Welcome to rationalism
Rationalism, like most of western philosophy, is rooted in Ancient Greece dating back to Plato and Zeno. However, it lay pretty dormant until the 17th and 18th centuries, when it was bought back to the forefront by Descartes, amongst others. Rationalists, sometimes called the ‘armchair philosophers’, seem to have given philosophy a bit of a bad rep in modern society. People are much more concerned with science (empiricism) nowadays and the idea of thinking through problems rather than inductively working them out through experimentation seems a little alien to the plebs. Not us, however.
What is rationalism?
The answer’s in the question. Rationalism is from the Latin word ratio meaning reason. So, Rationalists believe that reason is the primary source of knowledge, providing justification for beliefs.
Exempli Gratia
Let’s say you’ve got a fifty pence piece in your hand. You toss it up into
the air. That coin will come back down, but how do we know? Rationalists
hold that we have knowledge of certain a priori principles, like the laws
of physics (and by extension: gravity), that are the basis for the world.
Michael Lacewing and Jean-Marc Pascal
'Armchair philosophers'
The term isn’t actually accurate since all Rationalists, bar Plato, acknowledge that everyone needs a bit of sense experience sometimes.
- We need to be equipped with training in language and logic (i.e. maths) to be able to rely solely on reason.
- Particular facts can only really be induced (a posteriori). Take, for example, the distance from an examination hall you once sat in to the examiner’s house where your paper was marked.
However, the rationalist maintains that basic facts of reality can be deduced using our reason alone.
How does it work?
Rationalists argue that either...
...and that's how we get knowledge!
What's so special about knowledge via reason?
Rationalists advocate knowledge through reason over knowledge through experience because:
- Innate knowledge is superior.
If you look at the world around us, everything is in a state of flux. Things are dying, things are being born: there’s change. If we’re to rely on our senses, we’re relying upon this changing world. If we’re to rely on our reason, we’re immune from change since the laws of maths or physics simply aren’t subject to change. - Some knowledge is restricted to reason.
According to some rationalists, some knowledge is only accessible by reason. Think of maths.
Enter: Zeno 
I’m sure you’ve heard nothing about him, like most Greek philosophers he stands in the shadows of Plato (ha, slight pun: shadows, Plato, imago formi etc.) and Aristotle: the big guys. But, that’s not to say he didn’t do some good work in his time. Consider the following:
“In a race, the quickest runner can never overtake the slowest, since the pursuer must first reach the point whence the pursued started, so that the slower must always hold a lead.” 2
- A tortoise and Achilles, a Greek hero, are having a race.
- Achilles, being nice and all, gives the tortoise a head start. The tortoise plods along at a slow, but constant speed.
- Achilles first has to get to where the tortoise originally started, and by that time, the tortoise has moved on.
- So now Achilles gets to where the tortoise has moved on to, but the tortoise has moved on again.
- So Achilles runs to where the tortoise has moved onto again, but the tortoise has, of course, moved on from there, too.
- And so on...
Confused? Don’t be. You might be thinking “but people do overtake others in races” and you’d be right. That’s not the point, the point is that we’ve learnt that time and space cannot be divided into infinitely small parts… it just can’t happen.
And, we did it all using reason. We didn’t go out, collect Achilles and a tortoise and pit them against each other in a race… we didn’t even leave our armchair!
Fun with empirical and logical truths
They don't sound all that interesting, but believe you me... they are!
| Empirical truths |
Concerns truths that could have been otherwise. The
flag of the EU is made up of 12 stars in a circle, but these
stars could have easily been arranged in a square. They are contingent,
meaning they rely upon something else and that they can, and do,
change. A sort of pre-historic duck that was thought to be extinct,
for instance, turns out to be thriving in a remote part of the Congo. Contrariwise, something that’s empirically false may, in the future, become truth. Empirical truths are less certain. |
| Logical truths | Now these babies… they’re necessary.
There is no possible way that a logical truth could ever be (or
have been) otherwise. Up is not down is a logical truth. On the
flip-side to that, Up is down is a logical falsity. Logical truths are an absolute certainty. |
Comprenez? Oui? Super, let’s move on to Plato...
Plato
Plato was a major rationalist. He rejected all sense experience. For him, the problem of the one and the many meant that empiricism was useless.
“No man ever steps in the same river twice, for it's not the same river and he's not the same man.” 5
Yep, that is the problem of the one and the many by Heraclitus, quoted by Plato in Cratylus. As mentioned previously, the world is in a state of flux, so knowledge from a state of flux leads to knowledge that is itself flawed.
Instead, Plato deduced that we ‘recollected’ knowledge from ex-temporal (outside of time) abstract entities called forms. Each object or concept in this world has a correlating form in the, aptly named, realm of the forms. The forms are immune to the constrains of this world, like decay, so they are perfect in every way.
The following is from Bertrand Russell
There are many individual animals of whom we can truly say ‘this is a cat’. What do we mean by the word cat? Obviously something different from each particular cat. An animal is a cat, it would seem, because it participates in a general nature common to all cats. Language cannot get on without general words such as ‘cat’, and such words are evidently not meaningless. But if the word ‘cat’ means anything, it means something which is not this or that cat, but some kind of universal cattiness. This is not born when a particular cat is born, and does not die when it does, in fact, it has no position in space or time; it is ‘eternal’. 6
Plato has his own section here at Pisp.co.uk, visit to learn more.
Clear and distinct ideas
Descartes
Let's try and clear things up (pun)...
- An idea is clear if I say so we cannot help but take notice of it. So, strong physical sensations, like pain, or thoughts like the desire for something.
- An idea is distinct if it cannot possibly be confused with anything else. Think about a time you've had a headache. The pain is clear, but it's indistinct since you don't know exactly where the pain is or what's causing it.
Final thoughts
Well, you’ve made it this far, well done!
We’ve not discussed the problems or criticisms of Rationalism here, because the next article is Rationalism’s biggest criticism: Empiricism. Tune in next time to find out more.
Remember… always think outside of the Poke Ball!
Test yourself
- Rationalism quiz in the Interact section.
Footnotes
- Lacewing, Michael and Jean-Marc Pascal. Revise Philosophy for AS Level. Canada: Routledge, 2007.
- Aristotle. Physics. United States: Oxford University Press, 1996. VI:9, 239b15.
- Zeno's Paradox - Image from Wikipedia (en). Used on Pisp.co.uk as it is public domain under EU and US law.
- Extract from School of Athens (1509) Raphael - Image from Wikipedia (en). Used on Pisp.co.uk as it is public domain under EU and US law.
- Heraclitus. Plato. Cratylus. USA: Hackett Publishing Company, 1998. Fragment 41.
- Russell, Bertrand. History of Western Philosophy. London: Routledge, 2004.
