Well, That Just Smacks of Dualism!

     A long time ago I  read a humour piece in a local newspaper (this was pre-internet).  The article was entitled something like,  "Random Interjections to Throw Into Any Conversations That Will Make You Sound Smart".  Anyway, as you might gather from the title, the author, with humour intent, had come up with a list of lines you could say to make yourself sound smart.  "Well, that just smacks of dualism!" was one of them.  Ok, somehow explaining things takes all the humour out of them...lets get back to philosophy...

Dualism

     Ok, so what is Dualism? Simply put it is the philosophy that all disagreements should be resolved by means of a dual.  I kid! I kid!  I really should stop with all the jokes, I stand to lose all five of my readers.

     The truth is that the typical Joe on the street is a dualist.  Shoot, now I can't say that without wanting to make some terrible pun.  Ok, reset button.  A dualist is someone who believes that the mind and the body are distinct "substances" which somehow get united in humans.  Before I get into the implications of this view, I want to sketch out how Descartes argues for it.  And before I do that I will ever so briefly review the philosophical context in which Descartes came up with his view.

Philosophical Context

     The notion that mind and body are distinct entities is still quite common amongst the unwashed masses of today (guess if I'm a dualist or not!) but at the time Descartes wrote there was no such view at the time (Platonism had fallen out of fashion).  The prevailing view was the scholastic view, which arose out of Aristotelian thought.  Essentially the idea was that every class of thing was an individual substance.  For instance, an oak tree was one type of substance while a cat was an entirely different type of substance.  Substance for the scholastics is a thing's essence; and every class of thing has a unique essence.  

     Not so for Descartes.  In his view the form of matter is simply different expressions extension, such as shape and size.  Mind does not have the qualities of physical things (body) so therefore it is a separate substance.  For the scholastics Mind (aka "soul") was something that arose out of the form of matter.  The form that matter takes when it forms a human brings about a soul/mind (although, in the special case of humans, it required an act of god--usually two waves of his magic wand, three for some people).  For Descartes the mind doesn't require a body, but for the scholastics the mind does.

Arguments for the Existence of Material Things, and the Real Distinction Between Body and Mind

Overview

     Ok, enough about the Aristotelian view; out with the old and in with the new, I say!  Some of Descartes arguments rely--actually most--on previous sections where he "proves" the existence of a perfectly good, all powerful god, and that anything he perceives clearly and distinctly must be true (Doctrine of "Clear and Distinct").  The really strange thing is that for the existence of god he uses 2 crap arguments: "The Craftsman" argument and a modified version of the ontological argument which had been dismissed back in the 11th Century when St. Anselm first came up with it.  Even Descartes' contemporaries couldn't understand why he used it.  Anyway, basically it's a crap argument but if you're interested here's a good discussion of it it along with its objections. 
   http://plato.stanford.edu/entries/descartes-ontological/
This blog will not be party to crappy arguments!  Anyway, the validity of dualism doesn't depend of there being a god but for fun we'll temporarily suspend judgment and grant Descartes his assumptions. 

Arguments for the Existence of Material Things

Argument 1 The Imagination:   Descartes argues that (and I'm not sure I completely understand his argument) that we can derive the existence of the body from the fact that we have an imagination.  The first step in this argument is to differentiate between the imagination and "pure understanding".  To demonstrate/define these two qualities Descartes uses the following example:  When you imagine a triangle you not only understand the concept of "triange", i.e., that it is a figure with 3 connected lines whose 3 interior angles equal 180 degrees, but you also have in your "mind's eye" an image of a figure with 3 sides.   The same is true if we want to imagine a pentagon.  We have both an understanding of what that concept is comprised of and we have an image of it in our minds eye.  Now try to imagine a chiliagon--a thousand sided figure:  You understand that the concept of a chiliagon has 1000 sides and 1000 interior angles but try as you might you cannot accurately imagine a chiliagon  You might be able to imagine something resembling a chiliagon but there's no way that you could distinguish it in your mind from a 999 sided polygon.  

     The fact that we there are things that we can understand conceptually with our "pure understanding" that we can't imagine is evidence that these two abilities are distinct.   Also, Descartes asserts that the ability to understand something is necessary to the conception of "mind" (in the sense that he is a mind) but that the ability to imagine something is not necessary--it is a mode of Mind.  In other words, I can still be a thinking thing without being able to imagine, but I can't be a thinking thing without the ability to understand things.   We could contest that we may think we understand things when if fact we don't (kind of like how I feel about his whole argument).  I know from taking logic and math classes that many times I thought I understood a concept only to discover that I hadn't.  Did I cease to become a thinking thing?  Maybe.  Did I lose my Mind? Yes.  I'm not sure if this is a real or relevant problem for Descartes so we'll leave it at that. 

     "But so what?" you ask, "so what if "pure understanding" and the imagination aren't the same, and that one is necessary to Mind and the other isn't.  To be honest I'm asking the same thing but lets see where this goes...

