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Re: "running" elephants - locomotary analoges



HP Philidor wrote... 
 
> Using an example from the discussion, a conclusion that pterosaurs 
> above a certain size couldn't fly would be based on general principles, 
> but the material of which the bones were made is unknown. 
  
While it is unknown to a certain degree (we can test if the mineral is  
hydroxyapatite...), phylogenetic bracketing is there to give us an idea  
about what the precise composition of the collagen could have been like,  
and then there are fossils (like the azhdarchid IIRC tibia with a  
velociraptorine tooth in it) to give us an independent idea on the  
mechanical strength of the bone.  
  
> Because part of the material necessary to draw 
> a conclusion is wrong, the result is wrong. 
 
Sure. 
 
> Which is an elaborate way of saying garbage in, garbage out.  
> A problem will arise when there exists a set of self-consistent  
> speculations which happen to be factually wrong (if observations could 
> be made). In that case, a whole range of different approaches to a 
> problem using subsets of those speculations will produce consistent 
> results, apparently confirming the speculations. However, all that will 
> actually be confirmed is that the erroneous speculations are logically 
> consistent.  
> Consistent garbage in, consistent garbage out. 
 
However, the more garbage we put in, the smaller the probability that it 
will be consistent. The larger the set of speculations, the higher the 
probability that one will contradict others. 

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