1. Field of the Invention
This invention is directed to systems and methods for visualizing argument and its constituent elements and related data.
2. Related Art
An argument ties facts and evidence, which either support or refute a hypothesis, to that hypothesis in a logical sequence. In text books, arguments are often simple and easily followed. However, in the real world, arguments may be stunningly complex. Multiple hypotheses may be proposed to deal with the available facts. These hypotheses may be competing, contradictory or even mutually exclusive. The facts useable to support or refute these hypotheses are often contradictory, sometimes spoofed, and, all too frequently, missing. Reasons for linking specific facts to particular hypotheses as either supporting or refuting evidence can arbitrary, biased, and/or based on assumptions, which may themselves be less than fully appreciated. Creating robust, well-reasoned arguments that appropriately used the facts as evidence to support or refute the hypotheses in the presence of uncertain information is extremely difficult.
At its most basic level, an argument comprises hypotheses and zero, one or more sub-hypotheses, a plurality of facts, which become evidence when linked to hypotheses, sub-hypotheses or other facts, and inferences. These argument elements can be arranged in proof forms that capture the relationships among the evidence and the various hypotheses and sub-hypotheses. It is believed that conclusions derived from argument-based analyses of the available facts are more rigorous, robust and less sensitive to any biases of the person doing the analysis than results that are derived from more ad-hoc approaches.
Information visualization has long been recognized as a technique that allows deeper understanding of complex masses of information. It has been long recognized that information visualization can be used to understand structured arguments. Information visualization was first applied to structured arguments by Wigmore, who created techniques for visualizing evidence in legal proceedings. Wigmore, a famous evidence scholar, developed a graphical method for charting legal evidence that used an elaborate syntax and a set of symbols to represent statements, propositions, evidence, and inferential links.
Stephen Toulmin, in his book “The Uses of Argument” (Cambridge University Press, 1958) describes another method for visualizing an argument. However, both the Wigmore and Toulmin argument forms can become incredibly complex and unwieldy when having to deal with the mass of facts, evidence and available hypotheses that occur in real world situations. Thus, while Wigmore and Toulmin have pioneered the idea of using charts to visualize arguments, these techniques are typically impractical and are not widely used. There are many reasons why analysts have been reluctant to use Wigmore and Toulmin argument visualization. First, constructing Wigmorean or Toulminian evidence charts is exceedingly difficult and a significant chore, even when using conventional graph-drawing software packages. Second, as outlined above, the charts can be expansive and stunningly complex. One apocryphal story tells of a Wigmorean evidence chart that measured 37 feet in length.
Third, and most importantly, to construct Wigmorean or Toulminian evidence charts, the relationships between the evidence and the hypotheses must be known a priori. Thus, when using these techniques, the process of discovery is lost. That is, in most real-world situations, new facts are continually being found to fill in the holes in the current evidence, resulting in new insights being revealed, which in turn leads to recognizing that other evidence may be missing. Thus, Wigmorean or Toulminian evidence charts are typically applicable only after the evidence is understood.
Hypotheses are questions or conjectures of interest to an observer. Hypotheses may involve alternative possible explanations of facts, such as events or occurrences, possible answers, alternative estimates, or prediction of future events. Hypotheses may be contradictory or even mutually exclusive.
Hypotheses may also have substructure. That is, a high-level hypothesis may be partitionable into a set of sub-hypotheses that forms a hierarchical tree. The tree may in fact be several levels deep before the sub-hypothesis become questions that can be directly assessed and answered via available fact. A given cascading decomposition sequence of hypotheses and sub-hypotheses is not necessarily unique, and multiple sub-hypotheses may be simultaneously satisfied.
Facts become evidence when a fact becomes relevant to establishing or disproving a hypothesis or sub-hypothesis. Inferences are logical links that connect a fact to a hypothesis as evidence. Facts can also either support or refute an inference linking another fact to a hypothesis. Thus, facts can be linked by inferences to inferences as well as to hypotheses. Because the meaning or inference of a fact relative to a hypothesis can change as new facts are discovered and linked into the argument, analyzing a set of facts and organizing them into an argument that supports or disproves a given hypothesis is an interactive process. Thus, the static nature of the classical Wigmore and Toulmin approaches is ill-suited to situations, such as intelligence analysis, criminal investigations, and/or legal analysis of facts to determine potential causation and liability, because these techniques assume that the set of facts is complete and fixed and these techniques generate charts or visualizations that are not easily modifiable in view of new facts and/or new hypotheses or sub-hypotheses.
This invention provides systems and methods for visualizing hypotheses, facts and inferential networks linking the facts to the hypotheses.
This invention separately provides systems and methods for visualizing hypotheses, sub-hypotheses and conjectures.
This invention separately provides systems and methods for visualizing sets of facts and evidence.
This invention separately provides systems and methods for organizing interrelationships between facts within a set of facts.
This invention separately provides systems and methods for recording, organizing and or visualizing assumptions associated with hypotheses.
This invention separately provides systems and methods for assigning and visualizing values for evidentiary and inferential parameters.
This invention separately provides systems and methods for extracting information from documents into a collection of potentially relevant facts.
This invention separately provides systems and methods for visualizing an inference network of a hypothesis and facts relevant to that hypothesis.
