Kant, in speaking of the use of analysis and synthesis in logic, lays down the test of all scientific inquiry. He says: ‘Analysis is the first and chief requirement in making our knowledge distinct. For the more distinct our knowledge of a thing is, the stronger and more effective it can be; only the analysis must not go so far that at last the object itself disappears.’
Truth being a unity, the science which demonstrates it must correlate all knowledge.
Science is not, therefore, an accumulation of isolated facts, or of facts torn from their natural relations. To know a thing scientifically is to know it in just relation to all other things. For science unites and demands the exercise of our various faculties as well as of our senses.
Science is proved knowledge. It is the study of causes and their relations applied to facts; but such proof can only be obtained by search which is in accordance with the laws of Nature—laws which are gradually discovered by our race.
Natural law is deduced from all the facts of human experience, in searching for and collecting which we must recognise the conditions under which we are placed, the limitations of the present phase of our intellectual powers, the gradual growth of conscience.
Science being proved truth, scientific method requires that all the factors which concern the subject of research shall be duly considered, in order to arrive at correct thought respecting the special subject of inquiry.
The application of scientific method necessarily varies, therefore, according to the subject under investigation.
Thus, the construction of a bridge and the calculation of an eclipse equally involve the bases of scientific method—viz., observation, deduction, and experiment; but each subject requires a special application of scientific method, suited to the varying nature of the subject of study.
Consequently, biological research, in order to be scientific, requires a special modification of method, because the new factors of sensation and consciousness come into play in biology—factors which do not exist in astronomy, or geology, in mechanics, physics, or chemistry.
In order to attain truth respecting biology, therefore, the facts concerning sensation and consciousness and their relation with, or the way in which these new factors modify the facts of, physics and chemistry must be carefully considered in this higher state which we call life, or the investigation is not scientific, no matter how interesting as an intellectual exercise.