|
p.xi "Dr. Livingston, I presume" runs the famous exclamation with which H. M. Stanley greeted the long lost explorer. And in saying this he as much as said that "this is what I am going to take to be the case unless and until further developments should show that it is not." That is just exactly how presumption works... The practice of presumption arose initially in law but subsequently became operative in virtually every area of rational endeavor, for presumption is a remarkably versatile and pervasively useful resource.
xii as this book's deliberations endeavor to show, the process of presumption plays a role of virtually indispensable utility in matters of rational inquiry and communication.
p.1 What Presumption is All About... There is nothing modern or cutting-edge about it: it is one of the oldest tricks in the book.
[JLJ - Rescher is nearly aligned with my thinking that cognition is all about 'tricks that work.' Rescher is flummoxed by presumption because he does not speak, in my opinion, to the two primary uses: 1. As a method of wise action when confronted with missing information and the need to "go on", and 2. As a creative technique to indirectly focus attention, perhaps to continue an argument, or to further an investigation. Specifically,1. avoids inaction or foolish action, and 2. avoids drifting without a goal. Rescher avoids discussing strategy, best practice and case study topics because he cannot give up his (irrational?) love for the idea of rational action. Rescher cannot admit of any use for presumption other than to further rational action, or to arrive at a truth, by way of a 'potential truth'. Note that wise action attempts can backfire, and attention can be focused on the wrong issues. Sometimes in life, you have to come up with a way to "go on" with missing critical information, you have to grasp at things that exist merely to lead you to other things, irrespective of their 'truth' content, and presumption is one way to do this. To operate by means of trial and error, you have to have a creative mechanism that generates the trials which - directly or indirectly - produces insight, and you cannot stop to worry about their 'truthfulness', at the point when they are generated. A 'truth' may at first seem silly, or unimportant, or need a slight but subtle correction, before it is later confirmed to be clearly evident. In playing a complex game of strategy, we have to grasp at the promising moves, and even many of the moves that at first seem unpromising, along with fallback positions and alternate moves, in order to determine practical and useful estimates - diagnostic tests - of our adaptive capacity to mobilize coercion. That is just the way it goes.]
p.1-2 a legal presumption (praesumptio juris) is an inference from a fact that, by legal prescription, stands until refuted. Presumption of this sort is a gap-filling resource: it comes into operation only in the absence of relevant information or evidence, and it leaves the scene once suitably strong evidential indications come to view.
[JLJ - Yes, but it does more: presumption demands that one side in a case construct an argument, or else the ruling will be for the other side. In this kind of situation, one has "nothing to lose" by constructing an argument from whatever one can use to support his/her cause - the ruling is going to be for the other side, so one might as well think up a quick and dirty reason of sorts - anything graspable - to prevent this default judgment. A presumption "works" because it succeeds in generating an argument - which can then be evaluated. If a presumption is not contested by argument, maybe the missing argument, whatever it was, was not strong to begin with.]
p.2 a presumption is not a fact but a provisional estimate of the facts. It is defeasible but nevertheless secure until actually defeated: it remains in place unless and until it is displaced by destabilizing developments.
[JLJ - Perhaps a presumption is/is part of a way to "go on" in the presence of missing information. I prefer to think of it as a stepping stone to a fact, rather than a "provisional estimate" of the facts.]
p.3 there are various sorts of rationales for presumptions... irrespective of their grounding, the operative functioning of presumptions is substantially the same. In every case, a presumption is a plausible pretender to truth whose credentials may well prove insufficient, a runner in a race it may not win. The "acceptance" of a proposition as a merely presumptive truth is not an acceptance at all but a highly provisional and conditional epistemic inclination toward it, an inclination that falls far short of outright commitment.
p.4 Presumptions by nature provide a provisional surrogate for outright claims to the actual truth... A presumption is a tentative and provisional possession of the cognitive terrain, displaced by something that is evidentially better substantiated. A presumption is a putative fact which, while in the circumstances perhaps no more than probable or plausible, is nevertheless to be accepted as true provisionally - allowed to stand until concrete evidential counterindications come to view.
p.5 [footnote] C.S. Peirce put the case for presumptions... as crucial to maintaining the line between sense and foolishness... Peirce saw one key aspect of presumption to revolve about considerations regarding the economics of inquiry - that is, as instruments of efficiency in managing time and money.
p.6 A presumption is not something that certain facts give to us by way of substantiating evidentiation; it is something that we take through a lack of counterevidence... presumption is certainly not knowledge: we do not know what we merely presume to be so... it nevertheless is an informative resource - and a highly useful one at that, since it serves to close up an otherwise debilitating gap.
