The 17th Century Rationalists and how their influence can be seen today

This essay sets out to discuss a number of views of the relationship between mind and body. Can our minds and our physical brain be two separate entities that behave totally independent of each other? Are they separate but perhaps inter-related and running parallel to each other with our inner and personal mental events being elicited by events in the brain?

Or is the mind no more than a side effect of our physical brain process meaning that qualia or our sense-data and emotions don’t really exist and that these processes that lead to our behaviours are simply physical ones that are intrinsically part of us as human beings being derived from the universe as a whole? I will discuss the views and ideas of the Rationalist philosophers Descartes, Spinoza and Leibniz and the extent to which their ideal help to illuminate contemporary discussion such as the Turing Test and the Matrix.

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Rationalists believe that knowledge is gained by using a priori reasoning as opopsed to a posteriori reasoning, a distinction among judgements, propostions, concepts, ideas, arguments or kinds of knowledge. A posteriori presupposes sensory experience while a priori is independent of it. An a posteriori propostion argument relies on specific information which is derived from our sense perceptions while an a priori proposition is determined by reasoning alone. For example 1 + 1 = 2 is known as an a priori deduction while a statement such as the Menai Bridge links Caernarfon and Anglesey is posteriori propostion.

I will also discuss Descartes’ question of our existence and how important it still is to philosophers and scientists who study Artificial and Computer Intelligence, looking, for instance, at the Turing Test as an example of the way in which his ideas have relevance to the foundations of academic debates about AI. I will also discuss the recent trilogy of films the Matrix, which is an example of the way in which his ideas are relevant to discussion of AI in popular culture. What is the relationship between events in the brain and our private, inner, subjective experiences of our inner mental being?

Not assuming that consciousness and mind are one and the same, consciousness could simply be a facet of the mind, but the issue here is whether consciousness exists. Before the 17th Century’s Scientific Revolution, little was known about how our brains worked and the distinction between mental and physical phenomenon was vague, but it was understood that there was a difference between our private thoughts and experiences and the more public outside world in which we all live our day-to-day lives.

Perception was not understood at this time, making boundaries between our inner selves and the world rather fuzzy and unclear. It was believed that noise, colours, and sights, the making of our phenomenal world, are objective phenomenon belonging to the public world. Descartes’ program in the Meditations was to place the structure of our knowledge onto a secure foundation. He set out to review his beliefs, many being contrary, some more or less justified than others. He even argued that, while propositions of mathematics, seem certain, they sometimes turned out to be false.

He decided to put his jumble of beliefs in order. He needed to begin with the most certain and fail-safe, but how did he decide on a starting point. He noted that many of his beliefs derived from his senses and perception and that senses could be misleading. For example a stick looks bent when partly submerged in water when in fact it remains the same. The size of the sun and the moon can be perceived to be much smaller than they are in actual fact. We can also hallucinate and believe that something exists when in fact it doesn’t.

He decided never to trust anything that had deceived him once and thus decided to reject sensual information as being infallible. We may think that our senses are deceiving on occasions, Descartes could have been sure that he was in his study, that he was a Frenchman who was interested in philosophy etc. But he recognised that there was no clear and definite way of differentiating between a world of dreams and reality. The same applies to us. How can we be absolutely sure that the life we live is not part of a dream? There is no failsafe way that we can distinguish between dreaming and being awake.

Dreams can often be so vivid that we are convinced they happen. We sometimes recall events and remain convinced that we did experience them but later “realise” that we must have been dreaming when doubts are raised or we find proof that these events never actually occurred. Decsartes believed the human mind that was created by God was able to be certain of material things when conceiving them mathematically. God, according to Descartes had the power to create whatever we perceived and he though God too good and kind to allow the human mind to mistake what it conceived matter mathematically.

But even though the method of mathematics is sound it is always possible to make mistakes in our calculations. He therefore concluded that there was no real way to know anything. However this was not his intention – he wanted to find certainty. Descartes decided that instead of examining each belief individually, he would examine each against a method of doubt. The idea was to question the source of each of his beliefs and to ask whether the source was infallible. If he failed to prove its infallibility, he was then sure of the unreliability of that source for a foundation of knowledge.

