by that unique mind. However, postulating the existence of that universal mind little differs from postulating the diversity of material things – and the very distinction between idealism and materialism gets lost. This is like a person saying "I am wrong" can be told neither wrong nor right, from the logical standpoint. Likewise, an idealist saying "I am dreaming, and all I experience is nothing but a dream" can always be asked: "Do you exist at all?"
Certainly, the logic of scientific research can in no way be reduced to binary discrimination; still, the same inconsistency can be traced anywhere in idealistic methodology of science. It is necessary to admit existence of something to tell anything – otherwise, any discussion is pointless.
An idealist can never be consistent, or they would have to keep their thoughts in themselves without any need of arguing for them. Indeed, why should one talk to one's own fantasy? If all I experience is only a dream, why should I try to strive for or struggle against anything? And is there any need to work to get one's daily piece of bread? Class roots of idealism thus become evident: one has to be wealthy enough to abandon worrying about earthly things... On the other hand, this may result in more mental lability, and many problems could be much easier formulated by idealists, despite all their inability to resolve them.
The impossibility of consistent idealism results in that "pure" idealist could only be known in psychiatry rather than philosophy. One has always to deal with an eclectic mixture of materialist and idealist views, and a particular person can often adopt an idealist stand in one or two problem, remaining materialistic in most others. All idealists use to eat and drink, breathe air and live somewhere. Surely, they can call all that mere imagination, provided they are not robbed of it.
The intuitive resistance to materialism one can sometimes feel is mainly due to the essential openness of that doctrine. Thus, there can be no grounds for the existence of the world as Matter, and no logic can be decisive in determining the validity of any statement. One has always appeal to "out there", being ready for more surprises to come with new experience. One cannot "derive" the world from a single idea, as many idealists are apt to. This inevitability of changing paradigms is compatible with the actual development of science – but, on the other hand, it may produce the impression of too much randomness in materialistic science. Merely postulating Matter is not enough to express the integrity of the World.
Nevertheless, materialism has a merit of inherent consistency, which makes it more suited for scientific research. It gives one right to speak of things as they are, so that one could discover the laws of their motion rather than invent them. However, methodological power of metaphysical materialism is limited, since it cannot comprehend the mutual penetration of "discovering" and "inventing" in the history of science. It is in dialectical materialism only that the people's ability to change the world has become as important as their ability to reflect it.
Assuming the priority of Matter above consciousness, materialism poses the question about the difference of consciousness from Matter, and its origin. This becomes a starting point for studying consciousness, including scientific study. Idealism cannot speak of any research at all, and especially of studying consciousness, since there is nothing else to what it could be related and thus acquire definiteness. The origin of consciousness caused difficulties for metaphysical materialism too, since it could not reduce consciousness to any of the other known forms of motion in Matter. It is in dialectical materialism only that the social nature of consciousness has been discovered, and it became possible to study consciousness in its specificity rather than mere physical of physiological phenomena accompanying conscious activity.
The correspondence between people's thoughts and the World on itself has always been one of the hardest problems in philosophy. A materialist proclaiming the World's existence unrelated to any cognition has to explain, how it comes that people can think about the World in the forms that agree with the forms of motion inherent in Matter. Also, one has to understand why people can invent abstractions that seem to correspond to no reality at all.
For an idealist, the answer is quite simple: the only reality is that invented by the mind, and no correspondence to anything is required. This position is most convenient for an artist, but it encounters difficulties when it comes to science. Indeed, why should there be any need in scientific research at all, if anything one mentally invents would equally do? Why should one prefer certain mental forms and reject others? There is no need in scientific community and the norms of presentation consistency, etc. As a reaction to the rigid institutionalized forms of science in an underdeveloped society, this may be a useful line of thought, preventing too much dogmatism. However, its exaggeration results in abstract relativism denying the possibility of knowledge as such.
If ideas are considered as prior to Matter, all one can experience is one's own imaginations. An idealist cannot even raise an objection against materialism since that objection could be formulated in materialistic manner only, as an assertion about the relatedness of people's thoughts to something different from them. Consequently, there can be no idealistic epistemology, like there is no room for idealistic ontology – philosophical idealism can only exist owing to its inconsistency.
Metaphysical materialism was much criticized for inconsistency too, since it gave no explanation of how material things and their motion get represented in the mind, and how the "boundary" between the already known part of the World and yet unknown World gets "transcended". It was argued that, since we can think of anything only in terms of our mental forms, and we can tell nothing about what is not involved in our activity; hence all we can know is "mind-dependent", and there is no need to assume any "mind-independent reality" at all. Various eclectic philosophies appeared in that way (dualism, skepticism etc.). However, in consistent (dialectical) materialism, there is no confusion of mental forms with material things or processes, and one can consider the origin of mental forms like the origin of any other things, thus establishing correspondence between mental forms and phenomena they reflect. Moreover, mental forms become culture-dependent in this approach, and one can study the history of ideas rather than passively register them.