[JLJ - A presumption lets us "go on" when we might otherwise be stuck. If you are at a party in an unfamiliar house and find that you need to use the restroom, you can presume that a bathroom is near the kitchen or bedrooms, and so proceeding in that general area you can probably bump into one. Now suppose that you have a coughing fit and need a glass of water. Returning to the kitchen area, you can presume that the clean glasses are in a cabinet near the sink, and that if you lift the lever in the sink cold water will flow. All of these presumptions we take and are able to "go on" - if we fail, we can simply ask for directions. The party now over, we return to the curb area for our car and find that the other party guests parked nearby have left space for us to exit to the street by presuming that we would need about 3 or 4 feet space in front of our car. And so on. A reasonable presumption is considered socially acceptable behavior, in the absence of information. In a crisis situation, one cannot ponder indefinitely - one must operate in a mode of thinking and acting that involves 1. generating ideas on how to go on and 2. quickly constructing, executing and evaluating the results of diagnostic tests which look at faint clues which hint or suggest that such a way of 'going on' will be successful or not.]
p.6 Presumptions will vary in point of their probative weight. Some legal presumptions stand until overturned by a conclusive refutation... Still others merely impose a burden of persuasion that reflects a balance of probability... And so there are weaker and stronger presumptions.
p.7 To make out a prima facie case for one's contention is to adduce considerations whose evidential weight is such that in the absence of countervailing considerations, the "reasonable presumption" is now in its favor, and the burden of proof... is now incumbent on the opposing party.
p.7-8 Presumptions are inherently in procedural injunctions... Elsewhere, however, rules of presumption are often mere inference licenses.
p.9 Legal presumption exists to foster the functions of law or the interests of social management. As instrumentalities effective in facilitating public ends they need not directly reflect matters of empirical fact... Presumptions have a life of their own determined correlative with the objectives in whose service they are operative.
p.10 with presumption we take to be so what we could not otherwise manage to establish. And presumptions set the stage for many of our interpersonal actions and activities.
p.11 Law and rhetoric apart, presumptions figure importantly in many other areas of cognitive endeavor.
p.11 Some writers see presumption as merely an action-guiding device. But this does not do full justice to the matter.
p.11 [footnote] "Presumption rules belong to the realm of praxis, not theory. Their point is to enable us to get on smoothly with business of all sorts... to facilitate and expedite action"
[JLJ - Perhaps instead, presumption rules fall into the realm of wise action in the face of conflicting assessments and in the case of missing facts. If we declared someone to be presumed dead when missing for only a month, this perhaps could be called "not fair" to the person concerned, simply because a kidnapping or extended vacation involving an unexpected loss in communications, or an earthquake or tidal wave causing a temporary loss in contact or hospital stay while unconscious, might otherwise result in an unfair dispersal of property. On the other hand, to keep a missing person's property intact after 7 years have passed, perhaps even preventing a spouse from re-marrying or heirs from claiming assets which they could otherwise use for their own purposes, or even preventing an insurance company from paying a life-insurance policy (no evidence of death, they could claim), could equally be called "unfair" to the spouse or heirs, when death of the individual concerned is a much more likely presumption. Presumption is more likely conceived of as
- a socially acceptable, practically effective, in-order-to-go-on, wisdom-of-Solomon judgment in the face of missing evidence, which pro tem resolves competing claims that a certain default action is "fair" or not, or
- an allocator of time or resources, in the absence of clear evidence, or
- a stepping stone to other actions, themselves unconceived, and unconceivable at present, or
- in law, as part of a technique for continuing an argument or resolving a dispute when presenting a case.
