The phenomenaof natural sciences’ account laid down by scientific thinking and knowledge arenot just a simple explanation of what the world around us is like but insteadit is a more of an extensive and systematic description that consists of bothempirical and non-empirical evidence of these phenomena. The Deductivenomological; method is a scientific explanation, however, according to Hempel,not all “description” and “explanation” are scientific explanations.
What makes the D-N model different? The D-N includes an explicandum that isgoing to explain the event that will be described, and an explicans,explanations for the given phenomenon. In Aspects ofScientific Explanation and other Essays in Philosophy of Science, Hempelgave conditions for which the explicans can effectively describe theexplicandum. He maintained that “the explicandum must be a logical consequenceof the explicans”, also, “the sentencesconstituting the explicans must be true” (Hempel 1965). He furthered by sayingthat the explicans has to have at least one law of nature included. This lawwill serve as a central premise that if it were to be removed, the explicandum wouldn’tremain valid. Hempel based his criteria on havinga set of true propositions that correspond to facts (E statement). According to Hempel, the relationship can be statedas:Initialconditions: C1, C2,..
…CnLaws:L1, L2, …, LnExplainedevent: ETo show this how theD-N model works, for example in a situation where event E represent that the leaves fell from the tree. It is possible thatthe initial conditions could be that the weather was windy, it was really hotand dry which weakens the stem and later causes the leaves to fall, change ofseason and when leaves start photosynthesizing. The natural law could be thetemperature rising above 90 degrees or dropping below 0 degrees and pressurefalls below that level. Hempel’srequired that every scientific explanation will be covered by at least one lawof nature, and the explanation will then ‘cover’ the initial conditions and theexplained event. Hempel laid out the conditions for the natural laws for it tobe valid.
He claims that the laws must have a mechanism, the truth of allpropositions to the scientific explanation must follow deductively from theproposition in the condition, the terms must have empirical import etc. (Hempel 1965, p. 338-39). Withthese laid down conditions, the demarcation between science and non-sciencesurfaced. Science as we know deals with empirical certainties that are free ofbiased explanations and deductions, and logical truths. The idea of a critical social theory andscientific explanation has been a long on-going controversy that has split thesocial scientist apart from natural scientist. The natural scientists claim thatthe methods of natural sciences and scientific explanations, which have broughtabout huge and advanced discoveries, are the only scientific explanations thatshould be applied to the whole study of human affairs.
The social scientists propoundsthat there is a basic difference in the structure of the social sciences andnatural sciences. I support the latter. According to Alfred Schutz and otherphenomenologists, it is emphasized that social sciences cannot remain faithfulto its subject matter and at the same time we satisfy the principles ofprocedures (scientific methods/explanations) set by positive science (Pg 257).Therefore something about the explanation methodology has to be different.Perhaps a difference in the structure formation, or even creating a moreefficient explanation structure might eliminate the conflict of the subjectmatter and the principles of scientific methods. While the D-N model separates the socialscience through its scientific nature, it ignores that the social science couldpossibly be capable of forming objective concepts and using differentverification methods in its assessment. Deductive nomological method separates thescience from the non-science in the sense that we know that motives, reasons,emotions and some subjectivity are recurring patterns seen in the socialstudies, and they have been theorized to have an effect on observations andscientific explanation. However, these patterns have been ignored and beingignored because they are placed on an ambivalent and insufficient basis toconsistently fit the D-N model.
Anadequate scientific explanation cannot always be given in principal for thephenomena in social sciences without using motives, reasons or addressing theissues based on its individuality. Social science unlike natural science lacksuniversality and that in itself is the loose end that cannot fit in thedeductive nomological method. There isno doubt that great accomplishments have been made through scientific explanationsto achieve definite answers to some of the toughest problems in the naturalsciences and also other concentrations.
However it is different for socialsciences. Human affairs and social methodology are based on inter-subjectivity.The theoretical ideals of natural sciences and scientific precision involved inthe D-N is too strong to capture the conception of social sciences orinsufficient for social formulations. Thestructure and conditions that are followed in the natural science would(including the D-N) are replicable and sometime doesn’t to need a concretefield knowledge to guarantee its certainty.
For example a diverse panel ofcompetent people, are provided with raw observed data collected to predict thecause of depression, and another diverse group of competent people are given observeddata collected to measure the heat capacity of copper. Both panels are notexperts in these field but they are to follow the given data and instructions. Withthese two groups, there are no superficial requirements such as high IQ scoresor high GPA (3.8 minimum) used to test their competency. They are provided withthe same background knowledge and training.
