This is a series working from the Penguin edition of Aristotle’s Metaphysics, translated by Hugh Lawson-Tancred.
Having arrived at the aim of metaphysics, that is, to ascertain the principles and causes from which the world comes, Aristotle spends a few chapters recalling how philosophy before him has approached the question. He begins chapter three by pointing the reader to the four kinds of causes he discussed in detail in Physics. The actual text does not give much information because Aristotle doesn’t have anything to add to what he has written elsewhere. The translator’s introduction to the chapter is helpful though: a thing causes another thing in four ways, “by providing the form that it realizes, by being the matter from which it is made, by being the source of the process that leads to its coming to be or by being that for the sake of which the thing is produced” (11). These may not be four kinds of cause as much as they are four ways of explaining cause.
The early philosophers ascribed cause to material things such as water, air, or fire. Some favoured a single principle while others ascribed cause to multiple, even infinite sources. But matter could not explain everything. Thus some went further and pointed to a mind or love/desire beyond matter as something that organised the world and/or gave it purpose. To explain the source of bad things, strife (which Aristotle does not really explain) was sometimes posited as a cause that worked in dialectic with love. However, many of these ideas were not adequately clarified by the philosophers and poets who suggested them, nor applied consistently in their thought.
In chapter five Aristotle recalls how the Pythagoreans with their love of number managed to see number as elementary for all things. One, in turn, was elementary for all number. Many philosophers were also monists (those that believed existence or reality is one). Aristotle distinguishes two monists, those who accepted a doctrine of movement and those who denied that change is possible. In chapter six he goes on to examine the origin of Plato’s Theory of Forms, that is, that there is a real world of abstract Forms of Ideas beyond that of perception. Aristotle sees Heraclitus’ scepticism towards the reliability of the senses and Socrates’ search for universals in his ethical philosophy as the key influences acting upon Plato’s thought here. In Plato’s philosophy, it is the Forms which are the causes or principles of things.
In chapter seven Aristotle contends that none of the many philosophers briefly surveyed went beyond the four causes he outlined in Physics. “[R]ather, all seem to be indistinctly grappling after these” (26). While most philosophers attributed cause to matter, only a few posited something extra-material like mind or love, which is the source of change. Aristotle maintains that none of them posited teleological causes, that is, the causes which give things their purpose.