One could always sit and do nothing and wait for the clear story to emerge. But when this is not possible, there is always presumption.]
p.15 Presumption - and the idea of burden of proof that is indissoluably connected to it - also serves as a fundamentally dialectical conception and has figured as such from classical antiquity to Hegel and beyond.
[JLJ - Presumption is a kind of rule for deciding who has won a contested argument - a presumption might be necessary because arguments can go on forever without a decision being made.]
p.21 Clearly there must be some class of claims that are allowed at least pro tem to enter uncontested into the framework of argumentation, because if everything were contested, the process of inquiry could not progress at all.
p.21 A presumption... is rendered reasonable by conforming to a well-established practice (or general rule) of taking something to be so. It is not a matter of evidence or substantiation but of authorization through an established probative practice.
p.23 Putting a proposition forward as "possible" or "probable" commits one to claiming no more than that it is "possibly true" or "probably true." Similarly, to assert P as a presumption is to say no more than that P is potentially or presumptively true, that it is a promising truth-candidate - but does not say that P is actually true, that it is a truth.
p.24 The mechanism of presumption accomplishes a crucial epistemological task in the structure of rational argumentation. There must clearly be some class of claims that are allowed to be at least provisionally accepted within the framework of argumentation, because if everything were contested, the process of inquiry could not progress at all.
p.25 Presumptively justified beliefs are quite sufficient to provide the raw materials for processes of rational deliberation... The reality is that we cannot pursue the cognitive project - the quest for information about the world - without undertaking certain initial presumptions.
p.26 there are always various alternatives: given that we are where we are, there is always a plurality of different directions in which to move. And to move on we have to do so in one or another of these directions: we cannot get on our horse and ride off in all of them at once. And until a particular direction is decided on as superior to the rest... there is neither point nor motivation for moving on.
[JLJ - Unless of course, we are constructing a diagnostic test of adaptive capacity. In this case, perhaps we create improvised 'surprise' scenarios to 'measure' the ability to adapt to the unforeseen.]
p.29 The move from plausibility to rationally warranted acceptance ("justified belief") is automatic in those cases where nihil obstat - that is, whenever there are no case-specific counterindications.
p.33 Cognitive presumption is... part of ongoing information development - of learning - and is not a matter of dogmatic closure.
p.33 Any acceptable specific presumption must be based on an appropriate generic presumption as an instance thereof.
p.34 Plausible truth-candidacy does not require or presuppose truth
p.37 Evidence does not ensure truth; it does no more than provide a presumptive induction of it. Its function is not that of a guarantee but that of a presumption.
p.41 In general, the more plausible a thesis, the more smoothly it is consistent and consonant with the rest of our knowledge of the matters at issue.
p.46 The step from a sensory experience ("I take myself to be seeing a cat") to an objective factual claim ("There is a cat over there and I am looking at it") is procedurally direct but epistemically mediated. And it is mediated not by an inference but by a policy - namely, the policy of trusting one's own senses, by a policy of presumption. And this policy itself... emerges in the school of praxis from the consideration that a long course of experience has taught us that our senses generally guide us aright - that the indications of visual experience... generally provide reliable information that can be implemented in practice.
p.46-47 [footnote] But why does knowledge root in presumptions rather than probabilities...? ...Probabilities, unlike presumptions, cannot be adequately grounded in policies; they must be grounded in purported facts.
p.47 Just what sorts of claims are presumptively justified?
p.47 epistemic presumption favors the ordinary, the usual, and the natural - its tendency is one of convenience and ease of operation in cognitive affairs. And the crux here is that presumption is a matter of cognitive economy - of the eminently rational policy of following "the path of least resistance" to an acceptable conclusion.
p.48 Presumption, in sum, is an ultimately pragmatic resource. It is a thought instrumentality that makes it possible for us to do the best we can in circumstances when something must be done... A cognitive presumption as such is not a thesis or theory: it represents a practical policy - a modus operandi.
p.50 arguments must have premises... Here is where presumptions come in. They furnish a starting point. Rational deliberation needs input materials, and principles of presumption provide them.
