"Thoughts Without Content Are Empty, Intuitions Without Concepts Are Blind" 

From the Critique of Pure Reason - Kant

Kant's philosophical career reflects the breadth of his teaching and his interests. When, after 1770, he finally came to write the works for which he is most famous, namely the three Critiques, he addressed what he saw as the fundamental questions that cover human concerns: 'what can I know?', 'what ought I do?' and 'what may I hope for?'. His answers to these questions is marked by the changes he bequeathed to epistemology, ethics and aesthetics. Writing in the Critique of Pure Reason, Kant himself described these changes as a 'Copernican Revolution'. Some of his many other works focus upon the consequences of these foundational revolutions for moral behaviour, law, physical science and religious belief.  Kant refers to two powers or capabilities as understanding and intuition, respectively. Our minds must receive an object and understand it; only then can thought be made. It is only once objects are understood and thought of that concepts can be formulated, intuitions constructed, offering something new to the world. Kant introduces Sensibility as a prerequisite to understanding and intuition. 

However, it is not enough to merely receive sensations through one or more of the five senses for these provide a constant stream of information that is not necessarily processed by our minds. Sensibility thus becomes a mental-guided observation - an intuition made intelligible.