This invention separately provides systems and methods for visualizing hypothesis and facts relevant to that hypothesis in a tabular form.
This invention separately provides systems and methods for visualizing facts in a timeline form.
This invention separately provides systems and methods for visualizing inter-relationships among facts, hypotheses, and conjectures.
This invention separately provides systems and methods for interactively creating, modifying, updating and altering Wigmorean and/or Toulminian argument forms.
This invention separately provides systems and methods for scoring a hypothesis and its sub-hypothesis based on the linked evidence using a Bayesian belief network.
In various exemplary embodiments of systems and methods according to this invention, an argument comprises hypotheses, sub-hypotheses and conjectures, facts, and inferences that link the facts as evidence to various ones of the hypotheses and sub-hypotheses. The hypotheses, sub-hypotheses, facts, evidence, inference and arguments are visualized using a plurality of interrelated graphical user interfaces or screens. In various exemplary embodiments, a main visualization screen includes a fact visualization portion, a hypothesis visualization portion and an argument construction visualization portion. In various exemplary embodiments, the hypothesis visualization portion includes a main hypothesis potion, a sub-hypothesis portion and a conjectures portion. In various exemplary embodiments, the evidence visualization portion comprises an evidence display portion, an evidence details portion and a variety of visualization selection widgets that allow different evidence visualization or marshaling techniques to be applied to visualize the facts. In various exemplary embodiments, the argument construction visualization potion allows hypotheses, sub-hypotheses and conjectures to be associated into an argument, various facts to be associated with the hypotheses and sub-hypotheses as evidence, and inference links to be added to link the facts to various ones of the hypotheses of the argument.
In various exemplary embodiments, a hypothesis properties graphical user interface or screen allows various properties about a particular hypothesis to be viewed and made explicit. In various exemplary embodiments, the hypothesis properties screen allows the hypothesis to be named, to be given a description, and various assumptions to be made explicit or associated with the hypothesis. In various exemplary embodiments, the hypothesis properties screen includes a portion that allows various facts that have been associated with the particular hypothesis to be viewed.
In various exemplary embodiments, an evidence properties graphical user interface or a screen allows a particular fact to be named and described and values for various parameters to be associated with each different fact. In various exemplary embodiments, the parameters include source parameters and applicability parameters. In various exemplary embodiments, an evidence graphical user interface or screen allows for evidence facts to rearranged, sorted, filtered, and marshaled according to the evidence parameters including the source and applicability parameters. In various exemplary embodiments, the evidence facts can be organized into an evidence grid or the like.
In various exemplary embodiments of systems and methods according to this invention, a tool bar or timeline can be incorporated into a word processing program or the like to allow a portion of a document being viewed with that word processing program to be copied and incorporated into an argument as a new fact.
In various exemplary embodiments, an argument visualization graphical user interface or screen allows the inferences of an argument to be viewed and the visualization parameters modified.
In various exemplary embodiments, a fact or evidence marshalling screen or set of screens allows a set of facts, some, none or all of which may have been associated with one or a variety of hypotheses as evidence, to be visualized relative to each other and/or to those one or more hypothesis in one or more of a tabular form, a timeline form, a link form or the like. In various exemplary embodiments of systems and methods according to this invention, the facts, evidence, inferential links and hypothesis of an argument can be visualized using either Wigmorean forms or Toulminian forms. In various exemplary embodiments, the visualization can be toggled between the Wigmorean form and the Toulminian form.
In various exemplary embodiments, one or more hypotheses of an argument can be scored by creating a Bayesian belief network out of each hypotheses and the various facts that are linked to each hypothesis as evidence using the inferential links. In various exemplary embodiments, each hypothesis can be analyzed independently, with each hypothesis being scored independently of the other hypotheses. In various other exemplary embodiments, the hypotheses can be scored together, where the sum of these scores for the hypotheses must total one. In various exemplary embodiments, the scoring can be toggled between these two scoring functions.
These and other features and advantages of various exemplary embodiments of systems and methods according to this invention are described, or are apparent from, the following detailed description of various exemplary embodiments of the systems and methods of according to this invention.
Various exemplary embodiments of the systems and methods of this invention will be described in detail, with reference to the following figures, wherein:
The essential aspects of an argument include at least three components, namely, evidence, hypothesis and inferences. Each of these components is philosophically deep and related to the fundamental aspects of science and logic. In fact, at a basic level, evidence has been described as being unable to be defined in such a way that its definition is not circular.
Evidence involves a fact and a hypothesis that is of interest to an observer. Facts come in an essentially unlimited variety and form. Facts depend upon the observers supplying the facts. Accordingly, facts often change through time. In general, the intelligence community, the scientific community and other groups who deal with facts on a daily basis have identified four fundamental aspects of facts. First, it is impossible to know all of the facts regarding a particular situation. Second, there is frequent disagreement about what the facts are regarding some situations of concern. Persons having different points of a view or approaching the problem from different avenues may see “the facts” quite differently. Third, facts are frequently not stationary. A source that was believable or credible in the past may now appear to be untruthful. Accordingly, the facts supplied by that source may have to be reevaluated as the credibility or other properties of that source change over time. Finally, what are defined as “facts” depends upon the extent to which those facts have corroborating evidence from other, preferably independent, sources.