p.51 the rationale of our principles of presumption is uniformly one and the same: their functional utility in the context at issue. Our policies of presumption are justified through their purposive efficacy in facilitating realization of the inherent purposes and objectives of the domain in which they are instituted... these principles of presumption find their justification, insofar as they indeed are justified, through the common consideration that their operation is pragmatically effective.
p.52 the rationale of presumption is ultimately pragmatic... The machinery of presumption is part and parcel of the mechanisms of cognitive rationality because abandoning it would abort the entire project of rational inquiry at the very outset... There yet remains a question... What sorts of considerations validate our presumptions? How do they become entitled to their favorable epistemic status? ...ultimately... the validity of a presumption emerges ex post facto through the utility (both cognitive and practical) of the results it yields.
p.53 At bottom the rationale for presumption lies in their being critical for the enterprise at hand - in their being somewhere between absolutely necessary and eminently useful.
p.53 Still, at bottom, the validation of our presumptions is not really theoretical but practical... it argues only that when we indeed need or want here-and-now to resolve issues and fill information gaps, then those presumptions represent the most promising ways of doing so, affording us those means to accomplish our goals which - as best we can tell - offer the best prospect of success... And in the end all our presumptions are based on one fundamentally identical rationale of justification, namely, functional efficacy in the particular context of operation in which the presumption figures.
p.59 There is every reason to think that the cognitive methods and procedures at issue in the presumptions through which we standardly develop our view of reality evolve selectively by historic, evolutionary process of trial and error... An inquiry procedure is an instrument for organizing our experience into a systematized view of reality. And with any tool or method or instrument, the paramount question is, Does it work? Does it produce the desired result? Is it successful in practice in relation to the acquisition and development of information?
p.62 The point here is that all our cognitive methods and procedures - the instrumentality of presumption prominently included - are the products of developmental emergence through cultural selection that reflects a track record of success. Their validation inheres in their operation - they develop as they do because they substantially succeed in their intended role.
[JLJ - I would say that they are tricks that work.]
p.64-65 Without some recourse to presumption we simply could not manage to obtain the informative inputs indispensable for answering our questions about factual issues... An inquiry procedure... must afford an originative mechanism, capable of yielding an output of (putative) truths. Clearly if we hewed to the line that rationally discursive procedures can only extract truths from truths, we would be offered the unattractive choice between (1) accepting a "starter set" of nondiscursively self-evident or self-validating truths, or (2) a skepticism that admits defeat and gives up the whole project of a rational validation of truth-acceptance. This dilemma can be addressed effectively by resorting to presumptions. And so presumption represents a crucial epistemological resource that one would have to make room for in any case, even if it did not afford so convenient a filler for informational gaps.
[JLJ - Perhaps we can originate only truth candidates. It is up to the results which emerge from further detailed investigations, that resolve the end status of a truth candidate: a 'true' truth, a truth candidate 'still in the running,' or an unlikely candidate, for whatever reason.]
p.65-66 we proceed via truth estimates initially provided by principles of presumption that are ultimately reevaluated... retrospectively revalidated (ex post facto) by the results of that inquiry. But at this latter stage their epistemic status - though not their content - changes. In the first instance these presumptions have a merely provisional and regulative standing. But in the sequel they can attain a suitable degree of factual/constitutive substantiation through a course of cognitive development moving from the very tentative to the very secure... Presumption thus figures in rational inquiry as a key element in a dynamic process of knowledge acquisition.
[JLJ - This all works because an unknown truth stumbled on by an ignorant, but otherwise intelligent person, likely appears (at the level of emerging discovery glance) - to be a possible truth, or at minimum a curiosity deemed to be worthy of our attention. Only in later stages of investigation do we consider developed evidence that our possible truth is in fact the actual truth, the 'true' truth. Rescher has apparently never heard the term 'fact finding,' which is applied to investigations that are not yet complete, that are still separating facts from fictions, and are still making presumptions based on the early evidence at hand.]
p.67-68 What we must do in rational inquiry is pull ourselves up by our own bootstraps, relying on our principles of presumption but critically reappraising them as well. We begin by provisionally accepting certain theses whose initial status is not that of certified truths at all, but merely that of plausible postulations, whose role in inquiry is (at this stage) one of regulative facilitation... The logical structure of this justificatory process incorporates a feedback loop leading from the truths validated by the inquiry procedure back to the initial "merely presumptive" truths, so that the appropriateness of these initial, tentative, merely plausible presumptions can be reassessed.