Descartes claimed that his method imitated that of the architect. When an architect wants to build a house which is stable on a piece of ground where the topsoil is sandy but over rock, he removes the sand and anything else that may be mixed up with the sand by digging trenches. He similarly began by removing all doubt and throwing it away like the architect did with the sand to ensure that the foundations are stable. This is called foundationalism where every doubt is cast aside to return to a safe and sure foundation. The method he used is called the method of doubt.

Some wonder how we can wonder we are not dreaming. Some agree that you cannot feel pain in a dream, but others say they have. The argument that dreams are not related to memory is strong because most people do not remember their dreams. Descartes explains that in a dream you can feel as if you are using all your senses, but they seem to become more vague than when awake. Descartes struggles with the dream issue until he comes upon his conclusion. So Descartes rejected all perceptual knowledge and turned to what he believed on account of his own internal reflections.

But surely he knew that 2 + 3 = 5, that a mother is older than her daughter, a triangle has three sides? But Descartes said that he could have been the subject of a huge deception. Then he imagined another scenario whereby he might have been deceived by a malignant and powerful being into believing anything that he so chose by being capable of manipulating his thoughts, as God could if he weren’t supremely good. However, Descartes realised that there is one proposition that neither the evil demon nor even God, could ever make false. This is that at any time when he thinks he must exist in order to be deceived or otherwise.

By such reasoning Descartes is led to the cogito as the one certain infallible rock of knowledge. For Descartes, the cogito was the beginning of a project in which he proved the existence of God to guarantee the rest of human knowledge. In his Second Meditation, Descartes decides that, even if he doubts everything, including the existence of his body, the only thing he cannot doubt is that he is doubting. This leads to the famous Cogito Ergo Sum, or if you’ve somehow managed to ignore anything that anyone has ever said to you about Descartes, “I think; therefore, I am”. I am only a thinking thing, that is a mind”. This, to Descartes is the first and primary clear and distinct perception. He uses wax to illustrate and prove that, although he does have clear and distinct perceptions about things, these perceptions can only come from reason, not sensory perception. He decides that whatever he can perceive clearly and distinctly – taking his cue from the Cogito – must be true. These clear and distinct ideas offer Descartes a glimmer of hope as far as reconstructing truth and the sciences.

But he still has a problem – in his Third Meditation he thinks that a deceiver may be giving him false clear and distinct perceptions. It therefore became paramount that Descartes found proof of the existence of God as a perfect being. He begins to sort through his consciousness to see if he has any clear and distinct perceptions that could not have come from himself. He goes on to suggest a three-fold distinction to reality: formal reality (a vase), objective reality (the vase which exists in your idea of a vase) and material reality (the thought which allows you to compose the idea of the vase).

But these terms don’t seem to match up with their definitions, nevertheless he puts these blocks together and builds the Principle of Causality which says that any idea you have comes from a cause which has at least as much formal reality as there is objective reality contained in the idea. If you have an idea of something, whatever caused that idea has to be greater (be “realer”) than whatever you are conceiving of. Now Descartes thinks that he’s great enough to have come up with most of his ideas, but his idea of God is of a being so perfect that he could not have come up with it himself (i. he’s not as great as the being he conceives). Therefore due to the Principle of Causality, God must exist because He must at least be as real as Descartes’ conception of Him. Now, since God exists, Descartes can depend on his clear and distinct ideas, since a perfectly good God would not deceive him or permit him to operate under a totally false conception of the world. The fact that the proof of God’s existence depends on Descartes having a clear and distinct idea of Him, but the validity of Descartes’ clear and distinct ideas depends on God’s existence is known as the Cartesian Circle.

The Cartesian Circle is basically the relationship between his belief that “God exists” and his epistemological principle the “Whatever I clearly and distinctly perceive is true”. It can only be the existence of God that can guarantee this principle to be true, since He is no deceiver. Descartes believed in the existence of God because he clearly and distinctly perceived that He existed. No argument to show that God exists can be certain unless one is certain of one’s own reasoning, but according to Descartes one can’t be certain of one’s reasoning unless one is certain that God exists.

His critics unimpressed by his weak version of Anselm’s ontological argument or his own “trademark argument” to prove the existence of God, have taken the Meditations to be the definitive work of epistemological scepticism. Descartes distinguished between a material and a thought substance, both being totally independent of each other, but he found it difficult to explain how they interacted how our thoughts lead to movement of limbs and how we feel pain and tiredness, the effects of alcohol on our bodies and psychosomatic diseases.