A fact becomes evidence when that fact tends to make a hypothesis either more likely or less likely to be correct. That is, a fact becomes evidence when it is relevant, rather than irrelevant, to a particular hypothesis.
Although there are many species of evidence, for inferential purposes, there appear to be a relatively small number of distinct types. These types include tangible evidence, i.e., physical items that can be examined such as, for example, objects, documents, images, charts, measurements, direct recordings and the like. Evidence can also be testimonial, i.e., statements made by a person relating their direct perceptions, such as things heard, seen, felt, smelled or tasted. Testimonial evidence can also include opinion statements made by experts or laymen based on their interpretation of directly-experienced facts, such as those indicated above. Testimonial evidence can also encompass second-hand statements, such as gossip, hearsay and the like. Evidence can also be authoritative, i.e., generally accepted as true without requiring any evidence that the authoritative evidence is in fact true.
Evidence can also be weighted for its usefulness in proving or disproving a hypothesis. Various parameters for evidence include relevance, credibility and admissibility. Relevance describes how directly the fact influences or tends to prove or disprove the hypothesis. For example, evidence can be directly relevant, circumstantially relevant, or even of ancillary relevance. Credibility describes the weight or certainty the analyst has that the underlying fact is in fact true. Finally, admissibility goes to whether the evidence is even allowed to be used. For example, in the U.S. legal system, there are strict rules that determine whether evidence can be admitted. For example, in criminal proceedings, evidence obtained by illegal searches is inadmissible. In the U.S. legal system, judges determine the relevance and admissibility of facts into evidence, while juries are responsible for assessing the credibility of facts that have been entered into evidence. In scientific communities, evidence is only admissible to prove or disprove a hypothesis if it can be repeated independently by other researchers. Intelligence communities are also limited to evidence admissibility rules. For example, there are strict laws that prohibit U.S. intelligence agencies from gathering evidence on U.S. citizens; that is, such evidence is inadmissible.
Once a fact is determined to be relevant to a hypothesis, credible, in that that fact is at least likely to be accurate and true, and admissible, the effect that evidence can have on a hypothesis can be positive or supportive of a hypothesis, negative, i.e., contradicting or tending to disprove a hypothesis, or missing. For example, the fact that an expected event occurred is positive evidence, as is the fact that an unexpected event did not occur. In contrast, the fact that an expected event did not occur, or that an unexpected event did occur, is negative evidence. Missing evidence is evidence that is expected but for some other reason, other than the hypothesis being wrong, was not produced or even discoverable. In the U.S. legal system, when evidence is missing, it is presumed to be against the interest of the party who is most interested in relying on that evidence; otherwise, the missing evidence would have been produced. In contrast, in intelligence analysis, missing and negative evidence may be just as powerful in establishing inferences as positive or negative evidence. In any case, missing evidence should not be overlooked.
There may be recurrent combinations of evidence. This occurs when multiple individual facts in evidence are related to the same hypothesis. There are two possible types of relationships, dissonant and harmonious. Two pieces of harmonious evidence tend to both support or both disprove a particular hypothesis. In contrast, two pieces of dissonant evidence contain internal conflicts such as when each piece of evidence implies that the other is true, but each piece of evidence leads to different conclusions about the ultimate hypothesis. Dissonant combinations of evidence may be contradictory or conflicting. Contradictory evidence involves events that are mutual exclusive. Contradictions are usually settled on the basis of evidence credibility. Conflicting evidence involves two events that can both occur jointly but seem to favor different hypothesis. Similarly, harmonious evidence can be either corroborative or convergent. Corroborative evidence involves concurrent evidence about the same event, or ancillary evidence that supports the credibility of sources of other evidence. Convergent evidence occurs when two or more items of evidence about a different event all seem to favor the same hypothesis.
Thus, at a superficial level, evidence seems uncomplicated. However, lurking just below this superficial level is an ocean of subtlety. Systems and methods for visualizing arguments according to this invention help evidence analysts, such as intelligence analysts, lawyers, judges, juries, scientists and other actors who need to draw conclusions from masses of evidentiary facts, to navigate through these subtleties by capturing key characteristics of facts and evidence with data structures. In various exemplary embodiments, systems or methods for visualizing arguments according to this invention, allow these evidentiary facts to be presented to a user in a dialog and allow the user to organize such evidentiary facts around arguments and hypothesis.
As discussed above, hypotheses are questions or conjectures of interest to an observer. Hypotheses may involve alternative explanations, possible answers, or alternative estimates. One exemplary embodiment of a hypothesis H is “Iraq had weapons of mass destruction (WMD)”. The complimentary hypothesis HC is “Iraq did not have WMD”. Hypotheses such as the ones discussed above seek to provide estimative intelligence regarding political, military, economic and social factors that influence policy makers.
