[(edit) since the original post to which this was a reply seems to have vanished, i'll reconstruct the questions put forth.]
psyT: that is not foundationalism; and even descartes in his first meditation deems 1st person sensory knowledge as uncertain.
&
psyT: i think you are confusing 'some other world' with 'this world' in your modal fictionalism.
allright, i'll try to clear it up.
my reference to foundationalism is there to make it easier to comprehend. foundationalism has no logical basis by its own. as you note yourself adamantly with descartes first meditation, solipsism can never be ruled out logically. which is the only true foundation.
dubito, ergo sum. paradoxically though, it is not a foundation (for
truth). its a bottomless swamp.
therefor, i refer to such a foundation (of truth) as a modal foundation in first instance. it has the possibility of being a foundation. so it is both a foundation and it is not at the same time. this position i refer to as modal fictionalism. while the possible world wherein this is a foundation is not true, the benefits of it can be kept by the subject, eg. by his belief in the fiction; it creates very real effects in the very real world. here we come into the grey area in between (and why it bears reference to foundationalism). although it is a fiction, said person acts on it
as if it is true. say he blows himself up as a suicide bomber. the world in which these effects manifest is the interpersonal world. thus by way of their effect, the modal foundation gains a level of reality through the subject taking it as a foundation (while it is not, stricly speaking). this is the grey area
lets now cross over into true inter
personality (in the previous example, the other persons affected have no free will in the matter, and are thus objects). the truth as something that extends beyond ourself is not established.
say you experience a (mystical) state wherin you come to see your significant other as your true soul mate. you are led to truly believe this. this is your personal experience. by the power of your sincere belief in it, it becomes a foundation (for you); personal feelings and thoughts are built on it (note that descartes does the same thing in his cartesian circle). however, from the perspective of the interpersonal realm; this is only a modal foundation. it is possible. here we cross the grey area. so the next day you are cuddling with your s/o, you tell her of your experience and feelings. here the
modal foundation
may become a truth in the sense of 'beyond myself'. suppose your s/o says YES, i also feel such a thing. the modal foundation becomes coherent through external factors. though strictly speaking there still is no
objective foundation, it becomes a true foundation by the means of this coherence. eg. both you and your partner will act accordingly and produce real effects in the shared world, coherent with your belief. thus these 'objective' effects lend a level of reality to the cause of these effects; ie. what once was the modal foundation. infact, an instance such as the cartesian circle is here created: the belief becomes a reality through its effects, which in turn reinforce the belief further, making its base broader/stronger everytime the belief is confirmed. we gain trust in it, and begin building upon said belief, forgetting, as a matter of fact, that it is actually a belief. this is infact a foundation as it is used in foundationalist theory. it doesn't get any better or stronger then this. which means foundationalism cannot exist without a reinforcing coherentism.
and for the apotheosis: the foundation of the scientific method; eg. experience/experiment is no different whatsoever. One notes A is causally connected to B. one notices similar situations in which this is true. one concieves of a general theory that as broadly as possible encompasses all these events. however, as strongly confirmed the theory will get, in
actuality it never passes into objectivity/ beyond hypothesis. that is a leap
we make. you can never have experienced all possibilities of said theory. Though incredibly small, there is
always the chance that suddonly a situation pops up that contradicts the theory. when that happens, the theory is either discarded or amended. so its never truly objective. you say a pure science like mathematics? axioms!
modal fictionalism, broadly taken, is a way by we can designate the fiction of our foundations, while at the same time take them for real through their effects. as a philosophical position, we can keep the benefits of these fictions, while escaping universal foundationalism which is either a bottemless-pit-paradox or completely untenable in terms of epistemology. when taken not too narrow, modal fictionalism is philosopically speaking a very tenable position regarding avoidance of paradoxes in most fields applied. its not perfect though (as if, lol
)
[wanders off talking to the birds and the trees]
)