Aristotle (384 - 322 B.C.)
Known as “The Philosopher”
Aristotle was a student at Plato’s Academy
Aristotle was not satisfied with Plato’s solution of the problem of being and becoming. It was dualistic, and he sought to solve that problem.
He wanted a unified theory  of knowledge that would incorporate all of the sciences without any leftover dualism.
He left the Academy and later founded his own school in Athens, the Lyceum
He presided over the Lyceum for 13 years, involved in scientific studies and in writing.
Aristotle also had a famous student -  Alexander the Great.
From Aristotle he gained a passion for unity. This was the basis for his quest to unify the regional cultures by a common language.
All individual entities (everything that exists) exists as primary substance.

The things in this world, according to Aristotle, are real and they are substantial. (Contrast this with Plato’s view.)
Matter and Form
Sometimes called the “theory of form.”
Being AND becoming are found in each individual entity. Each substance contains both matter and form.
Form is that which gives its subject its being. Without participating in being, or without containing being, whatever is, couldn’t be, so you couldn’t be, so you couldn’t have any real things.
Also, things in this world (physical) have elements of change (becoming) and that is part of the matter of a thing.
The form is the eternal being, and the matter is the part that is changing and is the locus of potential.
Actuality v. Potentiality

Actuality is a characteristic of form (being).
The form moves or directs the particular object towards its potential. The form determines its potential.
Explanation. An acorn contains within it the form of oak tree. This is what directs it toward its actualization of oak treeness. This is why acorns never turn into elephants.
An acorn is a potential oak tree, but not a potential elephant.
Substance and Accidens
Every physical object has substance (matter and form) AND accidens.
Accidens are the external, perceivable attributes of an object.
Example: Chalk has the accidens of whiteness and cylindricalness.

Aristotle argued that the substance and the accidens were always copresent.
For Aristotle, it would be impossible for pure matter to exist, because it would be pure becoming, so it wouldn’t really exist.
Aristotle’s concept of God.
While pure becoming (pure potential) is impossible, pure being (pure form, or pure actuality) can exist. Furthermore, if there is anything at all (and clearly there is), then there MUST be pure actuality.
Aristotle’s concept of God is pure form - actuality without potentiality.

God = “The unmoved mover” or the “uncaused cause.”
The formal first cause of everything that exists in the world.
How does it all fit together? How is the problem of the one and the many solved?
Eternal Being: The power to organize and generate and move everything. The ultimate source of all motion is pure form.
How does the unmoved mover do it? The Pure Form is not itself moving. It moves everything by attraction. The analogy is the moth and the flame. The flame attracts the moth. Other similar ideas might be magnetism or gravity.
Aristotle’s god is not personal, but a force or power. This being is eternal and exists by necessity. There is no concept of voluntary creation, consciousness, etc.

Aristotle’s Epistemology
How do we know what we know?

Aristotle’s epistemology is a posteriori. We learn through sense perception. There is an image in our minds, and from these images come ideas. The mind does have a priori abilities (the ability to work with the raw data of images to combine them into intelligible ideas).
Realism v Nominalism
(Recall that Plato was both a realist and an idealist.)

For Aristotle, ideas are not real in the sense that they have being.
Res (thing) noumina (name): Ideas are names we give things.
Nominalism: Universals are not things, but names.
Universal concepts are merely mental names conceived by the mind.
Truth = conformity of the mind and the thing.
When your mental idea corresponds to the external object that you are seeking to know, then you have truth.
There are certain principles of knowing that are common to all fields of inquiry for science to be possible. So he talked about the role of logic.
He did not view logic as separate from other sciences, but the organon of all sciences.
(organon = instrument)
The instrument we need in order to construct real knowledge is logic. Logic is a necessary instrument for all intelligible discourse.
Logic (Aristotelian Logic)
Aristotle laid the foundation of formal logic.
Our statements must be logically constructed. They must not violate the first law of logic: The law of non-contradition.
Logic and all science depend upon the relationships between the general and the particular. (subject and predicate).

Example: A horse is an animal.

The process of classification.
Similarities and differences
Humans are in the animal kingdom, but we’re not baboons.
More and more precision until they have a name, height, etc.
Logic requires that these can’t be brought into irreconcilable opposition to each other.

The law of non-contradiction: A cannot be A and non-A at the same time and in the same relationship.
That which is illogical represents chaos, not cosmos. And absolute chaos cannot be known in an orderly way, making knowledge or scientia a manifest impossibility.

Logic itself has no material content and in this regard may be seen as a formal science, much like mathematics.
Logic measures or analyzes the relationships of statements or propositions. It can show that the conclusion of a syllogism is valid or invalid. It does not determine the truth of a conclusion or argument.

Arguments are not true or false, but valid or invalid.
Statements may be either true or false, but the logical relationship of one statement to another is either valid or invalid.
Aristotle wrote about the fundamental laws of logic, including the law of noncontradiction: Something cannot be what it is and not be what it is at the same time and in the same sense or relationship.
Aristotle was concerned not only about our thinking about things but also about the existence of the things we think about.
He finally rejected Plato’s philosophy, but he was still very much concerned about the relationship between thought and reality.

He argued that logic and truth were inseparably related. The laws of logic apply to all sciences because they are valid for all reality.

This is not to say that all that is rational is real. We can conceive of ideas that are logical but do not correspond to reality (unicorns, for example).

Everything that is real, however, is rational. The illogical cannot exist in reality. (eg// square circles.)

For Aristotle, the law of noncontradiction is not merely a law of thought, but also a law of being. Indeed, it is a law of thought precisely because it is first a law of being.
The Four Causes
Aristotle positied four distinct types of causes that produce changes in things.
1. The Formal Cause, which determines what a thing is
2. The Material Cause, that out of which a thing is made.
3. The Efficient Cause, that by which a thing is made, and
4. The Final Cause, that for which a thing is made, or its purpose.

Formal Cause: The sculpture’s idea or plan for a sculpture.
Material Cause: The block of marble.
Efficient Cause: The sculpture.
Final Cause: The decoration of a garden.
Notice that this is all teleological. Nature is also teleological. Everything is FOR something.
The ethics of virtue and the ethics of right action.
Aristotle asks, “What is the good man?” “The good man is an activity of the soul in conformity to virtue.”

A virtue is a mean between two vices.
Example: Courage is a virtue between cowardice and folly.
While it is possible to discuss particular virtues, like courage, honesty, etc., one cannot be virtuous unless they are virtuous in all areas.