He suggested that the pituitary was the link between these two substances of thought and nervous system thus leaving the philosophical problem still a mystery. Descartes did not explain fully how the mind and body interact. As is well known, Descartes chose the pineal gland because it appeared to him at the time to be the only organ in the brain that was not bilaterally duplicated and because he believed, erroneously, that it was uniquely human. Classic Cartesian dualism invokes God at the point of interaction and for Descartes, the physical point of interaction where the miracle occurs countless times each day was the pineal gland.

Descartes like other modern interactionists take it as given that interaction between physical and mental events occurs thought they can in no sense explain it in causal terms – later writers such as Leibniz and Spinoza challenged Descartes’ ideas. Spinoza, like Descartes, was concerned to set knowledge on a logical foundation and despite being a work of ethics, his ethical conclusions must first be founded on a number of ontological, metaphysical and epistemic beliefs. Each of these is, in turn, demonstrated by geometry. Spinoza, unlike Descartes, believed that everything in the universe is one.

There is only one substance and that substance we can conceive of as either Nature or God. This substance has infinitely many attributes but human beings being finite, can only perceive two of them, extension and thought. Unlike Descartes, who thought mind and body were two separate entities, Spinoza argues that mind and body are just different ways of conceiving the same reality. This reality, Nature or God, is wholly self-contained, self-causing and self-sufficient. Everything in the Universe is part of God and everything that happens is a necessary part of expression of the divine nature.

This view means that there is no free will from the realm of human actions. After all, if human beings are part of the divine reality there is no room for independent causal actions. Spinoza is more than happy with this conclusion, he is a determinist he believes that experience proves that men believe themselves to be free as they are conscious of any actions but are not aware of why such actions are determined; he also claimed the mind’s dictates to be a different name for varying appetites of varying body states. He does however make room for some freedom, though not the kind other philosophers are familiar with.

Spinoza said that each individual is a localised concentration of the attributes of reality, really a quasi-individual, since the only true individual is the universe in totality. Insofar as the quasi-individual is ruled by his emotions, he isn’t free and at the mercy of finite understanding. To become free, he must by means of rational reflection understand the extended causal chain that links everything as one. To become aware of the totality of the universe is to be freed from, not causal determinism, but an ignorance of one’s true nature. How do we therefore explain sin and evil?

Since everything is part of one reality there is no such thing as evil from the viewpoint of the whole – “sub specie aeternitis” (from the aspect of eternity). That which appears to be evil does so because we lack the understanding to see the bigger picture, the chain of causes that make all events a necessary part of divine reality. Though this shocked many in Spinoza’s day, it reflects the same sentiment as those Christians who preserve in the face of adversity by claiming that “God moves in mysterious ways” and “ours is not to reason why”. Of course, for Spinoza, the reason why is exactly what we must do to attain freedom.

The argument against Spinoza’s theory is his belief that human emotion or our senses are unreliable, if we believe his theory how can we in fact experience emotions such as love and sadness. Known as the third of the great rationalists Leibniz’s philosophy, like Descartes and Spinoza stems from the Aristotelian notion of substance bearing property but not being a property in itself. Although rejecting Spinoza’s view that there is only one substance Leibniz believed in infinity of substances and called them “monads”. Monads can be compared to Democritus’s atoms.

Like atoms monads are the ultimate indivisible elements of reality of which all material things are constituted but not themselves extended nor composed of matter. In a completely original thesis Leibniz holds that a monad is a psychological entity, indeed at times, when embodied in human beings, he called them “souls”. Fundamental to Leibniz’s “monadology” is the notion that a monad is a unified, independent substance and accordingly, everything that is true of a monad is contained within it and it therefore cannot enter into any causal relations with other monads.

Leibniz expressed this point in a logical way, he had the extreme view that every truth is a necessary one and he believed that everything happens the way it does because God has chosen for it to be that way to make the best of every possible world. It could only be different had he chosen to actualise a different possible world. This makes personal identity therefore a very rigid phenomenon. I would not be writing this essay at this computer at this moment of time, the Americans would not have caught Saddam Hussein this weekend.

To deny these true propositions would mean taking away something essential from individuals and making them what they are not and naturally following Leibintz monad concept. There are many critics to this theory though as it eradicates any possibility of freewill, a notion strongly defended by Descartes. But, on the other hand, if this theory had an element of truth and that our lives are already mapped for us there could be a possibility that some people’s claims of being able to predict the future and experiencing visions and dreams that come true actually do happen.