Hypotheses may have substructures. That is, it is sometimes possible to divide, decompose or partition a high-level hypothesis into a set of sub-hypotheses. In various exemplary embodiments, a particular hypothesis can be composed into a hierarchal tree of sub-hypotheses, sub sub-hypotheses, sub-sub-sub-hypotheses and the like. Thus, the hierarchal tree may be several levels deep. Each level can be directly assessed and answered by evidentiary facts regardless of how far down the tree a sub-hypothesis occurs. For example, the hypothesis H outlined above may be decomposed into: H “Iraq had nuclear WMD”, Sub-H: H1 “Iraq had biological WMD”, Sub-H: H2 “Iraq had chemical WMD”, Sub-H: H3 “Iraq had other WMD” and the like. Furthermore, the first sub-hypothesis H1 can be further decomposed into two or more sub-hypothesis, such as Sub-Sub-H: H11 “Iraq had nuclear WMDs in Baghdad” and Sub-Sub-H: H12 “Iraq had nuclear WMDs in Mosul.”
It should be appreciated that the cascading decomposition sequence outlined above is not necessarily unique. Thus, multiple sub-hypothesis may be simultaneously satisfied.
The proof state, or likelihood, of any hypothesis or sub-hypothesis may be captured by the certainty or uncertainty of the evidence credibility and the weight of support the evidence provides to the hypothesis. In various exemplary embodiments of systems and methods for visualizing arguments according to this invention, certainty is represented by a number between 0 and 1 that represents the probability or likelihood that a particular hypothesis or sub-hypothesis is true. In various exemplary embodiments accordingly to this invention, the certainty value of a hypothesis is determined based upon the evidentiary facts associated with a hypothesis, the relevance and credibility of those evidentiary facts and the inferential strength of those evidentiary facts.
An inference is a conclusion that connects evidentiary facts to a hypothesis. Inferences are logical arguments, sometimes referred to as generalizations, which support the conclusion called for in a hypothesis. Inferences may also connect one sub-hypothesis with another sub-hypothesis higher up in the hierarchal tree or with the ultimate hypothesis that lies at the root of the hierarchal tree. A reasoning chain is a sequence of inferences that start with an evidentiary fact and lead to one or more hypothesis. In particular, it should be appreciated that there may be several sub hypotheses within a particular inference chain.
In various exemplary embodiments according to this invention, a particular inference is parameterized by its strengths and its direction. In particular, its strength or inferential force defines how strongly the evidence supports, or disproves or contradicts, a particular hypothesis. The direction defines whether the evidentiary facts support, or disprove or contradict the hypothesis. The inferential force, i.e., the strength or weight, of an inference is related to the credibility and relevance of each of the evidentiary facts that that inference connects to the given hypothesis. For example, evidence with weak credibility and with weak relevance will generally not have strong inferential weight, thereby providing a low level of certainty in the hypothesis.
An argument or inference network is a directed acyclic graph (DAG) that has a plurality of nodes connected by a plurality of edges. The nodes generally represent possible sources of uncertainty, such as, for example, evidentiary facts, sub-hypothesis, the ultimate hypothesis and the like. In contrast, the edges represent the various inferences and/or inference chains.
However, there appears to be no simple way to determine the inferential strength of evidence and inferences in arguments. In fact, determining the inferential strength of arguments has been a goal of legal scholars, scientists, mathematicians and statisticians since at least the 1600's. Unfortunately, there is no commonly agreed-upon technique to determine the inferential strength of evidence and inferences in arguments. In various exemplary embodiments of systems and methods for visualizing arguments according to this invention, Bayesian probabilistic methods are used, where the evidence credibility and hypothesis uncertainty are modeled using a zero-one scale that roughly corresponds to a probability. The relevance of a given inference to a particular hypothesis is then the conditional probability of the hypothesis given the evidentiary facts.
In particular, the likelihood scores for a particular hypothesis are normalized to probabilities. In various exemplary embodiments of systems and methods for visualizing arguments according to this invention, at least two scoring functions or schemes can be used. In a first scoring function, the hypotheses are scored as competing, where only one hypothesis can be true. In this case, the probabilities associated with the hypotheses must sum to one. In a second scoring function, each of a plurality of hypotheses is evaluated independently. Thus, each hypothesis is given a score between zero and one, independently of the probability scores of the other hypothesis.
Constructing an argument is a creative task that involves looking at facts, formulating conjectures, creating hypothesis, associating facts with hypothesis as evidence, creating sub-hypothesis, and iterating these steps. Various exemplary embodiments of systems and methods for visualizing arguments according to this invention allow analysts to perform these steps in an interactive, structured environment that allows each of these actions to be performed independently of the others and that allows the user to repeatedly switch between these actions. In various exemplary embodiments, systems and methods for visualizing arguments according to this invention encourage analysts to explore new hypotheses and alternative explanations for the facts. Various exemplary embodiments of systems and methods for visualizing arguments according to this invention allow facts to be marshaled and organized as evidence around various hypotheses.