My hypothesis is that because of thestructure used in the natural science world, the “copper” panel will have amore uniform answer than the “depression” panel. Naturalscience captures the same scientific terminology/language, theories and laws,interpretation of the data which produces uniformity than social science. The issuesin social science becomes problematic when different component of the D-Ncannot be fulfilled or doesn’t not exists in the field. Diversity, such as judgment due todifferences in introspection and constructs makes the social science world moreopen. Social scienceis not a good fit for the deductive nomological model because human behaviorsand motives cannot be categorized into one specific spectrum which is whysocial sciences unlike natural science tend to be less rigid in its structurethus separating it from the natural science. Furthermore, there are additional underlyingrelations that are often unknown to the observer doing observation. Theexternal causation of a subject could be due to psychological states, temporalemotions and/or even internalization of schemes unlike in natural science.
Lettake a scenario of a psychological researcher. Suppose his focus and showsinterest in emotions, he may need to take into account the hormonal activitiesin each subject. Not just go by a standard data or some universal hormonalmeasurement. He must also simultaneously consider other impulsive actions madeby his subjects. Since the socialscience cannot work in accordance with the structure of the natural science togive adequate scientific explanation, field such as psychology that lies in theborderline tries to use a different method more suitable for its genre in itsexplanation instead of the structure of natural sciences to explain concepts inits field. Psychology has created a more suitable explanation structure tolessen contradiction, linguistic phenomenon and formation in order to fitbetter in the natural science world.
Even with this adjustment and improvementmade by psychology, would it still be able to follow the D-N model? Using psychology as an example, let us see ifthe D-N model could be utilized. Based on the definition given by mayoclinic, “post-traumatic stress disorder (PTSD) is a mental health conditionthat’s triggered by a terrifying event — either experiencing it or witnessingit. Symptoms may include flashbacks, nightmares and severe anxiety, as well asuncontrollable thoughts about the event”. The explanation given by Mayo’s clinic for post-traumaticstress disorder according to the D-N is not a scientific explanation. It isvery vague without a solid scientific structure. If at all it has one, then it isnot a solid one.
The problem here with both Hempel’s D-N criteria and PTSD/mostpsychological disorders is that according to the model of explanation, there isno way you can escape the subjective aspect of individualistic cases. According to Hempel, “what scientific explanation especially theoreticalexplanation aims is not an intuitive andsubjective kind of understanding but an objective kind of insight that isachieved by a systematic unification, by exhibiting the phenomena asmanifestable, basic principles” (Hempel 1966, pg. 83). He saidexplanations and predictions are actually the same and the only difference isin respect to when the particular explicandum occurs. (Sec 5.2) Then if thatwas the case, it can be said that if the DN is an account of scientificexplanation, therefore anything that can be explained can be equally predicted.
That is the part where some issues come in. What about the situations whereby explanationsare scientifically acceptable but do not have natural laws to back them up orexplain them? Hempel will say, “Then they are not scientifically acceptable orexplained.” The same goes for PTSD and the unknown laws. The scientificdata and criteria for diagnosing PTSD is not accurate or better still completeaccording to Hempel’s scientific explanation.
It is also missing fundamentalprinciples that necessitate the conditions for “scientific explanation” suchas; an explanation that contains at least one proposition expressing a generalof nature, it also says that the explanandum should not follow from the non-lawfulproposition of the condition alone. The biggest one I think that the PTSDexplanation is missing is that “the law as given in the scientific explanationshould not only be true but also in fact is/are law(s) of nature according toour best science. Mayo’s clinic explanationsfor PTSD satisfy the deductive aspect of Hepel’s criteria but are weak and didnot necessarily satisfy the nomological part. The data for diagnosing PTSD and mostpsychological disorder does not have background laws that give it the full”scientific explanation.” There is no law for PTSD just assumptions based onsubjectivity and inter-subjectivity. The methodology of the diagnostic processis weak which somewhat depended on the subjectivity of the psychologist ormedical professional doing the diagnosis. These bring about the question ifnatural science criteria can be applied to all aspects of psychology or if someof the areas in psychology are just plain pseudoscience.
Main symptoms ofPTSD like intrusive memory, avoidance, change in emotional reactions can bewell justified by research, brain chemistry and other subjective observationbut other symptoms and causes are no based on fundamental natural laws that wouldmake PTSD scientifically acceptable to Hempel. These methods will not giveprofound result in all cases which jeopardizes the prediction clause ofHempel’s criteria. There are certain correlations but it is not proven to bethe causation.