Change has been thought of in several different ways throughout history: What is change? Is change even possible? How so? etc. The more one ponders such a notion the more abstract and odd it becomes. Thinking about change one says to themselves change is not A becomes A (A-->A), that is only continuity and no change what-so-ever took place, so change must occur when A becomes not A (A-->Not A). Though herein is something weird - does the object, A, exist, disappear and then get replaced by something else, Not A or does A somehow morph into Not A? If the former case is true and at every moment things exist, disappear and then are replaced, then there are gaps in time where things do not exist and everything is flux as well as only partially existing - this makes absolutely no sense, there cannot be a moment when something exists followed by a moment when it does not, followed again by it existing. The only way that this could make sense (and it still does not) is if the object went from this world to another and then back, so rather than disappearing and being replaced it simply goes somewhere else and comes back, changing both its spatial and temporal location, but still essentially remaining the same. But, if the latter is true then things must be somewhat ambiguous if they are to be able to be themselves enough to be recognized, but not themselves enough to have any semblance of change take place. After several people put in their opinion and after several years of Socrates forming his own opinion he thinks that he has an answer to this problem.
Initially, philosophers attacked the problem of change by making everything equivalent to the "elements", earth, air, fire, water, but one at a time, e.g. one guy said that the whole world is water, another fire, etc. Finally there comes a time when people realize that even if all things are made of the same element, say water, that that still does not do justice to the problem of change because even if everything is water that water still needs to be itself and not itself simultaneously in order to change and yet still retain some of its identity. After this philosophers tackle the problem a little differently first by saying that everything is constantly changing and is thus completely ambiguous, then by saying that nothing actually changes and everything is just an illusion. Then Socrates comes onto the stage and smashes these two notions together and comes up with a better answer to the problem of change than all others before him.
Plato, using Socrates as the mouthpiece, spouts an answer to the problem of change with a counter-intuitive reason by saying that sensible objects are and are not what they are simultaneously. At first this seems entirely ludicrous, but after a careful examination ... well, seems a little less unlikely. Before Socrates were a set of philosophers dubbed "the Pre-Socratics" as if Socrates is all powerful, amazing and wise and not still bound to the somewhat typical position of a philosopher as combiner of two schools of thought - as well as no one is an island and these Pre-Socratics definitely influenced Socrates. . Regardless, the two most relevant of these Pre-Socratian philosophers are: Parmenides and Heraclitus. Both of these philosophers had an answer to the problem of change that is both like Socrates' answer and not like it at the same time! Weird.
Heraclitus believes that everything in the world is eternally flux and felt that one can "never step in the same river twice". To Heraclitus change is a unity of opposites; something has to be itself and not itself at the same time. Simply put, for object "A" to change it has to become "Not-A". Thus "A"-->"A" is not change, only continuation of the same; however, "A"-->"Not A" is change, but "A"|"Not A" is simply replacement (pending one's ability to pretend that | = a lapse of time containing nothing after A disappears, but still before it is replaced by Not A). Also, when something is itself and not itself simultaneously, it is equally itself and not itself - like a vertical line is both up and down simultaneously. Thus, in order for things to change they have to be objects that are ambiguous enough to be themselves and not themselves simultaneously. So for him, the basic structure of the universe is ambiguity because everything is able to undergo change and change requires something ambiguous unifying the opposites; if the world is a world of change, then it must be ambiguous, otherwise change would be unable to transpire here.
Parmenides believes the opposite and thinks that logic is the ultimate arbitrator of the universe and when a person is stuck between logic and anything else, even experience, they should choose logic. To him change is an illusion; there is no such thing as change - though we can "experience it", that does not stop it from being completely illogical and wrong, according to him. He says that there are two things a body can try to investigate: what is or what is not. However, Parmenides thinks that it is impossible to investigate what is not because what is not is nothing and a person cannot investigate nothing - you would end up with a sentence like this: "I am going to investigate (nothing)". And he is right, it is hard to construct a sentence without a predicate let alone legitimately perform an action on something that does not exist. So Paremenides says, how Heraclitus attacks the problem of change is illogical. It is absurd to think that what is and what is not are the same and not the same at the same time. Parmenides believes that when Heraclitus says things are and are not simultaneously really he is saying: what is not is and that is illogical - it is like saying: what does not exist does exist. And Parmenides continues to say that when someone makes this mistake they are treating nothing as something. He says that there are four qualities that make up anything that is: 1) it is uncreated and imperishable; 2) it is univocal and unambiguous; 3) it is unchangeable; 4) it is perfect. What is is uncreated and imperishable, he says, because what is always must have existed otherwise nothing would exist, if what is is not then nothing is - simply put: the time before everything existed was nothing and no time and the time after everything existed is also no time. Graphically it looks like this: |What is not-->What is-->What is not|. He says that what is is unambiguous and univocal because it is illogical to think that what is is and then for there to be moments when nothing exists (|something{nothing}something|) makes no sense because this again is the faulty notion of replacement; Parmenides says that it must be like this: |everything| otherwise there would be moments when things existed and then moments when they did not and any period of nothing between two somethings is still nothing and nothing is still unable to be something. Finally, he says that what is is perfect because the world lacks nothing, what is here is here and anything that is here has always been here and always will be here, until there is nothing and in that case then there is literally no-thing to comprehend.