In particular, in various exemplary embodiments, systems and methods for visualizing arguments according to this invention allows an analyst to add facts, browse facts and evidence, create hypotheses, associate facts with hypothesis as evidence, set the relevance and credibility of facts and evidence, combine hypotheses, restructure hypotheses, edit previously created arguments, and use traditional proof constructs to capture the inferential structure of the relationships between the evidentiary facts and a given hypothesis. These features, which can be provided in various exemplary embodiments of the systems and methods for visualizing arguments according to this invention, will be described in greater detail with respect to
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The main difference between the hypotheses 1144, the sub-hypotheses 1145 and the conjectures 1146 is their support level. That is, a sub-hypothesis 1145 has evidence that supports a hypothesis 1144, and can be linked to any other hypothesis, i.e., either to a main hypothesis 1144 or to some other sub-hypothesis 1145. Likewise, conjectures 1146 are hypotheses that have not yet been made active hypotheses 1144 by placing them in the active hypothesis portion 1141 or made active sub-hypotheses 1145 by placing them in the active sub-hypothesis potion 1142. The conjecture portion 1143 is used to store-house the analysts' thoughts about possible hypotheses before those possible hypotheses become developed enough to warrant being placed into either the active hypothesis portion 1141 as an active hypothesis 1144 or the active sub-hypothesis portion 1142 as an active sub-hypothesis 1148. A conjecture 1146 may not warrant being placed in to either the active hypothesis portion 1141 or the active sub-hypothesis portion 1142 because insufficient facts can be linked evidentially to that conjecture 1146 or for any other reason where the analyst is not yet ready to treat that conjecture 1146 as a full hypothesis 1144 or sub-hypothesis 1145.
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In various exemplary embodiments, the action widgets 1162-1167 of the argument construction portion 1160 include an add evidence widget 1162, an add sub-hypothesis widget 1163, an add data widget 1164, an add rebuttal widget 1165, an extended Toulmin widget 1166 and a Wigmore widget 1167. The add evidence widget 1162 allows the user to add evidentiary facts and create inferential links from those evidentiary facts to the main hypothesis 1144, a desired sub-hypothesis 1145 or other evidence. In various exemplary embodiments, the evidence is added by selecting a fact displayed in the evidence marshalling portion 1110 and dragging and dropping the selected fact from the evidence marshalling portion 1110 to the desired location in the argument being constructed or edited using the argument construction portion 1160.
The add sub-hypothesis widget 1163 allows the user to select a hypothesis 1144, a sub-hypothesis 1145 or a conjecture 1146 from the hypothesis overview portion 1140 and drag and drop it into a Wigmorean data form shown in the argument visualization portion 1160. The add sub-hypothesis widget 1163 also allows the user to create an inferential link 1147 between that hypothesis 1144, sub-hypothesis 1145 or conjecture 1146 and some previously placed the main hypothesis 1144, some other hypothesis 1144 added as a sub-hypothesis, a sub-hypothesis 1145 or conjecture 1146 added as a main hypothesis or a sub-hypothesis. The add data widget allows the user to add a data element to a Toulminian data form shown in the argument visualization portion 1160. The add rebuttal widget 1165 allows the user to add a rebuttal element to a Toulminian data form shown in the argument visualization portion 1160. The extended Toulmin widget 1166 converts an argument being visualized in the argument visualization portion 1161 from the Wigmorean form to the Toulminian form enables the widgets 1164 and 1165, and disables the widgets 1162 and 1163.
In contrast, the Wigmore widget 1167 converts and displays an argument being visualized in the visualization portion 1161 using the Toulminian form into an argument visualized using the Wigmorean form, enables the widgets 1162 and 1163 and disables the widgets 1164 and 1165. Accordingly, when the Wigmorean form is being displayed, as shown in
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The assumption portion 1174 shows all of the assumptions that have been made explicit about the selected hypothesis 1144. These assumptions are added by selecting the assumptions widget 1156 shown in
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In the exemplary embodiment of the evidence graphical user interface 1180 shown in
In various exemplary embodiments of the evidence graphical user interface 1180, such as that shown in
It should be appreciated that each of these selectable textual values implemented in a drop down box associated with a particular widget has a numerical value between 0.01 and 0.99 associated with it. In various other exemplary embodiments, the range can extend between 0 and 1. These numerical values represent the numerical probability associated with the textual label. For example, the textual label “not very” will likely have a value between 0.01 and 0.10, for example. In contrast, the textual label “definite”, will likely have a value of between 0.85 and 0.99. It should be appreciated that each drop down box could have a different set of textual labels and that each drop down box could, and typically will, have different values associated with the particular labels. In various exemplary embodiments, the values can be assigned by dividing the range between 0.01 and 0.99 into a number of sub sections equal to the number of choices provided in a particular drop down box. In differing exemplary embodiments, the value associated with each textual label could be the minimum value of that range, the maximum value of that range, the average value of that range, the median value of that range, or any other statistical value associated with that range. In one such exemplary embodiment, the values associated with the plausibility textual labels could be, for example, 0.1, 0.3, 0.5, 0.7 and 0.9 for the textual labels “not very close”, “questionable”, “moderately”, “very likely”, and “definite”, respectively.
In contrast, in various other exemplary embodiments, the values associated with each of the textual labels provided in a given drop down box can be specifically selected to best represent the value that the average analyst places on that particular textual label. Thus, in practice, in such a situation, two labels, such as, for example, “not likely” and “questionable” may be separated by only 0.03, while two labels such as, for example, “moderately” and “very likely” might be separated by 0.25 or more.
Once each of the implemented parameters has a particular textual label or numerical value selected for it, depending upon the particular implementation, a overall value for the source credibility and the overall applicable of the evidentiary fact is generated based on the parameters associated with the source, such as reliability, proximity and appropriateness, while an applicability score is generated based on the values associated with the plausibility, expectability and support parameters. Alternatively, all of the parameters can be combined into a simple credibility value.
