All approaches at a higher level are suspect until confirmed at the molecular level. - Francis Crick

I argued that it was important not to place too much reliance on any single piece of experimental evidence. It might turn out to be misleading, as the 5.1 Å reflection undoubtedly was. Jim was a little more brash, stating that no good model ever accounted for all the facts, since some data was bound to be misleading if not plain wrong. A theory that did fit all the data would have been "carpentered" to do so and would thus be open to suspicion. (pp. 59-60)

Philosophers have been especially concerned with the problem of consciousness—for example, how to explain the redness of red or the painfulness of pain. This is a very thorny issue. The problem springs from the fact that the redness of red that I perceive so vividly cannot be precisely communicated to another human being, at least in the ordinary course of events. If you cannot describe the properties of a thing unambiguously, you are likely to have some difficulty trying to explain these properties in reductionist terms.

The ultimate aim of the modern movement in biology is in fact to explain all biology in terms of physics and chemistry.