Compare Hume's Empiricism & Descartes Rationalism

University Degree Historical and Philosophical studies

Compare Hume’s Empiricism & Descartes Rationalism

What is a Rationalist and what is an Empiricist? We can answer this question on a number of levels, some of which highlight just how much these two traditions have in common, some of which emphasise their opposition.

The Rationalist believes that some or all of what is true knowledge is literally inborn with us; the Empiricist believes the opposite: all of our knowledge arises from our perceptual experiences in the world after we are born. The name Rationalism obviously derives from the word 'rational' which itself goes back to the Latin, 'ratio' meaning 'calculation'. This in turn goes back to another Latin word, 'ratus', which is the past participle of 'reor', meaning "think', 'deem', 'judge'. What runs through all of these is the emphasis on mind, an emphasis connected with the word 'rational' as well: rationalise, rationality, and so on. 'Empiricism' derives from another English word, 'empiric', meaning, 'derived from experience' (this itself going back to Latin and Greek words for experience). So in the plainest language possible, the Rationalist places the origin of our knowledge of reality in the powers of the mind, whereas the Empiricist places it in our powers of perception.

The most famous rationalist is certainly Descartes, who said that the true source of knowledge was the mind and reason. From his famous discussion of the piece of wax, Descartes established that knowledge is a priori (prior to experience), since, in the example, our senses perceive different objects even though we know that the wax is the same wax in either its solid or liquid state. .As the father of rationalism, Descartes, will say in the Meditations on First Philosophy: "Among my ideas, some appear to be innate, some to be adventitious ['coming from outside'], and others to have been invented by me." Descartes would also have to say that an innate idea is by no means always a conscious idea; otherwise, he would have to explain why, for example, children are not born with an immediate knowledge of God (one of Descartes' innate ideas) . So he says: "When we say that an idea is innate in us, we do not mean that it is always there before us - which would mean that no idea was innate." (In fact, Descartes here makes allowance for more than the objection concerning children's knowledge, but also for unconscious knowledge and the sleepers' knowledge).

On the other hand, David Hume, a famous empiricist said that experience (knowledge) is comprised of impressions and all of our ideas are derived from them. According to Hume, little human knowledge can be got from the . And he argued that we cannot justify our natural beliefs in the reality of the or the of an . From all of this, he concluded that a severe is the only sound view of the world.

When Descartes says that only some of our ideas are innate, it is also true that he thinks that innate knowledge is the only type ...

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When Descartes says that only some of our ideas are innate, it is also true that he thinks that innate knowledge is the only type of knowledge worth bothering with and that knowledge coming through the senses or invented by the mind (as opposed to being inborn with the mind) is hardly worthy of the name knowledge at all. It is an odd definition of experience that, at one and the same time, can admit that operations of the mind cannot be reduced down to sense experience and that there are no innate ideas or innate 'principles' in the mind.

To say that everything stems from experience says very little unless you give a special definition for experience. That is why the empiricist's ideas are often best seen as negative, defined more by what it denies than what it itself supports. What it denies, then, is most often what the rationalist advocates: the existence of innate ideas.

This issue of innatism is consequently the best way to characterise the division between empiricism and rationalism. But it is not the best way to characterise what each of these traditions thinks in its entirety. So we have to look at some more ideas belonging firstly to the Rationalists, whose four fundamental beliefs are:

1 True knowledge of reality is possible

2 This knowledge of reality is possible through reason alone

3 True knowledge forms a single system, a mathematical model being the ost likely candidate. 4. True knowledge is deductive.

The true sceptic must be sceptical even about his or her own scepticism which is no more than to say that they should be at least open to the possibility of real knowledge.

David Hume criticises the "dogmatic" or "excessive" scepticism in favour of a "mitigated" scepticism in Section Twelve of his Enquiry Concerning Human Understanding.

