Examines the influence of phenomenalism from a realist perspective and its offshoot, operationalism, on concept formation in biology. Compares the basic tenants of phenomenalism with those of realism. Contains 69 references. (DDR)

Argues that the paradox of mathematical knowledge--that mathematics cannot be separated from empirical experience and yet cannot be explained by empiricist epistemology--can only be resolved if the causal interactions between knower and environment are accepted. Contains 26 references. (DDR)