two abductive syllogisms

a formal [[EDIT 11/30: not formal, but CRITICAL]] analysis of two abductive arguments:

first, the creationists' argument for god from intelligent design.

(a) there is this universe which is gloriously complex (assumed)
(b) if god exists, there would be this universe which is gloriously complex (assumed)
(c) god exists (aim)

now as philosophers we have to define god. let's take the christian one, an omnipotent, omniscient, omnibenevolent one. the idea is that only god could design this universe.

now the proper inquirer not only has to draw consequences of god existing, (there's lots of negative evidence. anything from the earth being created longer ago than several thousand years, to the fact that a triple O god would not allow for natural disasters, war, or just insert whatever evidence against god you like), but also notes that (1) it's completely unnecessary for explanation of the universe's complexity (this is where natural physical law and evolution come in) and (2) it wouldn't cohere with the rest of the scientific picture of how the world works. (1) and (2) are the epistemic virtues of parsimony and coherence.

now, because there are arguments against god's existence, because god existing is unnecessary to explain the complexity of the universe, and because it wouldn't fit in with the rest of the evidence we have about the world, that makes three strikes, the abduction is an invalid one. so, what does this finally prove? this proves that a christian god cannot explain why the universe is beautiful and complex and all that good stuff.

now, to the objective reality/scientific realism argument.

(d) science works. (assumed)
(e) if there's a world out there independent of what we believe, then science would work. (assumed)
(f) there's a world out there independent of what we believe. (aim)

now let's draw some consequences of the antecedent and its negation, just as before. first, draw consequences from (f). there is evidence for reality being independent of what we believe of it as we see through everyday experience (this is the positive evidence bit). it fits in with the rest of our knowledge about the world (the coherence bit). and finally (f) is actually necessary to explain how science works so it is as pasimonious as it's going to get.

now of course i owe an account, a reason as to why it's necessary for there to be a real world independent of you and i to explain that science works. this is easier than it seems. if you never lived, would there still be trees? whether or not anybody ever got to investigate genetics as far as we have, or whether scientists thought it was 48 chromosomes before and think it's 46 now (and change their minds tomorrow), is there a right answer as to how many chromosomes we as humans actually have? if i never went to argentina, would it still be there? the answer to all the questions is yes, and as such give evidence to the contention that in there are bits of reality out there about which we can both state propositions and be causally independent of any individual's beliefs or existence. ultimately, in order to fully investigate the answer of these questions (as a scientist does), then there must be something that you're investigating, otherwise it's just subjective musings.

but now, to be more thorough and fair , let's draw some of the consequences of -(f) [the negation of the conclusion]. -(f) does have an advantage over (f) in its being more barren. but it directly contradicts experience. let me fully illustrate this point:

(1)if there is no world out there independent of what we believe it to be, it follows that the world does depend on what we believe it to be.
(2)some jellyfish are poisonous (i got stung by one last... year, i think?)
(3) but for some jellyfish to be poisonous, then jellyfish must exist whether i think them to exist or not, and being poisonous must be a property that exists whether i ever get stung or not.
(4) but, as constituents of this belief-dependent world, jellyfish being poisonous does depend on my beliefs after all.

(3) and (4) are contradictory, so -(f) does not cohere with the rest of what we know about the world and leads to logical contradictions. and lastly, we have overwhelming evidence against there not being a real world, as with every day of our lives we get in our cars and go places, hug our families, use computers to communicate with other individuals across the country, etc.

(f) has positive evidence, it coheres with our knowledge, yet it does posit more causally necessary entities than

-(f), which is more parsimonious is TOO parsimonious, because then we wouldn't have enough epistemological base for any inquiry of any kind, whether it's a scientist hypothesizing quarks or the layperson trying to figure out how to fix his bike. Furthermore, -(f) has negative evidence, and it does not cohere with experience.

so the abductive syllogism of (d-f) is very well supported a vast amount of positive evidence.

so what does this show? well... it shows that based on the best evidence we have so far, there is a real world out there independently of what we believe. the alternative is that science is just another legitimate dialogue among many, yet could ultimately be dealing in fictions, which (1-4) shows is inconsistent.

also notice that, in order to consider these (and any) abductions, you need go go through the formal process of logical analysis, the pragmatic process of drawing manifested effects of propositions (consequences), AND the external process of empirical investigation.