Two kinds of reasoning

According to one view of reasoning, people can evaluate arguments in at least two qualitatively different ways: in terms of their deductive correctness and in terms of their inductive strength. According to a second view, assessments of both correctness and strength are a function of an argument's position on a single psychological continuum (e.g., subjective conditional probability). A deductively correct argument is one with the maximum value on this continuum; a strong argument is one with a high value. The present experiment tested these theories by asking participants to evaluate the same set of arguments for correctness and strength. The results produced an interaction between type of argument and instructions: In some conditions, participants judged one argument deductively correct more often than a second, but judged the second argument inductively strong more often than the first. This finding supports the view that people have distinct ways to evaluate arguments.     

《物种起源》中的类比方法及其论证作用

达尔文在《物种起源》中区分了自然选择学说包括的两种不同的原理：适应原理和性状分歧原理。他对类比方法的应用也有两种：一是类比论证,二是发现的启发法。关于适应原理的类比只起到了启发法的作用,达尔文对这种类比的理解是假说一演绎主义的;关于性状分歧原理的类比是一种归纳推理,达尔文对这种类比的理解是归纳主义的。     

Is Induction Epistemologically Prior to Deduction?

Most philosophers hold that the use of our deductive powers confers an especially strong warrant on some of our mathematical and logical beliefs. By contrast, many of the same philosophers hold that it is a matter of serious debate whether any inductive inferences are cogent. That is, they hold that we might well have no warrant for inductively licensed beliefs, such as generalizations. I argue that we cannot know that we know logical and mathematical truths unless we use induction. Our confidence in our logical and mathematical powers is not justified if we are inductive sceptics. This means that inductive scepticism leads to a deductive scepticism. I conclude that we should either be philosophical sceptics about our knowledge of deduction and induction, or accept that some of our inductive inferences are cogent.     

The Possibility of Inductive Moral Argumets

Abstract

Is it possible to have moral knowledge? ‘Moral justification skeptics’ hold it is not, because moral beliefs cannot have the sort of epistemic justification necessary for knowledge. This skeptical stance can be summed up in a single, eat argument, which includes the premise that ‘Inductive arguments from non-moral premises to moral conclusions are not possible.’ Other premises in the argument may rejected, but only at some cost. It would be noteworthy, therefore, if ‘inductive inferentialism’ about morals were show to be at least possible. Some philosophers may suppose that inductive moral argumets from non-moral premises cannot get off the ground, but I show that a perfectly legitimate inductive moral argument exists. This argument has on-moral premises and a moral conclusion, its premises are related to its conclusion in the right way, and it avoids some of the problems of other, better-know argumets from ‘Is’ to ‘Ought’.     

From observability to manipulability: Extending the inductive arguments for realism

In recent years there have been several attempts to construct inductive arguments for some version of scientific realism. Neither the characteristics of what would count as inductive evidence nor the conclusion to be inferred have been specified in ways that escape sceptical criticism. By introducing the pragmatic criterion of manipulative efficacy for a good theory and by sharpening the specification of the necessary inductive principle, the viability of a mutually supporting pair of argument forms are defended. It is shown that by the use of these forms, taken together, a sequence of inductive arguments could be constructed, given suitable cases histories to serve as evidence. It also shown that the best inductive argument for the most daring realist claim is the weakest when compared with similarly structured arguments for less daring claims.A popular version of this argument appeared in Perspectives on Science, 1994.     

Show Me the Argument: Empirically Testing the Armchair Philosophy Picture

Many philosophers subscribe to the view that philosophy is a priori and in the business of discovering necessary truths from the armchair. This paper sets out to empirically test this picture. If this were the case, we would expect to see this reflected in philosophical practice. In particular, we would expect philosophers to advance mostly deductive, rather than inductive, arguments. The paper shows that the percentage of philosophy articles advancing deductive arguments is higher than those advancing inductive arguments, which is what we would expect from the vantage point of the armchair philosophy picture. The results also show, however, that the percentages of articles advancing deductive arguments and those advancing inductive arguments are converging over time and that the difference between inductive and deductive ratios is declining over time. This trend suggests that deductive arguments are gradually losing their status as the dominant form of argumentation in philosophy.     

Relativism, Absolutism, and Tolerance

Abstract: A common view is that relativism requires tolerance. We argue that there is no deductive relation between relativism and tolerance, but also that relativism is not incompatible with tolerance. Next we note that there is no standard inductive relation between relativism and tolerance—no inductive enumeration, argument to the best explanation, or causal argument links the two. Two inductive arguments of a different sort that link them are then exposed and criticized at length. The first considers relativism from the objective point of view ‘of the universe’, the second from the subjective point of view of the relativist herself. Both arguments fail. There is similarly no deductive relation between absolutism and tolerance—neither entails the other—and no inductive connection of any sort links the two. We conclude that tolerance, whether unlimited or restricted, is independent of both relativism and absolutism. A metaethical theory that says only that there is one true or valid ethical code, or that there is a plurality of equally true or valid ethical codes, tells us nothing about whether we should be tolerant, much less how tolerant we should be.     

