An analysis and comparison of everyday life and the domain of science reveals significant differences in their goals and in the cognitive means used to attain these goals. Students' lack of awareness of these differences can lead to pervasive learning difficulties in their study of science. Thus many students (a) have erroneous conceptions of scientific goals, (b) import goals and ways of thinking which are effective in everyday life but inadequate in science, and (c) devise ways of thinking ill suited to science. Additional complications arise because science taught in schools often differs both from actual science and from everyday life. Students' learning difficulties are thus increased because scientific goals are distorted and scientific ways of thinking are inadequately taught. The preceding analysis suggests some empirical investigations and instructional improvements.