Empiricism is the mode or method of philosophy that places the world observed through the five senses as the most real world and the reality we have the greatest reason to believe exists.

Perhaps there are more than the five senses, but science and general agreement on the issue rests at five. Some humans, such as a few that were blind since birth, have developed further senses such as a form of echolocation that would certainly qualify as a further sense.

The empirical philosophers are akin to scientists in that they typically believe the objective, external world of physical reality is the reality we have the most reason and evidence to suppose exists as it is given to us.

The empiricist would hold that what is "a posteriori" (Latin for posterior to) is of the greatest importance or of sole importance in developing concepts and gaining knowledge for a particular mind.

Rationalists, contrary to this, believe the world of the individual's internal mental world, or the world of phenomenal consciousness, is the most immediate and given.

Skeptics believe that both empiricists and rationalists are wrong to believe that any method of observation, be it objective or subjective in nature, is a guide to any understanding of reality because both methods could be flawed or simply wrong in combination.

Most philosophers have held that all modes of belief about reality tend to fall under one of these three, empiricism, rationalism, or skepticism, philosophical dispositions.

How can one prove the reality of objects or of the world, in general, that the senses sense? Are there not myriad examples in which we can imagine that the sensed world is some form of illusion or that one is dreaming, etc.?

Simply because it is agreed upon by yourself and other humans that something does exist is no absolute proof for that thing's reality.

Objectivity can be seen, by a skeptical philosopher, as something relying on rather grand assumptions about the true nature of the world we find ourselves in.

What if all reality is a product of a single mind and all beings in it are no more than the creation of your or my mind?

How do we know that we are referring to the same thing when we utter a word in a language about it? How do we know that others, even if they do exist as we think they do, perceive the world in the same way? Could there be properties of the world that are perceived in very different ways by everyone or by, perhaps, groups of people?

Empiricism, generally, is the view that all of our concepts and beliefs about the world are gained through the senses.

This does not limit the number of senses or their particular modes. Many creatures have many various senses and the empirical philosopher will lean towards the view that the paradigm or conceptual web of ideas held by any being is formed through experience of the world in which they develop or are exposed to.

Rationalists would hold, counter to this, that there are certain innate modes of understanding and categorizing that are independent of the sensed world that is encountered and that, for some beings at least, there is innate knowledge that was brought to the world of experience.

Perhaps our concept of height, for example, as a human being, is informed by the experience of being high atop some edifice but our understanding of fear of heights is genetically or innately encoded in our minds.

Without ever having experienced a high place, the rationalist may argue, the baby human has a fear of such relationships with the world that need not be experienced in order to have knowledge thereof.