When a document 2210 is displayed in the graphical user interface 2200 of the word processing program, a portion 2100 of that document can be selected as a fact to be supplied to the systems and methods for visualizing arguments according to this invention. After opening the tool bar 2000 and selecting the section of text 2100, the tool bar 2000 can be used to provide values for various evidentiary parameters 2183-2188 that correspond to the evidentiary parameters 1183-1188 discussed above with respect to
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The node-size widget 1212 and the edge-size widget 1213 allow the sizes of the nodes and the edges to be scaled based on the credibility and relevance values associated with an inference link linking an evidentiary fact 1121 to a hypothesis 1144 or sub-hypothesis 1145 or the inferential strength of an inference that extends from a sub-hypothesis 1145 to another sub-hypothesis 1145 or to the main hypothesis 1144. When the node-size widget 1212 or the edge-size widget 1213 is at the left edge, the node and edge size is completely independent of the credibility or inference score for that node or edge. In contrast, when the node-size and edge-size widgets 1212 and 1213 are at the full right hand edge, the size of the nodes and edges are solely functions of the associated scores.
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The color scale widget 1214, if checked, scales the color based on the user's preference. Finally, the certainty and uncertainty selection widgets 1215 and 1216 allow the scoring of the visualized argument to be switched between an uncertainty value and a certainty value.
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In various exemplary embodiments, the name portion 1610 displays the current name of the selected hypothesis 1144, sub-hypothesis 1145 or conjecture 1146. The assumptions portion 1620 includes an add/edit assumption portion 1622, a previously defined assumption portion 1624, and add action widget 1626 and a remove action widget 1628. As shown in
In contrast, if the user wishes to delete a previously added assumption, the user can highlight one of the previously added assumptions shown in the previously defined portion 1624 and can click on the remove action button 1628. If the user merely wishes to edit one of the previously added assumptions, double clicking on that assumption will bring it up in the add/edit portion 1622.
In the exemplary embodiment of the hypothesis assumptions graphical user interface 1600 shown in
In various exemplary embodiments, the selected hypothesis region 1310 is divided into a number of sub-regions equal to the number of selected hypotheses, with one selected hypothesis associated with each sub-region. For each selected hypothesis, the name 1311 of that selected hypothesis, a score value 1312 for that selected hypothesis, and a scoring bar graph 1313 for that selected hypothesis is displayed in the sub-region associated with that selected hypothesis. The score value 1312 provides a numerical indication of the certainty or likelihood that that hypothesis is correct, while the bar graph 1313 provides a graphical or visual representation of the score of that hypothesis. It should be appreciated that this score can be determined using Bayesian, Dempster-Schaeffer, Baconian or other probabilistic methods.
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For each of the hypothesis columns 1323 for a given fact item 1321, if that fact item has not been associated with the corresponding hypothesis for that hypothesis column 1323, then the cell for that fact item row and that hypothesis column is left blank. Otherwise, if that fact item 1321 has been associated by an inferential link either directly or indirectly with the hypothesis, making it an evidentiary fact with respect to that hypothesis, that cell will display one or more pieces of information based on a control selection made using the control portion 1330.
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When a hypothesis 1144 or 1145 is in the selected state, such as for the hypotheses “Mohammed,” “Explosive,” “Boston,” “NYSE,” or “New Orleans,” that hypothesis is added in a new sub-region to the selected hypothesis region 1310, such that its name, its score value and a corresponding bar graph are displayed. When a particular hypothesis 1144 or 1145 displayed in the hypothesis selection widget 1331 is deselected, it is removed from the selected hypothesis region 1310 and its column in the fact element table 1320 is removed from the display.
It should be appreciated that, in various exemplary embodiments, adding newly selected hypotheses 1144 or 1145 or removing newly deselected hypotheses 1144 or 1145 causes the widths of the hypotheses columns for the selected hypotheses to change. In various other exemplary embodiments, each of the selected hypotheses columns has a fixed column width. In this case, if adding additional selected hypotheses causes the overall width of the selected hypothesis region 1310 and the fact element table 1320 to be wider than the available display area, a horizontal scroll bar is implemented for at least the sub regions of the selected hypothesis region 1310 and the corresponding hypothesis columns 1323.
In various exemplary embodiments, the score function widget 1332 allows the user to select between at least two different scoring functions. In various exemplary embodiments, these at least two different scoring functions include at least a Competing Hypotheses scoring function and a Multiple Hypotheses scoring function. When the Multiple Hypotheses scoring function is selected, any number of hypotheses can receive a high score. Accordingly, each of the hypotheses is scored between 0 and 1, based on its overall likelihood of being correct, independent of the scores associated with any of the other selected hypotheses.
When the Competing Hypotheses scoring function is selected, as shown in
In various other exemplary embodiments, the sum of the values associated with each of the selected hypotheses represents the likelihood that at least one of these selected hypotheses is right. This allows analysts to determine if other hypotheses should be considered. For example, when the sum of the scores associated with the selected hypotheses is less than 50%, a residual hypothesis or alternative explanation is probable and reflected with the remaining evidence, which has not been associated, being associated with a “residual” hypothesis. This situation is shown in the exemplary embodiment shown in
When the cell visualization widget 1333 is selected, a drop down box is displayed that allows the user to select the particular information to be displayed in each of the hypotheses columns 1323 of the fact element table 1320. In the exemplary embodiment shown in
The relevance-strength selection widget 1335 includes a drop down box that allows the user to select whether all relevant items are displayed, only cells having positive values, corresponding to fact items that support the corresponding hypothesis, or cells having negative value, corresponding to fact items that tend to disprove or contradict the corresponding hypothesis.
