Re: Epistemology 201: The Science of Science

From: Daryl McCullough (stevendaryl3016_at_yahoo.com)
Date: 03/24/05 

Date: 23 Mar 2005 16:17:02 -0800

Lester Zick says...

>>My definition is a definition in the same sense as the
>>following definitions
>>
>> x is even <-> x is an integer, and x is a multiple of 2
>>
>> x is a prime number <-> x is an integer, and x > 1, and
>> there does not exist integers y and
>> z such that y > 1 and z > 1 and y*z = x
>>
>> x is a perfect square <-> there exists an integer y such that y*y = x
>>
>>etc.
>>
>>These are definitions, in the sense that they explain the meaning of
>>a defined concept (on the left side of <->) in terms of concepts that
>>are already assumed to be understood. The definition of "infinite" has
>>exactly that character:
>>
>> x is infinite <-> x is a set, and there exists a set y that is a
>> proper subset of x such that there exists a bijection
>> between x and y.
>
>Well I agree, Daryl, except what you seem to be defining is x under
>various conditions.

No. x is a variable. What is being defined is the *predicate*
x is even, or x is a perfect square, etc. 

--
Daryl McCullough
Ithaca, NY

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