This could simply be our imagination, a weak link in the system or if there is a God he may be allowing us some insight, albeit haphazardly, of our fate without affording us too much knowledge and maintaining a mystique. Leibniz believed in a “pre-established harmony” – there is no interaction between the mind and the brain, the mental and physical correspond like two clocks that keep perfect time even thought they aren’t connected. This theory’s weakness though is that it is not clear that mental events, unlike brain events, follow a continuous, self-contained sequence.

Consciousness is sporadic. There is so much associated with our mental life happening below our consciousness threshold. I mentioned earlier the movie “The Matrix” in which the main character Neo is caught between what he thought to be reality and a whole new world controlling everything he thought to be real. If I were Neo, I would not truly be able to know that I was in the matrix, but it is rational to believe that I am in the matrix and that I will enter back into reality later.

The proof that I can know that I am in the matrix and that I will return to reality comes from the responses of foundationalism, the essence of what we are certain of like Descartes’ cogito theory. The Matrix depicts a breed of AI computers taking over the world by harvesting human embryos in laboratories called “fields”. They’re kept “alive” by being fed through tubes in which they are immersed in a jelly like fluid in cocoons. The energy to sustain them comes from the electricity produced by the billions of humans being preserved like this.

This is a sophisticated computer program “The Matrix” creating a “world” inhabited by the consciousness of the human batteries. They can see themselves walking, talking, and working. The matrix has created this tangible illusion. But a group of human miscreants learn its secrets and live underground aboard a ship while communicating with a halcyon city called “Zion”. Cypher, one of the rebels poses the main dilemma of the movie by asking whether it is better to be happy in a perfect illusion or to be unhappy but free of its hold? The Matrix controls the minds of all the humans in the world.

It is a bridge between them; they inter-connected through it, making them share the same sights, smells and textures. The Matrix is sufficiently complex to allow for this apparent lack of determinism and freewill. The root question is: is there any difference between making decisions and feeling certain of making (not having made them)? Philosophy is based on questioning and searching for truths. In Matrix, the search and questions were for the truth about our own existence, just like Descartes, Spinoza, Leibinz did in the 17th Century.

We see that were are here on earth, we feel and know things but why? Is it because we are told to believe these things? Neo is our guide throughout the movie, we venture into his thoughts and doubts the same as we have ourselves. We may have thought that our life is merely a dream and that we will wake up one day and not be able to remember anything. “For I now notice that there is a vast difference between the two, in that dreams are never linked by memory while all the other actions of life as waking experiences are.

If, while I am awake, anyone were suddenly to appear to me and then disappear immediately, as happens in sleep, so that I could not see where he had come from or where he had gone to, it would not be unreasonable for me to judge that he was a ghost, or a vision created in my brain, rather than a real man. But when I distinctly see where things come from and where and when they come to me, and when I can connect my perceptions of them with the whole of the rest of my life without a break, then I am quite certain that when I encounter these things I am not asleep but awake.

And I ought not to have even the slightest doubt of their reality, if after calling upon all the senses as well as my memory and my intellect in order to check them, I receive no conflicting reports from any of these sources”. (Meditation 6, para 89-90) This movie is an image of the minds and thoughts of anyone who has ever had these thoughts and intrigues. We can perceive the Matrix to be whatever we want it to be. It is a blank canvas to program will. The mind is portrayed as a white room with no walls or furniture just space. Ideas, emotions and senses that we consider real are introduced by the Matrix but how do we know what is real?

Our experiences teach us to believe in reality. I see a red rose but to you it may be pink. Philosophy is integral to this movie the character names have been carefully chosen, Thomas Anderson the computer hacker is the chosen one. Morpheus is responsible for choosing him. He is referred to as the biblical “doubting Thomas” before his name is changed to Neo, meaning new or change, and a symbol of the need to discover the truth. As soon as he becomes a believer he became Christ like in having to face the decision of sacrificing himself to free the rest. This could be likened to Christ dying on the cross.

Morpheus could be John the Baptist searching for Messiah or the chosen one in the Matrix relying on faith to guide him. Trinity could be a symbol of the Holy Spirit one person but a combination of the three strengths. Neo, who may be symbolic of Christ could as easily be symbolic of Descartes – “I think therefore I am” questioning everything. The use of machines to program humans is in line with Descartes viewing all motions as mechanical, but not being able to control the soul which is contrary to Spinoza’s reasoning; although mechanical he did not believe in a separate emotional state or soul.

