First Causes Are Outside The Realm Of

A Fact In Itself Is Nothing. It Is Valuable Only For The Idea Attached To It, Or For The Proof Which It Furnishes.

The Great Experimental Principle, Then, Is Doubt, That Philosophic Doubt Which Leaves To The Mind Its Freedom And Initiative, And From Which The Virtues Most Valuable To Investigators In Physiology And Medicine Are Derived.

All The Vital Mechanisms, Varied As They Are, Have Only One Object, That Of Preserving Constant The Conditions Of Life In The Internal Environment.

[those] Who Have An Excessive Faith In Their Theories Or In Their Ideas Are Not Only Poorly Disposed To Make Discoveries, But They Also Make Very Poor Observations.

In The Philosophic Sense, Observation Shows And Experiment Teaches.