Monotonicity in Practical Reasoning

Classic deductive logic entails that once a conclusion is sustained by a valid argument, the argument can never be invalidated, no matter how many new premises are added. This derived property of deductive reasoning is known as monotonicity. Monotonicity is thought to conflict with the defeasibility of reasoning in natural language, where the discovery of new information often leads us to reject conclusions that we once accepted. This perceived failure of monotonic reasoning to observe the defeasibility of natural-language arguments has led some philosophers to abandon deduction itself (!), often in favor of new, non-monotonic systems of inference known as `default logics'. But these radical logics (e.g., Ray Reiter's default logic) introduce their desired defeasibility at the expense of other, equally important intuitions about natural-language reasoning. And, as a matter of fact, if we recognize that monotonicity is a property of the form of a deductive argument and not its content (i.e., the claims in the premise(s) and conclusion), we can see how the common-sense notion of defeasibility can actually be captured by a purely deductive system.     

Logical Knowledge

It seems obvious that our beliefs are logically imperfect in two ways: they are neither deductively closed nor logically consistent. But this common-sense truism has been judged erroneous by some philosophers in the light of various arguments. In defence of common sense I consider and rebut interpretative arguments for logical perfection and show that the assumption espoused by common sense is theoretically superior, and capable - unlike its rival - of accounting for the informativeness of mathematics. Finally, I suggest that common sense opens the way to genuine disputes about the correct logic.     

The logic of the medical research article

As do all forms of science, medical theories have a factual as well as a logical basis. New information is presented in medical research articles. These papers have three separate arguments: the argument of the hypothesis, the argument of the experimental protocol, and the argument of the hypothesis's judgment. These arguments may be examples of the hypothetico-deductive or confirmational model of scientific inference. The logical form of these arguments are informal and inductive rather than formal and deductive. Understanding the nature of the logic of the medical research article may help avoid erroneous conclusions.     

The Organization of Justificatory Discourse in Interaction: A Comparison Within and Across Cultures

Previous scholarship has focused on inductive and deductive patterns as the two predominant modes of reasoning. In this paper, we argue that there are many ways that people from diverse cultures organize their justificatory reasoning in conversation with others and that these patterns are connected, in part, to cultural beliefs and values. We report on a study of people who identify themselves as being in one of four cultural groups: African Americans, Asian Americans, Asians, and European Americans. The types of organization they used in their conversations included deductive, inductive, abductive, and narrative patterns. Abduction occurred as often as induction and deduction across groups. Narratives were used equally by all of the groups, but they occurred less frequently than the other types. Asian Americans used inductive patterns more than other types, and Asians were most likely to reason deductively. These choices did not appear to have an effect on partners' judgments, although Asians received the lowest appropriateness ratings, and both Asians and Asian Americans were given the lowest effectiveness ratings.     

Some Artificial Intelligence Tools for Argument Evaluation: An Introduction

Even though tools for identifying and analyzing arguments are now in wide use in the field of argumentation studies, so far there is a paucity of resources for evaluating real arguments, aside from using deductive logic or Bayesian rules that apply to inductive arguments. In this paper it is shown that recent developments in artificial intelligence in the area of computational systems for modeling defeasible argumentation reveal a different approach that is currently making interesting progress. It is shown how these systems provide the general outlines for a system of argument evaluation that can be applied to legal arguments as well as everyday conversational arguments to assist a user to evaluate an argument.     

Induction,Normality and Reasoning with Arbitrary Objects

This paper concerns the apparent fact — discussed by Sinan Dogramaci (2010) and Brian Weatherson (2012) — that inductive reasoning often interacts in disastrous ways with patterns of reasoning that seem perfectly fine in the deductive case. In contrast to Dogramaci's and Weatherson's own suggestions, I argue that these cases show that we cannot reason inductively about arbitrary objects. Moreover, as I argue, this prohibition is neatly explained by a certain hypothesis about the rational basis of inductive reasoning — namely, the hypothesis that inductive reasoning is fundamentally reasoning about what normally happens (in a non‐statistical sense).     