After these two Socrates too torments Greece with his insights, but instead of just arguing with concedes to both and argues with them at the same time. Socrates says that there must be two worlds: the intelligible world and the sensible world. These worlds are independent of each other and necessary. The intelligible world is a non-temporal and non-spatial place that contains "the forms". These forms, which contain all of Parmenides' qualities of things that are (imperishable, unambiguous, unchangeable and perfect) are objects that all of the lesser objects of this world are based on - they contain only properties that make them what they are (called essential properties). These forms are unique and perfect versions of wide categories of things, e.g. cats, houses, dogs, chickens, chairs, grass, etc. Socrates believes that prior to our birth we exist in the intelligible world and our soul learns of the forms and then we are born - to him without this previous knowledge we would be unable to tell things apart on Earth. Earth, or where ever we exist as "alive", however, is called "the Sensible world" - obviously, the one we perceive through our senses. This sensible world is full of things that are what they are (containing the essential properties of the form) and are not what they are (containing accidental properties - properties that have nothing to do with the form). So, whenever one thinks of instances they should think: conforms to all the necessary elements of a form (essential properties) + has other properties (accidental properties). However, though a distinction should be made: even though it seems to our American "more is better" attitude as if sensible objects are better because they have more than simply the elements of the form, Socrates thinks that they are actually deficient variations of the form because they have things that make them less like the form. This distinction allows sensible objects the ability to be like Heraclitus' notion that the world is made of ambiguous things and are thus able to change. So all Socrates is really doing here is saying that both Parmenides and Heraclitus are correct - as Parmenides said, there must be a world of perfect, unchangeable, unambiguous and uncreated objects, the intelligible world so that in this world of experience we are able to discern the difference between say vice and virtue; however, Socrates is also saying that on this world there must be ambiguous objects as well because otherwise change is completely impossible. So for Socrates things of this world necessarily are and are not what they are simultaneously, but only in the sense that they embody the form (are like the form) and have accidental properties (are not like the form), the parts that remind you it is a crappy rip-off of the form, kind of like how the less satisfactory taste of generic food products reminds you that it is not the product it emulates, forget that it is a somewhat bad example because both food products are instances of whatever it is, say cake.
Socrates says that change is possible only because of this two world metaphysics. Also, to Socrates change is only possible in the accidental properties of a sensible object and not at all possible in a form. Thus when a sensible object changes it both stays the same (the essential properties are the same) and it changes (the accidental properties become different). Take for example a ball - it has a set of essential properties that make it a ball, e.g. spherical and a set of accidental properties that make it an instance rather than the form, e.g. location, color. If I roll it across a table its location changes, but it is still a ball and the same ball in fact. So what Socrates is saying here is this: object X (has accidental property A) ---> X (no longer has property A); a dog house (object X) is blue (A), until I paint it black (Not A), but is still a doghouse and the same doghouse in fact. Though, this does not do complete justice to the problem of change, it is better than Parmenides and Heraclitus' answers. Socrates also realizes that there has to be more to change than that because, take for example a wooden chair, starts as a tree, is chopped down and then is turned into usable wood. After that the wood is specifically changed so that it can become a chair. After a while the chair becomes unwanted and someone throws it into a wood chipper, chips it and then sets the chips ablaze. What about it changed? It started as a tree (which contains the necessity of it being wooden) then becomes a wooden chair then a pile of wood chips and finally a fire. This is only possible because the tree is an object that is capable of being all of those things, if it were not, then it could have only been some and not others. Though it embodies several different forms (tree, wood, tree, pile of chips) as a mere instance throughout its "lifetime", it is non-the-less still wood and wood must be an object that is capable of ambiguity. Which is why it is able to make all of those changes. To make sense of this type of change Socrates says that forms give objects a purpose which is to become more like the form. At first the tree is trying to be the most tree-like it can, until it is cut down. Once down it tries to be the best plank of wood, then the best chair. Then when the chair is tossed in the wood chipper it becomes a deficient chair (loosing the accidental elements and becoming essentially deficient simultaneously) until it is no longer a chair and then works toward being the best pile of chips possible. So for Socrates, there are three kinds of changes that can take place regarding an object - the first is that the accidental properties change without effecting essential properties, second accidentals decrease and that decrease decreases the essentials (the chair goes into the wood chipper and looses the qualities that made it a chair), the third is that the accidental properties change and that change improves the essential properties and the object becomes more like the form (the chair is refurbished and made more comfortable and sturdy).
Change is a necessary element of our world and though it is likely still not completely understood, had Socrates not made sense of it we could still think that change is an illusion. Probably not, most likely there would have been a Tocrates or something to take his place, but regardless, he gives us an amazing start from which growth is inevitable by combining philosophers from the past. Heraclitus gives us the notion that things must be ambiguous to change, but Socrates notes it is ludicrous to think that everything is completely ambiguous, in that view objects of the world lack self-identity and everything is completely unique. Parmenides is also wrong because if everything were self identical, not only would there only be one type of thing (what is as all the same thing), but nothing would ever happen. And, says Socrates, things need to have identity (Parmenides), but be ambiguous enough to allow for change (Heraclitus). So he says that sensible objects get their identity from perfect, unchangeable, permanent objects called "forms" as well as possess qualities that make them unlike the forms as well. Thus, the problem of change can be answered like so: sensible objects are only able to have identity because the objects conform to pre-existing forms. These sensible objects also have accidental qualities that are not included in the form. Change takes place in the accidental qualities only and in the case of an object changing so much that it no longer is an instance of the form, its accidental qualities are changed to such a point that it is no longer an instance of the form and becomes a different instance of a different form altogether. Thus, objects can change, but still remain the same as long as the change is only in the accidental properties either completely ignoring the essential properties, or in changing the accidents in such a way that they are either more or less like the form, which sometimes leads to the object becoming an instance of a different form.