Founder of computer science Alan Turing posed the question “Can Machines think? ” in his famous paper Computing Machinery and Intelligence. The answer of course depends of exactly what is meant by “machine” and “think”. He defined a game with three players. Player A is to act as an interrogator, and the object of the game for the interrogator is to guess the sex of the other two players, one of which is a man, and the other a woman. All the players are in separate rooms and send and receive questions and answers via teletype terminals.

For Player B the object of the game is to confuse the interrogator and hide the identity of his/her gender. For Player C the object of the game is to help the interrogator to guess his or her gender correctly. Clearly, since the interrogator does not know which player is trying to help him and which is trying to deceive him he must be careful in the way he questions. Now Turing asks, what will happen if a machine takes the place of Player B in this game? Will the interrogator guess more or less correctly than he would when the players are both people?

The answer to this question, Turing tells us, will settle the question of whether a machine can think. Why? Because any machine sophisticated enough to replace a person in the game without the detection of the interrogator (or at least with a detection rate no worse than a person) must possess just the same intelligence as a person. The assumption, in other words, is that anything that responds intelligently is, by that very fact, intelligent. Turing’s ‘imitation game’ raises a number of interesting issues for psychologists.

In particular, is it true that imitation is really enough to satisfy us that a machine can think? A child can imitate the behaviour of an adult, but is not thereby and adult, and neither is player B, if he is a man and successfully fools the interrogator that he is a woman, thereby a woman. So why should we suppose that a computer that imitates the behaviour of a thinking person, is really thinking? The issue is complex and turns in part on the assumption that the level of sophistication required to fool the interrogator might only be achieved by something that was indeed a thinking being.

On the other hand, and this is probably closer to Turing,s own view, since the only criterion we have of conscious thought is how it is manifested in behaviour (including verbal behaviour), it can make no sense to call one thing “thinking” and another “non thinking” if their behaviour is indistinguishable to a competent judge. Of course, the imitation game does not imply that any machine could ever pass the test, but does give us, if one agrees with Turing, a test that any candidate machine should have to take. Turing professed that by the end of the twentieth century we would have machines capable of passing the test over 70% of the time.

His optimism has yet to be borne out but does remain a fantasy to many such as the makers of movies like the Matrix. While Descartes would reject the Turing tests as it does not take seriously the notion of consciousness Spinoza might accept it as stated by Delahunty 1985, pg 210 that Spinoza believed that “The human body in particuarly is, like any organic body, formed without a conscious purpose; like any other body, it is determined by efficient auses alone, and operates in accordance with purely physical laws.

If we like, we can say that it is mechanically explicable, but we ought not to say that it is a machine, if machines require designers” Many questions remain unanswered and we are no nearer to solving the mystery of the mind in the 21st Century as Descartes and his contemporaries were in the 17th Century. Computers have come a long way since the Turing Machine was first invented and are capable of deceiving us by virtual reality tricks as demonstrated in Science Fiction films such as the Matrix which suggest the notion of a God and a perfect being like Descartes’ and Leibinz’ quest for proof of God’s existence.

The white room portrayed in the Matrix can be likened to Descartes’ foundationalism theory, the image of a blank canvas as a starting point on which to place our ideas on can be compared to Descartes’ architect theory to remove all knowledge and ideas and start looking for answers with a clean slate. Our bodies can also deceive our minds eg. amputees sometimes feel pain or sensations in limbs that have been removed and this can go on for years after the amputation.

This can be compared to Descartes’ use of a wax candle to explain illusions and the stick in water but a stick in water would not deceive a blind person as he would use his sense of touch to “see” the stick. We can “fly” planes in flight simulators or experience hurricanes without even moving from our seats. Descartes believed that God the perfect being created us and that he is not deceitful and therefore we must exist.

But he believed the body and mind to be independent and even when our bodies perish our minds or souls will remain. This gives us the impression of millions of souls travelling around the universe that attach themselves to material bodies every so often but for what purpose we ask? We are actively searching for proof of life on other planets and have been sending space crafts to other planets in an attempt to bring back proof of life or whether there are signs that life could have once existed there at any time in the past.