The macrostructure of informal arguments: A proposed model and analysis

Theories of informal reasoning and critical thinking often maintain that everyday, informal arguments can be classified into types based on the specific organization that the premises or reasons enter into in their support for the conclusion (Snoeck Henkemans, 2000; Vorobej, 1995b). Three general types are identified: convergent, coordinately linked, and subordinately linked arguments. There has been no empirical research, however, to determine whether these structural distinctions have any psychological reality. In the first two of four experiments, college students were presented with premise pairs from larger, informal arguments and were asked to judge the nature of the relationship between the premises in a pair. The judgments involved applying “tests” of linkage, subordination, and so on, that have been proposed in the theoretical literature on argument analysis (e.g., Walton, 1996a; Yanal, 1991). Results suggest that adults can effectively distinguish between linked (interdependent) and convergent relationships and can further distinguish between interdependencies that are full and those that are merely partial. Adults also distinguished between subordinate and nonsubordinate relations. Experiments 3 and 4 provide evidence that adults make use of information about argument structure in evaluating argument strength and in categorizing arguments. Experiment 4 further suggests that facility with macrostructure is only modestly related to deductive reasoning competence. Findings are framed in terms of a speculative account of how argument structure is identified and mentally represented.     

Who Needs Valid Moral Arguments? (Dedicated to the Memory of R.M. Chisholm, 1916–1999)

Why have so many philosophers agonised over the possibility of valid arguments from factual premises to moral conclusions? I suggest that they have done so, because of worries over a sceptical argument that has as one of its premises, `All moral knowledge must be non-inferential, or, if inferential, based on valid arguments or strong inductive arguments from factual premises'. I argue that this premise is false.     

Development of logical reasoning: children's ability to verbally explain the nature of the distinction between logical and nonlogical forms of argument

Previous research by D. Moshman and B. Franks (1986) supported the hypothesis that children do not explicitly understand the nature of the distinction between logical and nonlogical forms of argument. This research examined the performance of 8-11-year-olds (N = 220) on Moshman and Franks's experimental tasks when the children were cued to apply particular comprehension strategies. Findings from 2 experiments indicated that a significant number of children are capable of explicitly recognizing the necessity of logical forms and the indeterminacy of nonlogical forms and that this competence must be distinguished from their tendency to fail to attend to structural relationships between propositions and to monitor the intrusion of extraneous personal knowledge in assessing the validity of an argument. The findings suggest that all of these competencies are important components of the ability to distinguish logical and nonlogical arguments.     

The epistemic significance of valid inference

The traditional picture of logic takes it for granted that ??valid arguments have a fundamental epistemic significance??, but neither model theory nor traditional proof theory dealing with formal system has been able to give an account of this significance. Since valid arguments as usually understood do not in general have any epistemic significance, the problem is to explain how and why we can nevertheless use them sometimes to acquire knowledge. It is suggested that we should distinguish between arguments and acts of inferences and that we have to reconsider the latter notion to arrive at the desired explanation. More precisely, the notions should be developed so that the following relationship holds: one gets in possession of a ground for a conclusion by inferring it from premisses for which one already has grounds, provided that the inference in question is valid. The paper proposes explications of the concepts of ground and deductively valid inference so that this relationship holds as a conceptual truth. Logical validity of inference is seen as a special case of deductive validity, but does not add anything as far as epistemic significance is concerned??it resides already in the deductively valid inferences.     

Loar's Defence of Physicalism

Brian Loar believes he has refuted all those antiphysicalist arguments that take as their point of departure observations about what is or isn’t conceivable. I argue that there remains an important, popular and plausible‐looking form of conceivability argument that Loar has entirely overlooked. Though he may not have realized it, Saul Kripke presents, or comes close to presenting, two fundamentally different forms of conceivability argument. I distinguish the two arguments and point out that while Loar has succeeded in refuting one of Kripke's arguments he has not refuted the other. Loar is mistaken: physicalism still faces an apparently insurmountable conceptual obstacle.     

Mathematics,Morality, and Self‐Effacement

I argue that certain species of belief, such as mathematical, logical, and normative beliefs, are insulated from a form of Harman‐style debunking argument whereas moral beliefs, the primary target of such arguments, are not. Harman‐style arguments have been misunderstood as attempts to directly undermine our moral beliefs. They are rather best given as burden‐shifting arguments, concluding that we need additional reasons to maintain our moral beliefs. If we understand them this way, then we can see why moral beliefs are vulnerable to such arguments while mathematical, logical, and normative beliefs are not—the very construction of Harman‐style skeptical arguments requires the truth of significant fragments of our mathematical, logical, and normative beliefs, but requires no such thing of our moral beliefs. Given this property, Harman‐style skeptical arguments against logical, mathematical, and normative beliefs are self‐effacing; doubting these beliefs on the basis of such arguments results in the loss of our reasons for doubt. But we can cleanly doubt the truth of morality.