This link will give you one of the most fascinating learning experiences for young 6-yr old children. Children discuss very abstract thought that pertains to understanding big ideas about where feelings come from. Perhaps the word choice is not yet developed, but as they grow and mature, it will certainly come.
We all learn philosophy, directly or indirectly. We know that if it rains, you will get wet. If you walked outside a building and did not get wet, then it is not raining. We used a posteriori (experience driven) knowledge to draw this conclusion.
We know that the Sun will "rise" in the morning today, tomorrow, and every day for the rest of our lives. We used a priori (rational) knowledge to predict this bold conclusion.
Every subject area follows rules of logic. In math, you must know that when you add 2 objects to 2 other objects, you get 4 objects. Of course, we know this is not always true. If you add 1 raindrop to another, you get 1 bigger raindrop, but this is a relatively moot point.
Knowledge occurs either through experience or reason. Everything you truly understand required one of those 2 conditions; often both. You might think that you know that F= ma, but if you did not reason the meaning of the equation or experience a lab showing this, you do not really know it.
It amazes me that never in the pursuit of a high school diploma, does philosophy come up as an important subject area. It is just as important as reading, writing and arithmetic. Philosophy begs the question of why we take it for granted that 2+2 = 4, or that the Sun rises every morning. Philosophy is the foundation for any real knowledge; it is also the common link for all Wikipedia articles. Try clicking on the first link of any Wiki article, not including terms in parentheses or disambiguations. Repeat this several times, and eventually you will find philosophy.
You cannot truly understand how we know that a scientific "fact" is true without understanding the roots behind it. Everything you read in a science textbook was either derived mathematically (reason) or experimentally tested several times without failure (experience). You must also understand that nothing you have learned in science is a true "fact." The concept of force was created to make it easier to understand how to predict an object's motion. Momentum was created to help predict collision results. Energy was created to determine how fast an object could travel given certain parameters.
You cannot truly understand that 6 million Jews died in the Holocaust without understanding the writings of eyewitnesses who saw it happen (experience), or without understanding the mathematical analysis used to compute such number (reason).
You cannot truly understand that a sentence must contain a noun and a verb without understanding that a statement lacking such is useless (reason), or that writing would be difficult to understand without such components (experience and reason). You also know that even with such parameters, a sentence can still be meaning less. Ex: Colorless green ideas sleep furiously (famously stated by Noam Chomsky). Sure, there is a noun and verb but it is utterly meaningless.
Experience and reason are the key henchmen for philosophy; they enforce the creation of knowledge that we take for granted. Any time you struggle to accomplish a learning goal, it is because you lack the appropriate knowledge or experience to fuel such knowledge. Nothing you learn in school is "new" information; it is simply a reorganization of things you already understand. You understand that waves exist because you hear them; you understand that the derivative of x^2 is 2x because you know what both equations look like and there was never a time in mathematics where the "correct" answer is not consistent with what you know (unless you are confused).
In order for more effective education, I firmly believe that philosophy should be of utmost importance to learners as young as Kindergarten and 1st grade. It should be a core subject, for all real knowledge is built through understanding how knowledge is built.
Is the glass half empty or half full? Neither. It is twice the volume of the fluid inside.