Plato + Aristotle.

What is Heraclitus' challenge and how do Plato and Aristotle respond?

-Heraclitus was an ancient Greek philosopher who cast doubt on the possibility of gaining knowledge.

-He famously said “a man never steps into the same river twice”. This is because both the man and the river change.

-The world is in a state of ‘flux’ (change). So the moment we know something, it has changed.

-So how do we get knowledge? Both Plato and Aristotle are trying to answer this challenge.

What is Plato’s rationalist response to Heraclitus’ challenge?

-Rationalism is the epistemological theory that knowledge can only be gained a priori, not from experience.

-Plato’s cave illustrates his rationalism and his theory of forms.

-Prisoners are trapped in a cave all their life. They think shadows they see on the wall are the real world. One day a prisoner escapes (philosopher) and sees the actual real world.

-So we think the world we see is the real world, but it isn’t (that’s why we can’t gain knowledge from experience).

-The true world is the world of forms.

-The forms are perfect, eternal and unchanging forms of the everyday things we experience. What we experience are imperfect versions/representations of the real form those things partake in.

-E.g. if we look at a beautiful sunset, we are looking at the form of beauty, but because our minds are trapped in ignorance, we see a particular imperfectly beautiful thing that will change.

-Plato is accepting Heraclitus’ issue that we can’t gain knowledge from experience, but is proposing another method – pure a priori reason.

How can Plato’s theory of forms be criticised?

-There is no empirical evidence for the forms. However, Plato wouldn’t think this is a criticism.

-He thinks evidence from experience is just shadows on the wall of the cave. So Plato thinks it’s good there is no evidence for the forms!

-To really criticise Plato, we must show that he’s wrong to discount evidence.

-Aristotle has a better upgraded critique of Plato – He says we can gain knowledge from experience/evidence – through studying the causal processes responsible for the change/flux we observe.

-Aristotle argues this makes the theory of forms an unnecessary hypothesis – we can explain the world without them.

Is Aristotle's approach stronger than Plato’s?

-Aristotle’s approach is successful because it led to modern science.

-The prisoners in Plato’s cave observing illusions might work against Aristotle’s early version of the scientific method which only involved observation.

-Modern science combines observation with experiment. This has allowed us to control, transform and predict the world. This active dynamic relationship with experience cannot be reduced to prisoners passively observing shadows.

-So, the success of modern science escapes Plato’s critique & Plato is wrong to disregard the value of evidence.

What is Plato’s view of the Form of the Good and the hierarchy of forms?

-Part of Plato’s rationalism and view of reality is the theory of forms, which includes a hierarchy in it.

-The form of the good is illustrated by Plato in the analogy of the cave by the sun. It is the first thing the escaped prisoner (philosopher) sees.

-The form of the good is like the sun in that it allows us to know the world of the forms and is responsible for all the existence of the other forms. This makes it the highest form.

-Anyone who understands the form of the good becomes a morally perfect person – it makes it impossible for you to do wrong and so a philosopher with this understanding should be called a ‘philosopher king’.

-Below the form of the good are the higher forms like justice and beauty. Below those are perfect mathematical forms. Below those are the forms of the things we see in our experience, e.g. the form of tableness.

How do Aristotle and Nietzsche challenge Plato’s Form of the Good?

-Furthermore, Aristotle adds that there cannot be one unified form of the good which captures all the diverse and contextual forms of goodness in this world. E.g. in military strategy ‘good’ is efficiently killing people. But, in medicine ‘good’ is efficiently keeping people alive.

-Aristotle points out that being a good person, i.e., being virtuous, is required to do good, not merely knowing what goodness is.

-Plato is being too optimistic or just inventing the form of the good because he wanted philosophers to rule society.

-Nietzsche called the form of the good a ‘dangerous error’ and claimed philosophers tend to invent ideas to justify their emotional prejudices, such as a desire for power.

Why are Aristotle & Nietzsche’s criticisms effective against Plato’s rationalism?

-Nietzsche has a point that human reason is susceptible to influence from our desires. Hume argued similarly, that reason is a ‘slave’ of the passions.

-Plato’s rationalism is based on an overly-optimistic view of human reason, that it could in principle break free of influence from our desires. The clearest evidence for this point against Plato is that a morally perfect person has never been observed in history. So Plato’s form of the good is unrealistic.

-Plato tried to dismiss empiricism as invalid due to its potential to be mistaken, however he has overlooked that reason alone can also be mistaken and even corrupted.

-Nietzsche’s suspicion of Plato’s motives does seem warranted because of the way Plato uses the form of the good to justify dictatorship.

What are Aristotle’s Four Causes and how do they relate to his empiricist method?

-Aristotle’s empiricism claims we can gain knowledge from experience.

