Glossary
Abduction
Syllogism in which one premise is certain and the other one is only probable, generally presented as the best explanation to the former. Hence, abduction is a type of reasoning in which we know the law and the effect, and we attempt to infer the cause.
Deduction
Process of reasoning that moves from the general to the specific and in which a conclusion follows necessarily from the stated premises. Hence, deduction is a type of reasoning in which, knowing the cause and the law, we infer the effect.
Forensic intelligence
Understanding of how traces can be collected from the scene, processed, and interpreted within a holistic, intelligence-led policing strategy.
Heuristic
Process of reasoning by rules that are only loosely defined, generally by trial and error.
Holistic
Emphasizing the importance of the whole and the interdependence of its parts.
Induction
Process of deriving general principles from particular facts or instances (i.e., of reasoning that moves from the specific to the general). Hence, induction is a type of reasoning in which, knowing the cause and the effect (or a series of causes and effects), we attempt to infer the law by which the effects follow the cause.
Linkage blindness
Organizational or investigative failure to recognize a common pattern shared on different cases.
Science
The intellectual and practical activity encompassing the systematic study of the structure and behavior of the physical and natural world through observation and experiment. It is also defined as a systematically organized body of knowledge on a particular subject.
Given that it identifies and collects objects at crime scenes and then treats them as evidence, forensic science could appear at first glance to be only a pragmatic set of various disciplines, with practitioners adapting and developing tools and technologies to help the triers of fact (juries or judges) interpret information gained from the people, places, and things involved in a crime. The view could beâand has beenâheld that forensic science has no philosophic or fundamental unity and is merely the application of knowledge generated by other sciences. Indeed, many working forensic scientists regard themselves mainly as chemists, biologists, scientists, or technicians and rarely as practitioners of a homogeneous body of knowledge with common fundamental principles.
Even the 2009 National Academy of Sciences National Research Council Report failed to recognize such a concept, certainly blurred by a semantic gap in the terminology itself of field practitioners, who confuse words such as âforensic science(s),â âcriminalistic(s),â âcriminology,â âtechnical police,â âscientific police,â and so on and generally restrict the scientific debate on analytical techniques and methods. An independent definition of forensic science, apart from its legal aspects, would support its scientific status and return the expert to his domain as scientist and interpreter of his analyses and results to assist the lay person.
What Is Forensic Science?
In its broadest sense, forensic science describes the utility of the sciences as they pertain to legal matters, to include many disciplines, such as chemistry, biology, pathology, anthropology, toxicology, and engineering among others. (âForensicâ comes from the Latin root forum, the central place of the city where disputes and debates were made public to be solved, hence, defining the law of the city. Forensic generally means âof or applied to the law.â) The word âcriminalisticsâ was adopted to describe the discipline directed toward the ârecognition, identification, individualization, and evaluation of physical evidence by application of the natural sciences to law-science matters.â (âKriminalistikâ was coined in the late nineteenth century by Hans Gross, a researcher in criminal law and procedure, to define his methodology of classifying investigative, tactical, and evidential information to be learned by magistrates at law schools to solve crimes and help convict criminals.) In the scheme as it currently stands, criminalistics is part of forensic science; the word is a regionalism and is not universally applied as defined. Difficulties in differentiating the concepts certainly invited the definition of criminalistics as the âscience of individualization,â isolating this specific epistemologically problematic core from the other scientific disciplines. Individualization, the concept of determining the sole source of an item, enthroned a linear processâidentification or classification on to individualizationâlosing sight of the holistic, variable contribution of all types of evidence. Assessing the circumstances surrounding a crime, in which the challenge is to integrate and organize the data to reconstruct a case or propose alternative propositions for events under examination, requires multiple types of evidence, some of which may be quite nuanced in their interpretation. This is also true in the use of so-called forensic intelligence, which feeds investigative, police, or security needs, in which one of the main reasons for failures is linkage blindness. Nevertheless, it seems that the essence of the forensic daily practice is hardly captured within the present definitions of both terms.
Forensic science reconstructsâin the broadest senseâpast criminal events through the analysis of the physical remnants of those activities (evidence); the results of those analyses and their expert interpretation establish relationships among people, places, and objects relevant to those events. It produces these results and interpretations through logical inferences, induction, abduction, and deduction, all of which frame the hypothetico-deductive method; investigative heuristics also play a role. Translating scientific information into legal information is a particular domain of forensic science; other sciences must (or at least should) communicate their findings to the public, but forensic science is often required by law to communicate their findings to public courts. Indeed, as the Daubert hearing stated, âscientific conclusions are subject to perpetual revision as law must resolve disputes finally and quickly.â This doubly difficult requirement of communicating to the public and to the law necessitates that forensic scientists should be better communicators of their work and their results. Scientific inferences are not necessarily legal proofs, and the forensic scientist must recognize that legal decisions based, in part, on their scientific work may not accord with their expert knowledge. Moreover, scientists must think in probabilities to explain evidence given possible causes, whereas jurists must deal in terms of belief beyond reasonable doubt. As Inman and Rudin state, âBecause we [the scientists] provide results and information to parties who lack the expertise to independently understand their meaning and implications, it is up to us to furnish an accurate and complete interpretation of our results. If we do not do this, our conclusions are at best incomplete, at worst potentially misleading.â
The Trace as the Basic Unit of Forensic Science
The basic unit of forensic science is the trace, the physical remnant of the past criminal activity. Traces are, by their very nature, semiotic: They represent something more than merely themselves; they are signifiers or signs for the items or events that are its source. A fiber is not the sweater it came from, a fingerprint is not the fingertip, soot in the trachea is not the victim choking from a fire, blood droplets are not the violence against the victim, but they all point to their origin (source and activity) to a greater or lesser degree of specificity. Thus, the trace is a type of proxy data (i.e., an indicator of a related phenomenon but not the phenomenon itself). Traces come from the natural and manufactured items that surround us in our daily lives. Traces are, in essence, the raw material available at a crime scene that becomes forensic intelligence or knowledge. Everyday items and their traces become evidence through their involvement in criminal activities; the activities add meaning to their existing status as goods in the world; a fireplace poker is transformed into âthe murder weaponâ by its use as such. The meaning added should also take into account the context of the caseâthe circumstance...