     One reason this distinction is important, although it's not relevant to proving the existence of physical things, is that it is an argument for his metaphysics.  Recall that for Descartes there are only 2 basic substances in the universe: Extension (body) and Mind.  Some properties are intrinsic to a substance and some are not.  In the case of Mind, thought is necessary and intrinsic, but imagination is not; nevertheless it is a possible property/mode of Mind only--not Body.  An analogy with Body would be that all bodies have mass, but not all bodies have colour.   Mass is a necessary property and colour is not.

     Ok, back to how this imagination-understanding distinction can prove the existence of Descartes' body.  This is the part of the argument that I either don't understand or it just doesn't make sense.  I'll let you judge for yourself.  Here are the exact words (maybe you can explain what I don't understand):

"When the mind understands it in some way turns toward itself and inspects one of the ideas which are within it; but when it imagines, it turns toward the body and looks at something in the body which conforms to an idea understood by the mind or perceived by the senses.  I can, as I say, easily understand that this is how imagination comes about, if the body exists; since there is no other equally suitable way of explaining imagination that comes to mind."

      My interpretation is this:  in Descartes' metaphysics of Mind and Body, Mind can only have properties of thoughts, that is to say, it cannot have any properties that belong to Body (such as extension, size, mass, movement, shape).  The only way that it can have content about bodies, upon which to apply understanding, is if it is somehow connected to a body.  Essentially, Descartes' argument is that imagination is a product of the special union of Mind and Body that is a human.  Because in humans the substance of Mind is magically linked to Body, properties that belong only to Body can be smuggled into the content of our Minds (in the form of our imagination)...clearly there is "no other equally suitable way of explaining imagination [...]"!  After all that work, Descartes in the next line decides that this is not definitive proof of his having a body but it is "only a probability".  So, how then can we prove the existence of the body, and other bodies for that matter?  The suspense is killing you, I know!

Argument 2  Argument for the Existence of Body From Sensory Perception

     When we began the whole skeptical enterprise we used several arguments (dream/evil demon/fallibility of the senses) to call into question the information we derive from our senses our bodies (that I have vascular arms, a strapping chest, chiseled abs, etc...) and other bodies, so how might appealing to sensory information help us in proving we have a physical body?       

     We begin with some observations about sensory information:  a) through sensory perception we have a clearer and more distinct impression of the modes of Body (primary ones as well as colour, scent, pain, etc...) than we do with our imaginations; b) the ideas which enter my mind via sensory perception are recalcitrant to my will (I cannot will them to go away, to change, or to appear);  c) I can never separate myself from the body that I call mine; d) I feel all my appetites, emotions, pain, hunger, thirst because of (what I perceive to be) my body.

     In regards to (d) how can I explain that I feel sensation in the body I call my own but not in bodies I don't call my own?  This may seem like a silly question but it actually brings us to an important issue regarding the location of sensations--specifically secondary modes of Body.  And, surprisingly (?), the solving of this quandary will help us with our argument to both prove both the existence our own bodies and other "object" bodies.  

     First Descartes repeats that the different modes (properties) of Mind only pertain to thought and ideas and the different properties of Body only pertain to body.  From this premise we can reason that the causes of my ideas that arise out of sensory perceptions must be either a substance that is Body or it must coming from God.  This is because Mind does not, by definition, have the properties (modes) of physical things...and presumably God can do or be whatever he wants (Duh!). 

     But how are we to know if the source of our sensory perceptions are God or corporeal objects?  Soooooooo simple.  You see, we know 2 things: that sometimes our senses deceive us, and that god is not a deceiver.  Since god is not a deceiver "it is quite clear that he does not transmit the ideas to me directly from himself, or indirectly, via some creature which contains the objective reality of the ideas [...]".  If god were transmitting to me directly from his control tower in outer space there would never be any mistakes because god is perfect and, furthermore, would not deceive us (even though he could if he wanted too...that rascal!).  Therefore corporeal things exist.  Git it?

     This seems a good a place as any to take a break and let y'all digest those mind blasting arguments.  The next entry I want to focus on Descartes explanation of pain which is quite interesting and raises a lot of issues about the nature of consciousness.  By the by, I apologize for the haphazard uses/interchanging of Body/Extension and properties/modes.  I hope it didn't cloud things too much.  Descartes uses Body and Extension interchangeably and he usually uses "mode" in lieu of "property".  They mean the same thing but there is a reason why Descartes avoids using "property".  In the Aristotelian framework they used (because academic work was all in Latin at that time) "proprium" which is the root of the English "property".  In order to avoid readers conflating the two models he used "mode".  There you go.  Nice little lesson in Etymology on top of an entry about Descartes.  I'm just too good to my readers!

To my Philoso-friends, please correct me where you think I have misinterpreted arguments...thanks