Newton - Leibniz - Absolute Time
We'll start with the concept of absolute time as i think that is easier to explain.
What is important to understand in the Newton-Leibniz debate about absolute time is that Leibniz did not refute Newton's conception, he was refuting the commanly understood meaning of Absolute Time at the time. Newton had, however, redefined the term.
Newton realized that if phrases such as "sweep out equal amounts of space in equal amounts of time" were going to be meaningful, space and time were going to have to be defined as constants and, really, he doesn't mean much more than that we he speaks of them as absolutes.
The general meaning of absolute space and time at that time would be for everything to have a fixed coordinate on a grid, bit in space and in time. Leibniz attacked this conception as meaningless and he used the notion of the Identity of Indiscernables to make this attack. Time, to Leibniz, was just the sequence, there were no coordinate points. He would say something like ... imagine two universes in time with everything the same except in one of these universes everything happens 10 seconds before the it does in the other. Well, since there is no way to tell these universes apart the concept of Absolute Time as something like extension with coordinates is meaningless.
Newton had zero problems with this argument. That is simplay not what he meant by Absolute Time.
Newton tied his concept of Absolute Time to his physical laws, namely, to inertia. The definition goes something like this. Two bodies are moving through space with the same velocity. In the same amount of time (sequences) they will always move the same distance. If a force is applied to one of the bodies to speed it up, that body will now always cover more space in the same amount of time (sequences).
Time is here also just the sequences. The absolute sense of time is that these sequences occur at a standard rate. Further, this is true if the objects are side by side, across the universe from one another, or even a trillion time sequences removed from one another.
Now ... absolute time is still problematic from our point today even thus defined, but it was not considered problematic. Kant would have accepted it 80 years later and both the Newtonian and Leibnizian camps would have accepted the concept (though they would probably have called it by different names) at Kant's time.
When Kant moved from one camp to the other, then, really, he was just changing his definition of absolute time from the old Cartesian notion to the notion tied directly to Newton's Laws of Motion.
For someone to attack this idea of absolute time, then, they must say that one of Newton's Laws of Motion is wrong (inertia) or they must add one or more Laws of Motion that have an affect on the defition. (The later being the case of what Einstein did do.)
So ... that is the state of play of the concept of Absolute Time as thought of by Kant at his time. I'll handle space separately as it is more problematic. Newton's Absolute Space, however, is going to derive from the same impetus ... the defining of space by tieing it to the Laws of Motion.
What is important to understand in the Newton-Leibniz debate about absolute time is that Leibniz did not refute Newton's conception, he was refuting the commanly understood meaning of Absolute Time at the time. Newton had, however, redefined the term.
Newton realized that if phrases such as "sweep out equal amounts of space in equal amounts of time" were going to be meaningful, space and time were going to have to be defined as constants and, really, he doesn't mean much more than that we he speaks of them as absolutes.
The general meaning of absolute space and time at that time would be for everything to have a fixed coordinate on a grid, bit in space and in time. Leibniz attacked this conception as meaningless and he used the notion of the Identity of Indiscernables to make this attack. Time, to Leibniz, was just the sequence, there were no coordinate points. He would say something like ... imagine two universes in time with everything the same except in one of these universes everything happens 10 seconds before the it does in the other. Well, since there is no way to tell these universes apart the concept of Absolute Time as something like extension with coordinates is meaningless.
Newton had zero problems with this argument. That is simplay not what he meant by Absolute Time.
Newton tied his concept of Absolute Time to his physical laws, namely, to inertia. The definition goes something like this. Two bodies are moving through space with the same velocity. In the same amount of time (sequences) they will always move the same distance. If a force is applied to one of the bodies to speed it up, that body will now always cover more space in the same amount of time (sequences).
Time is here also just the sequences. The absolute sense of time is that these sequences occur at a standard rate. Further, this is true if the objects are side by side, across the universe from one another, or even a trillion time sequences removed from one another.
Now ... absolute time is still problematic from our point today even thus defined, but it was not considered problematic. Kant would have accepted it 80 years later and both the Newtonian and Leibnizian camps would have accepted the concept (though they would probably have called it by different names) at Kant's time.
When Kant moved from one camp to the other, then, really, he was just changing his definition of absolute time from the old Cartesian notion to the notion tied directly to Newton's Laws of Motion.
For someone to attack this idea of absolute time, then, they must say that one of Newton's Laws of Motion is wrong (inertia) or they must add one or more Laws of Motion that have an affect on the defition. (The later being the case of what Einstein did do.)
So ... that is the state of play of the concept of Absolute Time as thought of by Kant at his time. I'll handle space separately as it is more problematic. Newton's Absolute Space, however, is going to derive from the same impetus ... the defining of space by tieing it to the Laws of Motion.
posted by Thomas F. Schminke at 8:07 PM
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"You see, wire telegraph is a kind of a very, very long cat. You pull his tail in New York and his head is meowing in Los Angeles. Do you understand this? And radio operates exactly the same way: you send signals here, they receive them there. The only difference is that there is no cat."
- albert einstien
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