p.68 matters need not always go smoothly... the outputs can bite the input-providing hand that feeds them, in due course rejecting some inputs as false. An initial presumption may well drop by the wayside in the long run.
p.69 A presumption-based, coherentist theory of knowledge stands in sharp contrast with the more restrictive foundationalist approach of the mainstream tradition of Western epistemology. For coherentism, unlike foundationalism, dispenses with any appeal to basic, immediately apprehensible truths of fact. It abandons the view that knowledge of the actual - or indeed even of the probable - requires a foundation of certainty. Instead, it takes the stance that truth is accessible in the extralogical realm on the basis of considerations of systemic best-fit among mere truth-presumptions, and thereby without any foundation of certainty.
[JLJ - Doesn't knowledge really involve two things,
- a knowledge claim, which can be either a guess or a revision of previous knowledge, and
- a diagnostic test of some kind (perhaps the winner of an argument between two people who have a vested interest, or closed-door debate among stakeholders at an academic Journal) which indicates that the knowledge claim is probably correct?
This process allows knowledge claims to bootstrap themselves onto whatever people think seem to work at the time, with room for debate and revision when new information arrives. Does true knowledge exist, or alternatively do we have only knowledge claims which we accept pro tem because we have to believe in something in order to "go on." Perhaps knowledge is just reification of belief - it is no more and no less than what we believe in, in order to "go on." ]
p.69 the difficulty with any sort of foundationalism lies in the matter of foundations.
p.70 Coherentism... proposes to cycle round and round the same given family of prospects and possibilities, sorting out, refitting, refining until a more sophisticatedly developed and more deeply elaborated resolution is ultimately arrived at. The information-extracting process developed along these lines is... one of a cyclic reappraisal and revision of the old, tightening our net around our ultimate conclusion as we move round and round again... However there must be a starting point.
p.70 The concept of a datum, whose role is pivotal in coherentist methodology, is something of a technical innovation... A datum is a truth-candidate, a proposition to be taken not as true, but as potentially or presumptively true. It is a prima facie truth in exactly the same sense in which one speaks of prima facie duties in ethics - a thesis that we would in the circumstances, be prepared to class as true provided that no countervailing considerations are operative.
p.74-75 A reliance upon data as merely presumptive truths makes it possible to contemplate a coherence theory that produces its truth claims not ex nihilo (which would be impossible) but yet from a basis that does not itself demand any prior determinations of truthfulness as such. A coherence criterion can, on this basis, furnish a mechanism that is originative of truth - that is, it yields truths - via presumptions that yield (putatively) true outputs without requiring that truths must also be present among the supplied inputs.
p.79 Default reasoning plays a significant role in the theory of reasoning and also in artificial intelligence.
p.80 if such a policy or typicality presumption may lead us down the primrose path of error, how is it ever to be justified? The answer here lies precisely in the consideration that what is at issue is not a truth-claim but a policy or procedure. And such policies of procedure are not justified in the theoretical (i.e., factual) order but in the practical, or pragmatic order of deliberation.
[JLJ - Exactly. This is just what investigation looks like when we attempt to deconstruct it into parts. The irony here is that a truth does not necessarily result from the assemblage of other truths - it is perhaps stumbled upon, or uncovered, in the pursuit of something else.]
p.81 Induction rests on presumption-geared default reasoning and its conclusions are thus always at risk to further or better data since what looks to be typical or representative may in due course turn out not to be so.
p.83 To obtain a conclusion we must now suppose that nothing untoward is hidden from our sight - that nothing unmentioned intervenes. And this always brings the factor of presumption upon the scene.
p.84 With default reasoning in general and induction in particular we run the risk that our conclusions may go awry thanks to our reliance on (generally tacit) suppositions of normality or typicality that may fail in the circumstances at hand.
p.86 no highly secure statement about objective reality can say exactly and in complete detail how matters stand. To capture the truth of things by means of language we must proceed by way of "warranted approximation," In general we can be sure of how things "usually" are and how they "roughly" are, but not how they always and exactly are.
