The Same Thing In Plato's Argument

The principle stated at 436c, that the same thing cannot do, be or undergo opposite things in the same respect, in relation to the same thing, at the same time is a basic premise in Plato’s argument. This principle supports the conclusion stated in 439c, that if we are thirsty and rejecting the drink at the same time, there is something in the soul urging us to drink and something different stopping us. At first, I am going to reconstruct the argument, then try to show how the argument works, and why this principle is so important. The argument is:

P1 The same thing cannot do, be or undergo opposite things in the same respect, in relation to the same thing, at the same time.
P2 If opposite things are done in the same respect, at the same
time, they must be done to different things.
P3 If the same thing is doing or undergoing opposite things in relation to the same thing, at the same time, it must be in different respects.
P4 Wanting something and rejecting it are opposites.
P5 Thirst is wanting to drink .
P6 If someone is thirsty it is her soul that wants a drink, and if someone is rejecting a drink it is her soul that does not want it. (C)
P7 Sometimes we are thirsty but rejecting the drink. Therefore, there is something in the soul urging us to drink and something different stopping us.

P3 is a conclusion from P1 and P2, as it is possible for one thing to do opposite things at the same time in relation to the same thing only if it does it in different respects. Opposite things can be done in the same respect at the same time if they are done by different things or in relation to many things. And if opposite things are not done at the same time, there is no problem. But if there is only one thing and opposite things are done to this thing at the same time by one and the same thing, the only possibility left is that these opposite things are done in different respects to the thing. «…if anyone said of a person who is standing still but moving his hands and head, that the same thing is moving and standing still at the same time, we would not consider, I imagine, that he should say that; but rather that in one respect the person is standing still, while in another he is moving.» If the same person has an appetite for a drink and is rejecting it at the same time, we cannot say that she is wanting it and not-wanting it in the same respect, she must do it in different respects. And there are two possibilities: to do it in different respects of herself or in different respects of the drink. P5 says that thirst is wanting to drink, it says nothing about the kind of the drink the person might want. The person is thirsty, which means, that her soul has an appetite for something drinkable, this appetite is not for a particular drink, any drink will be fine for her. To be drinkable is reason enough to be wanted by the thirsty person. It is impossible for the person who has thirst itself not to want a drinkable thing. Since drink itself cannot be good or bad or have any other characteristics, which could be important for the person, who is wishing to have something drinkable, it is not possible that the person is doing opposite things in different respects of the drink. If the drink had those characteristics, we would have to admit that person’s thirst is for a particular drink and is not thirst itself anymore, for thirst itself may be only for drink itself. If I am accepting and rejecting the same drink at the same time and do it in different respects of the drink, there must be something in the drink that I am rejecting. And in respect of that something in the drink I do not want that particular drink. But as anything drinkable is good to still thirst and my only wish is to get a drinkable thing, there can be nothing in the drink that I will reject, because then I will have a particular thirst. «Thirst itself, however, is not for much or little, good or bad, or, in a word, for drink of a particular sort; rather, thirst itself is, by nature, just for drink itself.» And as the person in the argument has no particular thirst but thirst itself, there is nothing in the drink, that can be a reason for not wanting it. Even if it is poisoned, as long as it is drinkable the thirsty person is wanting it, because if she is not, she has a thirst for a drink that is not poisoned, which is a particular sort of drink, and wanting it is a particular sort of thirst. As the person has thirst itself and cannot be rejecting the drink, she must be wanting it as long as it is drinkable. Her soul cannot be wanting and not-wanting with different respects to the drink. Still these opposite things must be done in different respects of something, because they are done at the same time in relation to the same drink and by the same soul. Hence, it seems right to conclude, that the soul is doing opposite things to the same drink with different respects to itself. In the text, several examples are given, which help to understand the idea of different respects.
One of the examples is the archer, who draws the bow toward himself and pushes it away at the same time. Another one is the spinning top, that seems to be moving and standing still at the same time. According to P1 none of this cases is possible if we assume, that opposite things are done in the same respect. So, we apply P3 and say, that in these cases opposite things are done in different respects to the archer or spinning tops. To make it possible, that something is done in different respects of the thing itself, it seems to be right to distinguish different elements of the thing. So, if the archer does opposite things in relation to the bow at the same time, we must distinguish his two hands, one pushes the bow away and the other draws it toward him. Just the same happens to the spinning top. To say that the spinning top is moving and standing still at the same time in the same respect of itself contradicts P1; so, here again, we have to distinguish two different things within the spinning top, in respect of which opposite things could be done. That is why we say that the same spinning top has a straight axis and a circumference. With respect to the straight axis, it stands still, while with respect to the circumference it
moves. If we apply the same principle to the soul, which is accepting and rejecting the same drink at the same time, but is doing it in different respects of itself, we need to distinguish two different things in the soul. In respect of one of them it is accepting the drink and in respect of the other rejecting it. One of the things is something, that in this case urges the person to drink, and the other one is something, that stops her. If we look at the structure of the argument without the principle stated at 436c, and P3, that follows from it, it seems, that we could make only the following conclusion: sometimes we are doing opposite things at the same time in relation to the same thing. However, the goal of Plato’s argument was to show, that there are different elements in the soul, which sometimes are doing opposite things in relation to the same thing, at the same time. To show it another premise was needed. And this premise is the principle stated at 436c.