Material Differences Between History and Nature 
	Andrew P. Porter

Abstract: 

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The paper finds at least nine material differences
between acts in history and entities in nature.  

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(1) Nature rules out intentional structures essential to human acts.

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(2) Material trajectories in nature are unique,
but acts in history are open to multiple interpretations.

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(3) In terms of set theory, 
history is bigger than nature. 

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(4) Historical acts cannot be demarcated from the rest of the world
by interactions with the world at a boundary.

What happens far off-stage can transform human acts in focal view.

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(5) Human acts can be revised after the fact.  
Material trajectories in nature cannot be.

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(6) Meaning and interpretation are constitutive of human acts.

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(7) Human acts may involve physical motions;
they do not always. 

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(8) Human acts always involve final causes.

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(9) Efficient causes in nature determine their effects;
efficient causes in history may not.