p.87 In many situations default reasoning affords the best available pathway to our ultimate very practical requirement for information - for answering in a cogent and circumstantially responsible way a question that we need to resolve.
p.92 Trust is, of course, something that we can have not only in people but in cognitive sources at large.
p.93 Our standard cognitive practices incorporate a host of fundamental presumptions of initial credibility, in the absence of concrete evidence to the contrary... Our cognitive presumptions are, throughout, presumptions of trustworthiness.
p.98 while common sense is a sound and reliable guide, this is so only in the realm of everyday issues. Common sense does not resolve conundrums - it does no more (but also no less!) than to afford straightforward answers to commonplace issues.
p.102 Science, after all, is not designed to tell us where to go; it is designed to tell us how to get there efficiently once we have made up our minds about this essential preliminary.
p.112 A significant feature of normal communication is that it follows a policy of not saying what does not really need to be said. That presumption of normalcy - that the relevant circumstances and conditions stand in their prosaically normal and natural condition unless otherwise indicated - is a crucial factor in communicative economy - an important communicative ground rule that authorizes all sorts of inferences ex silentio.
p.113 Again, when we are discussing someone - say, someone I know whom you are about to meet at a party - we operate with the tacit convention that I will tell you the relevantly pertinent facts, and that in those respects that I pass over, the situation is ordinary and normal... There is an operational presumption of normalcy in unmentioned respects that is an essential part of the rational economy of the process.
p.114 There is also the closely related presumption that what is left unsaid does not abrogate or otherwise crucially alter what is naturally inferred from what is actually said.
p.115-116 Communication thus proceeds on ground rules of communicative efficiency. And those presumptions governing silence and normalcy play a pivotal role here through underwriting such principles as "what is left out is unimportant for the issue at hand," "what is left out will not significantly alter the indications plausibly drawn from what is put in," and "what is left out would not call for a substantial revision of what has been said." Effective communication would become impracticable without presumptions that enable us to fill in the gaps between what is explicitly said.
The standard presumptions that underlie our communicative practices are emphatically not validatable as established facts... But their justification becomes straightforward on economic grounds, as practices that represent the most efficient and economical way to accomplish our communicative work.
p.119 All procedures for acquiring information... involve expenditures of some sort... And whether this outlay is warranted depends on the correlative advantages - preeminently including the cognitive benefits of acquired information.
p.126 Induction proceeds by way of constructing the most economical structures to house the available data comfortably... Induction is thus a process of implementing the general idea of cognitive economy by building up the simplest structure capable of resolving our cognitive problems.
p.128 economy and its other system-definitive cogeners - simplicity, uniformity, and the rest - are natural guidelines. To be sure, whether the direction in which they point us is actually correct is something that remains to be seen. But they clearly afford the most natural and promising starting point.
p.130 We need answers to our questions about the world and the process of getting there is governed by an analogue of Occam's razor - a principle of parsimony to the effect that needless complexity is to be avoided.
p.131 The crucial fact is that simplicity preference is a cognitive policy recommended by considerations of cost effectiveness; in the setting of the cognitive purposes at issue, it affords a maximally advantageous inquiry mechanism.
[JLJ - That is, unless we are attempting to resolve situations where appearances are deceiving. Say a woman hires a hit-man to murder her husband and tells the hit man to 'make it look like an accident' (I watch too much TV). The hit-man confronts the victim as he walks through a high-crime area and makes the murder look like a robbery gone wrong. An investigator might look to the 'simple solution' in this case, a random killing, but we know this is not correct because the hit man was being strategic and clever in hiding his tracks. 'Simplicity preference' does not work all the time in a complicated world where misdirection is possible and things are sometimes not what they seem to be.]
p.142 such methodological processes... will generally lead us aright. Though not infallible, they are good guides to practice in affording us general adequacy rather than failproof correctness. And the justification at issue is thus one of functional efficacy - of serving the purposes of the practice at issue effectively. Here, as elsewhere, presumption is less a matter of demonstrating a universal truth than of validating a procedural practice on the basis of its general effectiveness.
