A deeper and more prestigious meaning seems to attach to the term "know" in scientific research than in everyday life. The word is, as it were, pronounced with a totally different stress. Yet we shall soon see that "know" does not take on a new, special meaning in science, that knowing in science and knowing in ordinary life are essentially the same. The only difference is that in science and philosophy the loftier aim and subject-matter of the cognitive process lend it a greater dignity.