When the show depth check box 1336 is checked, each of the cells in the hypothesis columns 1323 additionally shows the depth at which that fact item 1321 is connected, either directly or indirectly to the corresponding hypothesis. For example, if a fact item is directly connected to the corresponding hypothesis, its depth level is one. In contrast, if that fact item is connected to a sub-hypothesis, which is connected to that hypothesis, then the depth is two, and so on.
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It should be appreciated that, unlike the credibility score, in the exemplary embodiment shown in
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In each case, the link analysis visualization 1520 includes a plurality of facts 1522, links 1523 between various ones of the facts 1522, and other sets of facts 1521 that the facts 1522 may have been linked to. In the particular set of linkages visualized in the particular exemplary embodiment of the link analysis visualization 1520 shown in
As discussed above, in the link analysis visualization 1520 shown in
In contrast, to situations where the multiple evidentiary items both support or both disprove a particular hypothesis, when two evidentiary items 3100 are directly connected to a hypothesis, but one supports it while the other tends to disprove it, those evidentiary items are referred to as dissidently contradictive facts. When two evidentiary items 3100 each directly support different sub-hypotheses, but one sub-hypothesis supports a main hypothesis but the other sub-hypothesis tends to disprove the main hypothesis, the evidentiary facts are referred to as dissidently conflicting facts. Finally, when a first evidentiary fact supports a sub-sub-hypothesis and that sub-hypothesis and another evidentiary fact both support a sub-hypothesis, while both of the sub-sub-hypothesis and the sub-hypothesis also directly support a main hypothesis, those evidentiary facts are referred to as redundantly cumulative facts. Based on these enhanced judicial proof forms, analysts can easily create Wigmorean diagrams such as those shown in
Each of the sub-hypotheses 4300 and 4310 is linked by an inferential link 4302 and 4312, respectively, to a main hypothesis 4500. As shown in
Also connected to the claim or hypothesis 5500 that “Harry is a British citizen,” is a rebuttal 5600 connected to the claim or hypothesis 5500 by a contradictory inferential link 5610. In the exemplary embodiment shown in
As outlined above, in various exemplary embodiments, the argument visualization systems and methods according to this invention use Bayesian probabilistic methods to score the various different hypotheses based on the arguments built around those hypotheses. In various exemplary embodiments, the evidence credibility and hypothesis uncertainty is modeled using a scale from 0.0 to 1.0 that roughly corresponds to a probability value. In general, the inferential strength of an inference extending from an item of evidence to a hypothesis or sub-hypothesis is then the product of the relevance of that evidence to that hypothesis times the credibility of that evidence. The strength or inferential force of an inference thus indicates how strongly the evidence supports the hypothesis. The sign on the relevance and thus the direction of that evidence, i.e., whether it supports or contradicts the hypothesis, determines whether the inferential strength is positive or negative.
Under the standard rules of Bayesian probabilistic methods, inferences and uncertainty propagate a long chain of inferences using standard rules of conditional probability. For example, the certainty or probability of a sub-hypothesis H1, represented as P(H1|E1), in view of an evidentiary fact E1, is:
P(H1|E1)=CE1*RE1|H1 (1)
CE1 is the credibility of an evidentiary fact E1; and
RE1|H1 is the relevance of the evidentiary fact E1 to the sub-hypothesis H1.
Then, when the sub-hypothesis H1 that has multiple pieces of evidence inferentially linked to it, the certainty or probability P(H1|E1,E2) of the hypothesis H1, in view of two evidentiary facts E1 and E2, is:
P(H1|E1,E2)=CE1*RE1|H1+CE2*RE2|H1−CE1*RE1|H1*CE2*RE2|H1; (2)
where:
CE2 is the credibility of the second evidentiary fact E2 that is inferentially linked to the sub-hypothesis H1; and
RE2|H1 is the relevance of the evidentiary fact E2 to the sub-hypothesis H2.
It should be appreciated that this is simply the conditional probability that the sub-hypothesis H1 is true given that the various inferentially-linked evidentiary facts such as, for example, E1 and E2, are independent of each other. Of course, it should be appreciated that if the evidentiary facts are not independent of each other, or more accurate solutions are desired, more sophisticated Bayesian, Dempster-Schaeffer, Baconian or other probabilistic methods can be used.
