Marxist philosophy of nature
There is no specific Marxist philosophy of nature as Karl Marx did not conceive of nature as separate from society. As the young Marx exposed in the "Economic and Philosophical Manuscripts of 1844", labour transforms nature which becomes the "inorganic body" of man. In the same way, Marx's theory of human nature ("Gattungswesen") opposed the traditional conception of an eternal human nature which remained the same in all places and times. Later, Friedrich Engels wrote the "Dialectics of Nature" (1883) in opposition to German "Naturphilosophie". Marx and Engels' thought was then codified into "dialectical materialism  which is what is usually referred to when speaking of a Marxist philosophy of nature". Such a doctrine was rejected by several Marxist philosophers, starting with Georg Lukács and Walter Benjamin. Basic overview. The basic Marxist idea is that everything can be explained by one thing—matter. Matter is the total explanation for space, nature, man, consciousness, human intelligence and every other aspect of existence. Marxism then assigns the task of knowing all truth to science. If science can get to know everything about matter, then it can get to know about everything. Conclusively, matter is accepted as the beginning  and ending of all reality. Taking the concept of matter, Marxism then sets forth to answer three questions: What is the origin of energy or motion in nature? What causes galaxies, Solar System, planets, animals and all kingdoms of nature to constantly increase their numerical quantity? What is the origin of life, the origin of species and the origin of consciousness and mind? Marx and Engels answer all of these questions with three laws. The law of opposites, the law of negation and the law of transformation. Law of opposites. Marx and Engels first started with the observation that everything  in existence is a combination or unity of opposites. For example, electricity is characterized by a positive and negative charge and atoms consist of protons and electrons which are unified but are ultimately contradictory forces. Even humans through introspection find that they are a unity of opposite qualities. Masculinity and femininity, selfishness and altruism, humbleness and pride, etc. The Marxist conclusion being that everything "contains two mutually incompatible and exclusive but nevertheless equally essential and indispensable parts or aspects."¹ The basic concept being that this unity of opposites in nature is the thing that makes each entity auto-dynamic  and provides this constant motivation for movement and change. This idea was borrowed from Hegel who said: "Contradiction in nature is the root of all motion and of all life." Law of negation. The law of negation was created to account for the tendency in nature to constantly increase the numerical quantity of all things. Marx and Engels decided that each entity tends to negate itself in order to reproduce itself in higher quantity. Engels often cited the case of the barley seed which, in its natural state, germinates and out of its own death or negation produces a plant . The plant in turn grows to maturity and is itself negated after bearing many barley seeds. Thus, all nature is constantly expanding through dying. The elements of opposition which produce conflict in each thing and give it motion also tend to negate the thing itself; but out of this dynamic process of dying the energy is released to expand and produce many more entities of the same kind.³ Law of transformation. This law states that a continuous quantitive development by a particular class often results in a leap in nature whereby a completely new form or entity is produced. This  theory draws many parallels to the theory of Evolution. The Marxist philosophers concluded that matter is not only auto-dynamic and inclined to increase itself numerically, but through quantitative accumulations it is also inherently capable of "leaps" to new forms and levels of reality. Marx and Engels saw these laws as the discovery of the greatest mystery of all: What is life? Origin of life. On the basis of these principles the Marxist philosophers decided that the phenomenon of life was the product of one of these leaps. Engels stated that the complex chemical structure of matter evolved until albuminous  substance was formed, and from this substance life emerged. He insisted that just as you cannot have matter without motion, so also you cannot have albumin without life. It is an inherent characteristic of albumin, a higher form of motion in nature. He also suggested that as soon as life emerged it would gradually grow in complexity. Consistent with evolutionary theories of punctuated equilibrium, Marxists believe that new forms in nature are not the result of gradual change but that quantitative multiplication gradually builds up momentum for a "leap" in nature which produces a change or a new  species. They believe that incidental to one of these leaps (and leap may be regarded as a set of genetic mutations) the phenomenon of consciousness emerged. The creature became aware of the forces which were playing on it. Then at an even higher level another form of life appeared with the capacity to work with these impressions and to arrange them in associations. Thus mind evolved as an intelligent, self-knowing, self-determining quality in matter. However, matter is primary and mind is secondary. Therefore, there can be no soul and no God. They believe that everything in existence came  as a result of objective tendencies (i.e. movement, negation, etc.) inherent in nature. There is no law, or design, or God. Only matter and force in nature. As for man, he is an accident like all other forms of life except he had the good fortune to possess the highest intelligence in existence. This is said to make man the real god of himself and the universe. Opposing views. Marxist philosophy of nature has been scrutinized greatly. Opponents of dialectical materialism point out a number of fallacies. They point out that the Law of Opposites is intended to explain the  origin of motion, but two contradictory elements would never come together in the first place unless they already had energy in themselves. Contradictory forces in nature are found to have energy independent of each other, bringing them together simply unifies motion or energy already in existence. Therefore, opponents point out that the Law of Opposites does not explain motion but presupposes it. The Law of Negation is critiqued as only describing a process of nature. Not only that, but the law doesn't take into account that its negation may be unrelated to its reproduction, and that it may reproduce  many times or not at all before it negates. Opposition also point to the Law of Transformation as merely describing a process in nature without accounting for it. They claim that the possibility of a series of accidents leading to something as complex as the eye, circulatory system or other parts of the body and then making them work in perfect unison are extremely low. Such an argument bears similarities to irreducible complexity, a common argument against evolution.