Kant makes a large distinction between priori and a posteriori knowledge. Priori knowledge comes from our senses while posterior knowledge is a higher form of theoretical knowledge seen as independent from our senses. Posterior knowledge is a hierarchical advancement of our basic experiences of the data we collect from our environment. It is possible to call this abstract or theoretical knowledge that allows for projections about the nature of our world.
Knowledge in its priori form is more synthetic in the sense that it relates directly to our experiences. When the knowledge is posterior in form it takes on a more analytic approach. For example, we experience that rain hits the ground and makes a splat. However, through reflection we can review multiple experiences over time to learn that rain can make plants grow. We may have seen greener grass a day after the rain but without an analytical reflection we wouldn’t have been able to make the connection between rain and green grass.
Each person sees the world in slightly different ways. All prior experiences come into our existing filters and understandings. Without these filters and understands the information would not make a whole lot of sense. It would be as though someone would have a sensory integration disorder where the information is only information without previous context. It would be relatively useless to our needs because it is not processed properly. Therefore, our mind has a perception and this perception makes the world of difference in how we view information and make meaning from it to create behavioral responses.
Even though Immanuel Kant was not an outright empiricist his book helped in defining and developing the scientific method. Posterior knowledge should be tested to ensure that the data from our environment fit within these explanations. Where there are outliers to these theoretical constructs there would be a need to develop a stronger theoretical model. Hence the process is to develop the model based upon our experiences and then test those models to see if they adequately explain what is happening in our environment. When they don’t explain and predict consistently then there are other factors to consider.
Most importantly Immanuel Kant discussed the concept of morality as reason. In essence, all morality is based on the deduction of natural laws and principles. He certainly makes sense in terms of explaining that moral laws are often associated with societal structure and our concepts of right versus wrong. For example, it is wrong to steal because when one does this they destroy economic trust and this lack of trust can cause societal chaos. If we are not relatively sure that we can keep what we earn why would we put forward the effort? Perhaps it is better to become part of the stealing class or not put forward any effort at all? Since no society can exist without rules of interaction and engagement it would make more sense to enforce/reinforce the elemental beliefs of a society without necessarily forcing society to take any predefined vantage point of these root beliefs. Are there many justifications for not stealing? You only need to pick one regardless of your reasoning as it all ends at the same conclusion.
The book is heavy in terms of its knowledge and discussion. The concepts are theoretical by nature but have transformed the way people think. As you read through this book you will likely need to reread a few paragraphs as Immanuel Kant likes to have long winded rhetorical discussions. You can get temporarily lost in his train of thought. It is his way of connecting the information to create conclusions that others can agree with. Any student who wants to understand the underpinnings of scientific thought, psychological principles, or societal morality should pick up a book. As with all great works they are generally ignored upon their completion but end up transforming the world later.
All the preparations of reason, therefore, in what may be called pure philosophy, are in reality directed to those three problems only [God, the soul, and freedom].- Immanuel Kant
Kant, I. (2007) Critique of Pure Reason. Penguin Books: UK (Originally published in 1781) ISBN978-0-140-44747-7