In probabilistic terms, the relevance RX|Y encodes the conditional probability that the hypothesis X is justified given that the evidentiary fact or sub-hypothesis Y is true. For an inference chain through a plurality of sub-hypotheses, the certainty of the hypothesis is equal to the product of the credibility of the underlying evidentiary fact multiplied by the relevance of each of the inferential links between that piece of underlying evidentiary fact and the ultimate hypothesis. Thus, if a hypothesis H2 is inferentially supported by the sub-hypothesis H1, where the inferential link between the sub-hypothesis H1 and the hypothesis H2 has a relevance RH2|H1, the certainty P(H2|H1) of the hypothesis H2 is:
P(H2|H1)=CH2*RH1|H2=CE1*RE1|H1*RH1|H2 (3)
As shown in
As shown in
The certainties of the H3 and H5 sub-hypotheses 6310 and 6320 can then be determined. In particular, the relevance of the inferential link 6600 between the H2 sub-hypothesis 6500 and the H3 sub-hypothesis 6310 is 0.75, while the relevance of the inferential link 6610 between the H2 sub-hypothesis 6500 and the H5 sub-hypothesis 6320 is also 0.75. Accordingly, the certainties 6314 and 6324 of the sub-hypotheses 6310 and 6320 in view of the sub-hypothesis 6500 is P(H31H2)=0.5 and P(H51H2)=0.5. At the same time, as indicated above, the certainties 6312 and 6322 of the sub-hypothesis 6310 in view of the evidentiary fact 6100 are P(H3|E)0.95 and P(H3|E)0.6. The total or combined certainty of the sub-hypothesis 6310 is thus P(H3|H2,E)=0.975. Similarly, the total certainty 6522 of the H5 sub-hypothesis 6320 is P(H5|H2,E)=0.8. It should be appreciated that the rest of the analysis can be performed by applying equations 1-3 to the remaining inferential links. For the argument or Bayesian belief network shown in
In step S400, a desired hypothesis and zero, one or more sub-hypotheses are arranged and linked together and a number of the supplied fact items are linked to the selected hypothesis, sub-hypotheses and/or previously linked fact items using inference links to create a visualized argument, as outlined above with respect to
Once at least some of the fact items, which become evidentiary facts when linked to various other hypotheses, sub-hypotheses and/or other facts, are provided with credibility scores and the inferential links between the evidentiary facts, the sub-hypotheses and the hypothesis are given relevance values, the argument built around the main hypothesis can be scored to generate a certainty value for that main hypothesis in step S600. Then in step S700, one or both of steps S200 and S300 can be repeated along with steps S400-S600 to create and score one or more additional arguments. Additionally, it should be appreciated that, as additional facts become available and/or the significance of previously underappreciated facts becomes apparent, steps S200, S400 and S500 can be repeated to add such new facts into a current argument, with step S600 being repeated to rescore that argument. Operation of the method then continues on to step S800.
In step S800, one or more of the arguments created in steps S600 and S700 can be compared and scored, either independently or competitively, to compare and test the arguments against themselves and each other. It should be appreciated that the arguments can be compared on any desired basis, such as, for example, which analysts created the arguments, who collaborated on creating the arguments, which organization and/or individual commissioned the argument, the date the argument was created, last modified, or the like. In step S900, the user can modify the visualized argument based on new hypotheses, sub-hypotheses and/or fact items by repeating at least steps S400, S600 and S800 and also by repeating steps S200, S300, S500 and S700 as well. In particular, the analyst will complete various ones of steps S200-S900 until the analyst is satisfied that the analyst has adequately supported a selected hypothesis for building the appropriate argument around it.
While
It should be appreciated that, in various exemplary embodiments, the argument visualization graphical user interface and methods for visualizing an argument according to this invention can use argument templates that allow an analyst to more easily construct a particular argument. These templates can correspond to the types of problem, such as a criminal investigation, a foreign policy analysis, a military analysis or the like. These templates can also correspond to the type of analysis to be performed, such as a process analysis, an event analysis, a predictive analysis, an explanative analysis, a descriptive analysis, an investigative analysis or the like. It should also be appreciated that a “wizard”-type software element could be used to lead an analyst through at least the initial stages of constructing an argument, or even could be used to at least initially create hypotheses, sub-hypotheses and conjectures, create and/or gather potentially relevant facts, and link them together into at least an initial form of an argument.
It should also be appreciated that, in various exemplary embodiments, the changes, revisions, additions, deletions, and possibly the person making such changes, can be tracked, similarly to the “Track Changes” feature of Microsoft Word™. This allows a user, such as a subsequent analyst, or a decision-maker, to see how a particular argument has changed through time. In various exemplary embodiments, the various tracked changes can be automatically shown in rapid succession, similarly to an animation, that allows the viewer to experience how the argument has evolved over time. In various exemplary embodiments, a similar feature can be used to trace the path of a piece of fact and/or evidence.
While this invention has been described in conjunction with the exemplary embodiments outlined above, various alternatives, modifications, variations, improvements, and/or substantial equivalents, whether known or that are or may be presently unforeseen, may become apparent to those having at least ordinary skill in the art. Accordingly, the exemplary embodiments according to this invention, as set forth above, are intended to be illustrative, not limiting. Various changes may be made without departing from the spirit and scope of the invention. Therefore, the invention is intended to embrace all known or later-developed alternatives, modifications variations, improvements, and/or substantial equivalents of these exemplary embodiments.
This application claims priority to U.S. Provisional Patent application 60/658,666, filed Mar. 3, 2005, which is incorporated herein by reference in its entirety.
The subject matter of this application was made with U.S. Government support awarded by the following agencies, National Geospatial Intelligence Agency under contract number HM158204-C-0021. The United States has certain rights to this application.
Number | Date | Country | |
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60658666 | Mar 2005 | US |