Simpson's Paradox and Causality

There are three questions associated with Simpson’s Paradox (SP): (i) Why is SP paradoxical? (ii) What conditions generate SP?, and (iii) What should be done about SP? By developing a logic-based account of SP, it is argued that (i) and (ii) must be divorced from (iii). This account shows that (i) and (ii) have nothing to do with causality, which plays a role only in addressing (iii). A counterexample is also presented against the causal account. Finally, the causal and logic-based approaches are compared by means of an experiment to show that SP is not basically causal

Lost in Translation? The Upaniṣadic Story about “Da” and Interpretational Issues in Analytic Philosophy

In the Bṛhadāraṇyaka Upaniṣad, one of the principal Upaniṣads, we find a venerable and famous story where the god Prajāpati separately instructs three groups of people (gods, humans, and demons) simply by uttering the syllable “Da.” In this paper, our concern is not with ethics but theories of meaning and interpretation: How can all divergent interpretations of a single expression be correct, and, indeed, endorsed by the speaker? As an exercise in cross-cultural philosophical reflection, we consider some of the leading modern theories of meaning—those of Grice, Quine, and Davidson—in order to see if the Upaniṣadic story receives a natural home in any of them. We conclude that the story is best understood through Grice’s theory of meaning rather than Quine’s or Davidson’s

Are Scientific Models of life Testable? A lesson from Simpson's Paradox

We address the need for a model by considering two competing theories regarding the origin of life: (i) the Metabolism First theory, and (ii) the RNA World theory. We discuss two interrelated points, namely: (i) Models are valuable tools for understanding both the processes and intricacies of origin-of-life issues, and (ii) Insights from models also help us to evaluate the core objection to origin-of-life theories, called “the inefficiency objection”, which is commonly raised by proponents of both the Metabolism First theory and the RNA World theory against each other. We use Simpson’s Paradox (SP) as a tool for challenging this objection. We will use models in various senses, ranging from taking them as representations of reality to treating them as theories/accounts that provide heuristics for probing reality. In this paper, we will frequently use models and theories interchangeably. Additionally, we investigate Conway’s Game of Life and contrast it with our SP-based approach to emergence-of-life issues. Finally, we discuss some of the consequences of our view. A scientific model is testable in three senses: (i) a logical sense, (ii) a nomological sense, and (iii) a current technological sense. The SP-based model is testable in the first two senses but it is not feasible to test it using current technology

Truths about Simpson's Paradox - Saving the Paradox from Falsity

There are three questions associated with Simpson’s paradox (SP): (i) Why is SP paradoxical? (ii) What conditions generate SP? and (iii) How to proceed when confronted with SP? An adequate analysis of the paradox starts by distinguishing these three questions. Then, by developing a formal account of SP, and substantiating it with a counterexample to causal accounts, we argue that there are no causal factors at play in answering questions (i) and (ii). Causality enters only in connection with action

Tuberculosis masquerading as oral malignancy

Tuberculosis of the oral cavity is a rare condition. A 55-year-old labourer was referred as a case of oral cancer for further management. The patient had no systemic symptoms. Biopsy of the lesion revealed caseating granulomatous inflammation. Chest X-ray and sputum revealed evidence of asymptomatic pulmonary tuberculosis. The purpose of this paper is to sensitize clinicians to consider oral tuberculosis as a differential diagnosis in patients with an Non-healing oral cavity ulcer

Original Article - Squamous cell carcinoma of the maxillary sinus: A Tata Memorial Hospital experience

Background: The optimal treatment of maxillary sinus carcinoma remains to be defined and there is a paucity of Indian studies on the subject. Aims: To present experience of management of squamous cell carcinoma of the maxillary sinus treated with curative intent at a single institution. Settings and Design:Retrospective study of patients with squamous cell carcinoma of the maxillary sinus who presented between 1994 to 1999. Materials and Methods:The records of 73 patients with squamous cell carcinoma of the maxillary sinus were analyzed. Sixty-two patients were evaluable. Forty patients (65%) were treated with surgery followed by postoperative radiotherapy, five patients (8%) were treated with radiotherapy alone, five patients (8%) were treated with surgery alone; 12 patients (19%) received chemotherapy. Statistical analysis used: Statistical analysis was done using Kaplan-Meier method. Results: The majority of patients presented with locally advanced disease (52, 84%); nodal involvement was observed in five patients (8%). The most common site of recurrence was at the primary site, which was observed in 28 patients (45%) and regional failures occurred in 10 (16%). The 3 and 5-year overall survival was 38% and 35% and the disease free survival was 29% and 26% respectively. The 5-year overall survival after surgery and postoperative radiotherapy was 42%. Conclusions:The majority of patients present with advanced disease resulting in poor outcomes to conventional treatment modalities. Locoregional tumor progression remains a significant pattern of failure. New approaches such as neoadjuvant or concomitant chemoradiotherapy with aggressive surgery need to be considered and evaluated in prospective studies

Case Report - Hemangioma of base of tongue

Although vascular malformations of the tongue comprise a significant portion of head and neck angiodysplastic lesions, hemangioma of base of tongue is rare. We report a case of hemangioma of base of tongue extending to the supraglottis, which necessitated an extended supraglottic laryngectomy. Patient had an uneventful recovery and at three year, follow-up has a normal speech and no difficulty in swallowing or aspiration. More importantly, there was no recurrence of hemangioma or bleeding. Although hemangiomas may be treated by various conservative methods, occasionally patient may require surgical excision as in the present case due to the repeated bleeding episode and difficult access. A high index of suspicion and radiological investigations should be performed if the clinical presentation is atypical for malignancy, as in our case