Metaphysical materialism tried to avoid the problem of the origin of mental forms, at most reducing them to physiology of the brain. Since consciousness is not a biological phenomenon, such a reduction is bound to fail, which often served to strengthen the position of idealism against that of vulgar materialism. However, considering consciousness as a social phenomenon, dialectical materialism could easily relate mental activity to material activity, thus demonstrating that mental forms are nothing but schemes of activity formed in economic and social development depending on quite material factors. The materialistic assertion that people's thoughts agree with what actually occurs in the World has been augmented with the observation that the formation of consciousness is a social process, and the society is a material system organized so as to ensure the adequacy of mental forms thus produced to the forms of Matter reflected. On the other hand, clear distinction of material and mental forms, which is impossible in idealism, gives grounds for historical consideration and explains why people fail to implement their ideas, and how ideas can ripen for implementation with the development of economy.
The existence of abstract ideas that do not reflect anything in the world has always been a weak place of vulgar materialism, while being an immediate consequence of idealism. However, idealism cannot give any explanation too, since abstract thought gets identified in it with random thinking, without any principal difference from delirium. Dialectical materialism explains the obviously non-random organization of abstract thought relating it to cultural rather than material processes, so that any abstract idea would reflect certain social phenomena and be culture-dependent, which provides the basis for scientific study in logic. In particular, idealism and materialism themselves are supposed to ideologically reflect the life of certain social groups.
One more aspect of reflecting the World in consciousness is that of communicating one's experiences. This is the problem that cannot arise in consistent idealism at all, since there is only one mind, and it has nobody to communicate with. For vulgar materialism, one can communicate the "objective" content of one's mind, but can never convey how it feels like to experience it. When the development of consciousness becomes related to the development of society as a part of Nature, as in dialectical materialism, the problems gets easily resolved: since the appearance of any conscious experience is a social process, the others will always be ready to reproduce that very experience in their minds and feel it exactly like it feels for anybody else. Universal communicability is a fundamental property of consciousness, and it is deviations from this rule that have to be specially considered. One cannot consciously feel what cannot be consciously felt by another person, and the level of the development of consciousness is determined by both comprehending the World and being able to communicate that comprehension.
The fundamental principle that demands practical implementation for any idea as the final criterion of its validity has been introduced in philosophy by dialectical materialism, which stresses that people do not merely reflect the World, but also re-design it to satisfy their needs. As a result, there appears a "second", human-made world that could be called Culture. Though Culture is certainly a part of the World, it is different the rest of it in that it has been formed by conscious beings, being reflected by them as such.
Old materialists could not see the all-penetrating influence of culture on people's experiences. The priority of Matter was understood in a one-sided manner, and all the movements of human mind had to be interpreted as immediate manifestations of something material. On the contrary, idealism could see the cultural side of people's experiences only, without being aware of the more fundamental, material side; as a result, the very experience of culture became distorted, being robbed of its material component.
Belief in the absolute power of ideas is a common delusion of idealism: if something is in consciousness, it is real. This reveals the social roots of idealism: if one is accustomed to that a thought about $100 at one's disposal quite often agrees with the actual disposability of that (or greater) sum, such person can easily get used to thinking about thoughts as the source of any reality at all. Thus, the fantasies of the mind may acquire the same importance as external activity, and abstractions may be taken for the only knowledge possible.
A materialist has to admit that there is something one cannot do, if there are no material conditions for that. People's freedom is limited by what they are able to do. However, vulgar materialism considers only physical or physiological ability, while dialectic materialism also takes social conditions into account. One cannot have breakfast for $100 if one does not have $100 in one's disposal – and one cannot have breakfast for $100 if there is nobody to perceive a 100-dollar bill as money. [*] The same holds for consciousness and thought. No idea can be implemented if the society is not ready for that; moreover, no idea can come to anybody without the society providing the conditions for its appearance.
Nevertheless, materialism is much less restrictive than idealism in that respect. In fact, the only freedom allowed by idealism is the freedom of fantasy, dream, imagination – while materialism also allows one to actually change the World, albeit within certain limits. In dialectical materialism, conscious beings are treated as able to purposefully change every side of reality, including their selves as its part. That is, the very abilities of the people can be infinitely extended, and, virtually, there is nothing in the World that could not be changed – in reality, not in the dreams. There will be ever larger domain of Culture in the World, and it is the supreme sense of human existence, to cultivate the World, thus making it a unity. Materialistic philosophy grows into practice, the only possible way for consciousness to exist.
Art, science and philosophy are different levels of creativity, and neither of them can be reduced to or exist without the others. The syncretic nature of art makes it susceptible to idealistic ideas, while the analyticity of science makes it be essentially based on materialism. Philosophy has to absorb the features of both art and science, melting them into a unity of a different kind. Still, philosophy cannot reveal the sense and value of materialism or idealism within itself, since it is only practice that gives the final answers.
There is only one philosophy, and a philosopher can be said to act as a philosopher only while revealing some aspects of the integrity of the World. The opposition of materialism and idealism entirely belongs to the level of socio-economic development known as civilization, that came to replace the primitive communal system and has to eventually give way to a different organization of economy and society. When there will no social antagonisms, no ideological controversy will be possible, and the unity of philosophy will be restored, on a higher level. However, this will not be an eclectic mixture of materialistic and idealistic elements – it is the reasonable core of the both that must survive. That is, the productive force and consistency of the materialistic view will be complemented with a clear view of ideality as an attribute of any material existence characterizing it as a possible experience and a possible product of conscious activity.