Subject: 
        [evol-psych] 'oughts' & 'is'es
   Date: 
        Tue, 19 Feb 2002 12:00:41 -0000
   From: 
        "Jack Parsons" 
     To: 
        "evolutionary psychology" 




Dear colleagues,
                                Half of my degree was philosophy * but that was fifty years ago so it is with some
trepidation that I now express my puzzlement -- not to mention a degree of irritation -- that this debate
meanders on and on without a single hint of recognition of formal logic (an iron discipline?) or its main rules
and concepts: universe of discourse, deduction v. induction, propositions, forms, symbolism, individuals,
classes, major & minor premises, syllogisms, corollaries, validity, connotation, denotation, proof, etc.
 
Surely all members of the list must know the famous traditional syllogism:
 
1) All men are mortal
 
2) Socrates is a man
 
3) Therefore Socrates is mortal
 
In the absence of the major premise; 'All men ...' , it is formally illegitimate to deduce that 'Socrates is
mortal',  and this particular major premise came --  and could only come --  from induction, not deduction.
Although it is true that all three propositions here are 'is'es, surely the general form must also apply to
cases of 'is'es & 'oughts'.
 
To take a contemporary example of some consequence; it is not logically permissible (getting an 'ought'
from an 'is') to deduce from the minor premise:
 
'Ruthless terrorists have attacked and destroyed the World Trade Center with massive casualties.'; that:
 
'The Free World ought to unite, counter-attack and bring to justice (destroy?)  these terrorists and all who
support them, whoever they are wherever they are located.'  
 
In the absence of a preceding (and true) major premise (such as; 'The Free World always bands together to
defend itself against terrorist attacks', an 'is') this 'deduction' (an 'ought', which may or may not have a lot
going for it) is logically invalid.
 
The possible major premise just stated is obviously untrue so perhaps we need a different one, eg 'The
Free World ought  to band together ... etc'.  But then we immediately come up against the problem of
justifying this 'ought' , which again, cannot be obtained from any number of 'is'es without a process of
induction. Logical deduction will never do the trick.
 
Ergo: 'oughts' can never be rigorously deduced from 'is'es.
 
QED?
 
Best wishes to all. Jack P.
 
* The other half was Political Science.
 
 
 
Jack Parsons
Former lecturer, Brunel, Cardiff, & Exeter universities.  Occas. consultant to BP, IPPF, IUCN, OXFAM, &
other bodies.  Advisory ed. Population and Environment.  Memb. Population Working Group;  Hon. Adviser,
European Pherology Organisations Confederation (EPOC). Hon. Associate, The Rationalist Press
Association.Hon. Life Memb., Centre for Alternative Technology (CAT); Patron, The Optimum Population
Trust
 
Main Pubs.:
(2002)  An updated 4th edition of the 1998 book (below) will be soon be published in interactive form on
CD.    
(2000) The Reverend T.R. Malthus. Demi-devil, Saint, or Merely Great Benefactor? A Cardiff University
monograph.
(1998) Human Population Competition. A Study of the Pursuit of Power Through Numbers. 2 vols. Orig.
pub. by the Edwin Mellen Press 
                                                                                                                                                                           of Lewiston,
NY. (Out of print since 2000)
(1977) Population Fallacies. London. Pemberton/Elek.
(1971) Population Versus Liberty. London. Pemberton Books.
Last two still in print, copies avail. fr. author.