But even if nature were a limited system and we were able to get into possession of all the conditions under which any event within this system occurs, we should still be no better off, for the external conditions under which our imaginary system would be what it is, could never be known. The student of life, of chemistry, of physics land all others, would find their experience hedged in by an impenetrable wall, beyond which they could not go. In an unlimited world, however, there can be no theoretical limit to experience, and while at any time we are actually hedged in by our ignorance, this wall is fortunately capable of being moved by human powers, and the road to further exploration is clear for all who wish to go that way.
Since exhaustive knowledge in an unlimited universe is clearly unattainable by us, it follows that a scientific explanation is a growing explanation, and of necessity always incomplete. So far as it goes, we have a scientific explanation of life to-day, but it satisfies almost no one because the most important things remain unknown, and our explanations are inadequate to meet our practical let alone theoretical needs. These inadequacies have tempted many to fill out with art what they lack in knowledge, but the deficiencies of science, coupled with the certainty that there is no limit in a limitless universe, to what we may find out, to the man who is true to the scientific standard, are the greatest stimuli, for there is no joy equal to that which comes from extending the bounds of knowledge, for even though she tells us nought of "lunar politics," nevertheless, “all the things thou canst desire are not to be compared unto her.”
To many men the realization that the work of science is unending and that she can extend no hope of ultimate explanations, comes as a blow, but this is neither more nor less than the just reward of all who take the universe lightly. This particular limitation biological science shares with all her sisters, for her failure to give us anything else than the physical symbols of life is a shortcoming by no means peculiar to the application of scientific explanations to vital phenomena. The physicist might analyze hydrogen and oxygen with the same magical lens which we applied in imagination to man, and if present opinions are correct, he would see the constellation of electrons that constitute the hydrogen atom and the constellation that makes up the oxygen atom. If he were an experimental physicist, he might take an electron out of the hydrogen atom and replace it by one taken from the oxygen, and be surprised, or not, according to his preconceptions, that substitution makes no difference. Further analysis might tell him that the hydrogen
- Brooks, W. K., “Intellectual Conditions for the Science of Embryology,” Science, Vol. XV., pp. 453-454.