-He thinks that universals like form are not abstract entities, but are aspects of the things we observe, a view called immanent realism. Material objects are thus hylomorphic, a combination of matter and form.

-He argues that to have knowledge of a thing requires understanding why it exists.

-We can determine the causal processes operative in the various aspects of a thing’s being which are responsible for the change we experience. This allows us to understand what we are observing and why it exists. We can thus gain knowledge despite the world being in flux, is Aristotle’s response to Heraclitus.

-Aristotle thinks there are four types of causation involved in change:

-Material= What something’s made of – e.g. the ‘wood’ of a chair.

-Formal= A thing’s essence or defining characteristic – e.g. the shape of a chair – a chair essentially has the shape of a thing that can be sat on.

-Efficient= What brought it into being – e.g. a carpenter.

-Final= End goal of the thing built into its nature – telos – e.g. for a chair, to be sat on.

-This is an early version of the scientific method. A scientist could explain that if you add the efficient cause of fire to a chair, then because of its material structure of wood the result will be ashes.

-This is how science works – we look for patterns in the world and try to gain general knowledge from them.

Why do modern scientists reject Aristotle’s idea of telos or final causation?

-At the beginning of the enlightenment period, scientist Francis Bacon claimed that the concept of ‘telos’ was unscientific.

-The modern scientific view is that the universe is just composed of atoms and energy in fields of force. There is no space in our scientific understanding of the universe for anything like purpose or telos to exist.

-Physicist Sean Carroll concludes purpose is not built into the ‘architecture’ of the universe.

-Telos looks like an outdated unscientific concept which people mentally project onto reality but doesn’t actually exist.

Is the modern science critique of Aristotle successful?

-The modern science critique of Aristotle is successful because it is an improved version of his own empiricist epistemology.

-Aristotle thinks an acorn growing into an oak tree must be explained by final causation, but modern science can explain it purely through material and efficient causation of the acorn’s DNA and environment.

-The change Aristotle thought telos was required to explain can actually be explained by non-teleological causation.

-So, final causation is an unnecessary unscientific concept.

-Modern science does show some details of Aristotle’s theory are not all correct, though material and efficient causation are still valid.

-Modern science isn’t attacking Aristotle’s method though, in fact it uses his empirical method but an updated version.

-So Aristotle’s general approach was right, even if it was underdeveloped and got some details wrong as a result.

What is Aristotle’s idea of the Prime Mover and why does he think it's necessary?

-To explain the ultimate source of the change we observe, Aristotle argued there must exist a prime mover.

-For Aristotle motion involves all the change we experience.

-Aristotle thought the universe had always existed, but thought that nonetheless the continual motion within it needed an explanation.

-Observation suggests this, e.g. if you roll a ball, it will stop. The stars and planets have not stopped moving, however. So, there must be a prime mover eternally sustaining the motion of the stars, as well as the terrestrial motion and change we experience.

-This ultimate source of motion could not derive its motion from something else. It must therefore be unmovable, with no potentiality to change, a being of pure actuality.

-It could not be physical, since material beings are subject to change and decay. It is an eternal immaterial mind. If it thought about anything changeable, it would itself change. So it must be engaged in pure contemplation, never thinking of anything else.

How does the Prime Mover cause motion and how is it different from efficient causation?

-Aristotle thought immaterial beings could not directly push or pull physical beings.

-So the prime mover is not the efficient cause of the universe or the motion in the universe.

-It is the final cause of the universe. It causes motion through the attraction of things to its perfection. Imperfect things oriented towards their good end are thereby attracted to the perfect actuality of the prime mover.

-This is what explains the motion that we observe – it is the transition of things from potential to actual through four causes due to attraction to the final cause of the prime mover.

How does modern science challenge Aristotle’s Prime Mover?

-Modern science since Newton has rejected Aristotle’s views on motion.

-Newton’s concept of inertia says that if you move something, it will continue to move unless met by an equal and opposite reaction. A rolling ball will stop because of the transfer of kinetic energy into friction energy, not because motion runs out.

-Inertia shows that continuous motion does not need a special explanation like a prime mover. Anthony Kenny concludes Newton’s law “wrecks” Aristotle’s argument.

-E.g. if you throw a ball in space – it will just keep going, because there’s no friction. So that’s why the stars and planets are still moving.

-So, according to modern science there is no need for the prime mover.

Is Aristotle’s method still valid?

-The concept of a prime mover seems outdated, though Aristotle’s attempt to find an explanation for motion was a valid empirical project.

-So, Aristotle had many outdated beliefs about the world, but his underlying method for knowing reality was valid. In fact that is the method Newton himself developed and used.

-Science is always progressing and updating, but Aristotle was right to use and pioneer the scientific method.