[JLJ - Again, presumptions are simply tricks that work. But at some point we must justify our presumptions.]
p.150 Throughout all settings in which presumption plays a role - inquiry, communication, and social interaction preeminently included - the same fundamental factor is at work: rational economy. Presumption, as we have seen, is always something of a leap in the dark. It involves a risk that we are prepared to run for the promise of goal attainment.
[JLJ - Yes, but we have to "go on" somehow. If not presumption, then what competing 'mechanism' for 'going on' offers as much promise? If we made a list of all the things we could do, which might involve giving up completely, stopping for a while, using another approach, waiting for something magical to happen, flipping a coin, assigning someone else to work the problem, etc., we might find that making presumptions and following where they lead might - in the long run - be the best use of our time. Rescher rarely touches on the idea of wisdom because it encroaches too much on his prized (but flawed) concept of rationality. Rationality by itself does not win wars, create success in business, win sports championships, or win elected office - that is, win hotly contested events - without involving other concepts such as strategy, wisdom, experience, planning and hard work.]
p.152 Here the question before us is this: in regard to matters of practice, should a diminutive probability... be seen as being indistinguishable from zero and treated as having no magnitude at all?
[JLJ - This is like the question: Should you upgrade the quality of the lock on your front door? The probability is very small that someone will try to break in, but if they do try, a higher grade lock might frustrate them into abandoning their effort. I would argue that the answer involves determining a "healthy level" of paranoia, then acting accordingly. In playing a complex game of strategy, the accumulation of small advantages over time is one way to build an advantage in position. We cannot see the accumulation ahead of time, but know that if our opponent plays weakly, that it will in fact happen. <satire>The probability that Rescher will produce an adequately proof-read work is small enough to become - effectively indistinguishable from - zero.</satire>]
p.155 Of course, the question remains: How small is small enough for being "effectively zero"?
[JLJ - Rescher once more becomes ensnared in the I-don't-want-to-discuss-strategy trap. Strategically, your opponent will aim to place you in proven positions where your short-cut-style thinking - whatever that happens to be - will place you in trouble. Strategically, you must evaluate the situation using a technique which the opponent is not directly familiar with, and operate with sufficient misdirection and adaptive capacity to recover from any oversights. How small is small enough for being effectively zero? Too hard to really say without considering how hard someone is willing to work to take advantage of you lowering your guard. Professional criminals rely on the fact that some people leave their house or car doors unlocked because it is convenient to do so, and because there appears to be little or no risk. Practically, you should never let your guard down, and you ought to operate with tripwires of various sorts which trigger to steer you out of imagined danger when subtle cues suggest that things are not what they seem to be.]
p.162 To be sure, a further worry looms on the horizon. For the fact of it is that a substantial accumulation of minute chances can become significant.
p.163 Accordingly, we can now lay claim to the following principle of practical deliberation:
In a course of practical reasoning - but here only - it is acceptable to include among the premises one - but only one! - proposition that is no more than virtually certain.
p.166 Most philosophical theorists of knowledge... have been concerned primarily with knowledge in the sense of what we know for certain. In consequence it has transpired that... contemporary epistemology has almost wholly neglected the range of conceptions in the region of uncertainty, the gray area of concepts that, like presumption and plausibility, have an indecisively tentative impetus toward truth.
p.167 presumption... alone among rational processes enables us to resolve issues whose evidentiation has not reached the end of an ultimately incompletable journey.
p.168 The fact of it is that we can and do operate effectively with presumptions in many areas of rational endeavor... Presumption is a versatile cognitive instrumentality that serves us well in a broad spectrum of epistemic applications.
p.168-169 One of the principal services afforded to us by a recourse to presumption lies in its affording the basis for a dynamic theory of knowledge - one that does not simply begin with putative truths obtained ex nihilo, but rather sees the knowledge acquisition as a process moving from tentative presumption to ultimate acceptance. The concepts of plausibility and presumption provide the means for a characteristically variant, nonfoundationalist approach to probative reasoning that sees knowledge development as a continuous upgrading of fallible materials rather than as a two-phase process of extracting inferential knowledge from immediate and supposedly self-evident knowledge of some sort.
|