It is also this systematic scepticism that Descartes both attacks and exploits in order to save the possibility of real knowledge. Descartes brings in 'systematic doubt' to such an extreme that nothing is left that cannot have its existence brought into question, not the reality of God, other peoples' minds, the physical world (including my own body), nor even the truths of mathematics such as 1 + 1 = 2'. But one item of knowledge this doubt leaves intact, is the very fact that there is a someone doubting all of this at all. The doubt itself cannot be doubted, which is the same as to say that one must doubt the universal extent of doubt, or be sceptical about our scepticism.

Both a rationalist and an empiricist, Descartes and Hume, end up on the same side, justifying the scope of any extreme scepticism. Where a difference remains between these two thinkers, is that Descartes thought from the viewpoint of a sceptic in order to argue in the end for a fixed position, whereas Hume was always a sceptic and his place in philosophy is one of consistent doubt and criticism. Descartes argues against scepticism and for knowledge. Hume, on the other hand, argues both for and against scepticism in opposition to the claims of reason.

Because our perceptions can be faulty, fooled by illusion or in dreams, for example, the Empiricist would say that knowledge of the world can never be certain. Descartes, on the other hand, would say that the world can be known without a doubt through reason: we can reason about our perceptions to the point where we realise that they must, in general, be accurate. (The type of reasoning Descartes has in mind, is that a non-deceiving God (and God cannot be a deceiver) could not allow anyone who is carefully examining his or her perceptions to be systematically fooled about what the world is really like.)

The Empiricists will say that true knowledge can only relate to rationality, that is, the ideas of the mathematical sciences. Descartes only differs in allowing reason to extend its natural light beyond mathematics to what we perceive.

‘True knowledge forms a single system'. Descartes, as a Rationalist had a vision of a project that would bring together all the branches of knowledge under this one model. Contradiction is impossible. This is the certainty the Rationalists want. The Empiricists, seeing the rest of our knowledge as less certain, take another model of argument as the blueprint for how we learn things about reality. This model is called an inductive argument. This is a method of reasoning by which a general law or principle about something is inferred from observing particular cases of this something. If we look at Hume's favourite example: our belief that the sun will rise tomorrow. Clearly, this is a matter of fact which rests on our belief that each sunrise is an effect caused by the rotation of the earth. But our belief in that causal relation is based on past observations, and our confidence that it will continue tomorrow cannot be justified by reference to the past. So we have no rational basis for believing that the sun will rise tomorrow. Yet we do believe it!

Descartes said that, most of human behaviour, like that of animals can be explained amd cleverly designed machines could successfully copy nearly all of what we do. He argued that it is only the general ability to adapt to widely varying circumstances—and, in particular, the capacity to respond creatively in the use of language—that provides a sure test for the presence of an immaterial soul associated with the normal human body. He also said that no matter how human-like an animal or machine could be made to appear , it would always be possible to distinguish it from a real human being. Although an animal or machine could perform any one activity as well as (or even better than) we can, he argued, each human being is capable of a greater variety of different activities than could be performed by anything withour a soul and although an animal or machine could possibly make sounds resembling human speech in response to specific stimuli, only an immaterial thinking substance could engage in the creative use of language required for responding appropriately to any unexpected circumstances. My puppy is a loyal companion, and my computer is a powerful instrument, but neither of them can engage in a decent conversation.

The Rationalists and the Empiricists were both concerned with questions of methodology, and thought it was vital that both the established mathematical and emerging physical sciences should rub off onto philosophy. It was as much the certainty of mathematics that appealed to the Rationalists as it was the practical benefits produced by the physical sciences that appealed to the Empiricists. Each wanted philosophy to have the status of being a science, with man standing for human psychology: his knowledge, passions, and morals, as well as what distinguishes him from other animals, 'the beasts'.

Eighty per cent of Descartes writing was what we would today call science, yet he is often stereotyped as the armchair philosopher producing descriptions of the world a priori. Hume, on the other hand, the great sceptic about reason, was almost hyper-rationalistic in stretching the consequences of his arguments to their most unintuitive, impractical, and extraordinary limits and the proper goal of philosophy is simply to explain why we believe what we do.