Stages in Theory and Experiment. Fuzzy-Structuralism and Piagetian Stages.

The theory of stages in cognitive development is one of Jean Piaget's enduring legacies, but it has also borne the brunt of much criticism. It maintains that intelligence develops in an invariant sequence of stages, and, in this paper, I situate Piaget's conceptions of stages historically and functionally in the context of genetic epistemology, his research programme. I highlight some of the objections raised, and I show how the disparity between the conceptions of theoretical and empirical stages in Piaget's theory is commensurate with the fuzzy-structuralist model of the relationship between theory and empirical research conceived by Rudolf Seising on the basis of Lofti A. Zadeh's fuzzy set theory. Further, I propose a fuzzy conception of the notion 'stage', which not only captures its ordinary use in fuzzy space between theory and empirical research but also does justice to both the construct validity and quantitative variability of stages in empirical research. I therefore open a fuzzy-structuralist perspective on the Crisis of Variability afflicting Piaget's stage theory during the 1970s and conclude retrospectively that the rift it caused was not necessary since the invariance and variability of stages is not irreconcilable.

High-dose chemotherapy for relapsed germ cell tumours: outcomes in low-volume specialized centres.

OBJECTIVE: To report treatment patterns and survival outcomes of patients with relapsed and refractory metastatic germ cell tumours (GCTs) treated with high-dose chemotherapy (HDCT) and autologous stem-cell transplantation in low-volume specialized centres within the widely dispersed populations of Australia and New Zealand between 1999 and 2019. PATIENTS AND METHODS: We conducted a retrospective analysis of 111 patients across 13 institutions. Patients were identified from the Australasian Bone Marrow Transplant Recipient Registry. We reviewed treatment regimens, survival outcomes, deliverability and toxicities. Primary endpoints included overall (OS) and progression-free survival (PFS). Cox proportional hazards models were used to test the association of survival outcomes with patient and treatment factors. RESULTS: The median (range) age was 30 (14-68) years and GCT histology was non-seminomatous in 84% of patients. International Prognostic Factors Study Group (IPFSG) prognostic risk category was very low/low, intermediate, high and very high in 18%, 36%, 25% and 21% of patients, respectively. Salvage conventional-dose chemotherapy (CDCT) was administered prior to HDCT in 59% of patients. Regimens included paclitaxel, ifosfamide, carboplatin and etoposide (50%), carboplatin and etoposide (CE; 28%), carboplatin, etoposide and ifosfamide (CEI; 6%), carboplatin, etoposide and cyclophosphamide (CEC; 5%), CEC-paclitaxel (6%) and other (5%). With a median follow-up of 4.4 years, the 1-, 2- and 5-year PFS rates were 62%, 57% and 52%, respectively, and OS rates were 73%, 65% and 61%, respectively. There were five treatment-related deaths. Progression on treatment occurred in 17%. In a univariable analysis, worse International Germ Cell Cancer Collaborative Group (IGCCCG) and IPFSG prognostic groups were associated with inferior survival outcomes. An association of inferior survival was not found with the number of high-dose cycles received nor when HDCT was delivered after salvage CDCT. CONCLUSION: This large dual-national registry-based study reinforces the efficacy and deliverability of HDCT for relapsed and refractory metastatic GCT in low-volume specialized centres in Australia and New Zealand, with survival outcomes comparable to those found in international practice.