It is my belief that what we accept as real may not always be because there are many realities. This text is not meant to be religious or in other ways non-scientific, but some of the thoughts forwarded may tend to be so as they are well beyond the limits of modern science. Please also notice that I have written this text entirely out of interest and that I have no formal knowledge of the themes discussed.

To get going, let us have a look at a paradox with two lines (above). Most people will see just that, two lines with different endings and different lengths. Before I added the endings, however, the two lines were of equal length. This raises a question: are the lines really just as long? To answer this we must have a look at different kinds of reality.

First of all, everything that we sense has a subjective and an objective reality. The subjective is how we interpret the object, for example that the two lines are black. The subjective reality of an object says nothing about its objective properties as the subjective properties have little to do with the actual object. When you see, smell, hear or in other ways sense an object, it is your senses, electrical currents and chemical reactions in your brain that enables this. In this sense, your dreams are real because you sense them. However, your dreams do not have objective properties, such as being able to create or destroy other major physical things, and thus they are not real.

This means that the screen you are looking at right now is not really a computer screen. What you see is the subjective property of your screen which in fact really is a stack of parts, atoms, quarks and so on into (almost*) infinite small units, which you have chosen to call a computer screen. Your mind makes an illusion for the subjective properties it believes the computer screen has. The fact that popular reality is based on illusions can very easily be proven by picking your screen apart: suddenly, what formerly was a computer screen has become a stack of parts. The screen has all of a sudden dissapeared and you are left with exactly the same components but it is something else: the illusion has changed.

This, however, must mean that we can actually change or alter reality, though only for ourselves. If we manage to overcome these illusions, or perhaps only change them, a dirty piece of kitchen equipment would be clean according to our illusions, which are just as real as anybody else's illusions. Some people claim that this is how Jesus did miracles and what made Buddha a holy man, an interesting thought but also an unsupported claim.

To sum up what we have learned so far, for something to be real, at least one of these must be true:

• It must be possible to directly perceive the object through one of more of the five senses (subjective)
• It must be possible to directly perceive the object through one of more of the five senses scaled by a scientific instrument (subjective)
• It must affect something else so that either of the points above will be true (subjective/objective)

Another question which we can discuss, not directly related to reality, is the properties of space and time. We can simply ask ourselves what is now? First of all, we should consider that time is, alike most other things, relative. As described by Einstein, time would slow down and eventually stop as you accelerate towards the speed of light. This must mean that in some way, time is dependent on some kind of illusion, thus making it a part of the subjective reality we have discussed above.

Your illusions of time are dependent on a few simple factors. For example, your perception of time seems to change with your metabolism, explaining why time passes so fast when you are fast asleep. Absolute time, an objective time, in a sense, should also exist as can be seen from the decay of radioactive materials (large quantities of the same material will have the same half-life), ageing of the human body and other such factors.

Space, on the other hand, also confuses our understanding of time and can alter the meaning of 'now' by the theories of relativity. The concepts are best explained by space-time diagrams:

The above figure is a space-time diagram for a two-dimensional space (no altitudes mapped as his would require a fourth dimension to our drawing which is impossible without an animation) where your current position in space and time is at the meeting point between the two cones (0,0,0). Every event in your past - or every event tht has influenced on your current situation - is included in the lower cone whose boundaries are determined by the speed of light (because the speed of light is the fastest by which information can travel). Every event in the futurte on which your current position and situation will or can influence is included in the upper cone, whose boundaries are also determined by the speed of light.

When you interact with or sense something, it is evident that it is within our spacetime cone. The above illustration shows how two events (for ease of understanding, they are labeled 'you' and 'someone else') can interact as their respective spacetime cones meet. This, of course, has many implications, and one is that nothing can be observed without delay (though the delay may be incredibly small), a concept which tends to be confusing. Other parts of the Theory of Relativity also prove the inexistence of simultaneity.

Other questions, however, are perhaps more significant to our understaning of reality and to most people's philosophy of existence because the above ideas tend to be very abstract. Death and its implications, for example, eventually become relevant to most people. Most religions have some explanations of this, but we should also consider the scientific and philosophical aspect (though discussion on the subject often border psuedo-science. Be aware!). The primary question is whether you have a soul, as described in the Bible and many other religious scripts, or not. Can we apply our recently developed model of reality? For something to be real it should affect our senses or affect something that affects our senses so that we can percieve it. A soul does not fulfill this, but cannot be completely disregarded yet: in support of the concept of a soul, it could be argued that we do not sense the sould because the soul contains our senses. Therefore, the ideas we have already established are largely irrelevant and/or inapplicable to problems regarding the existence of our soul and we will need to see things very differently.

Another approach is that emotions and the human psykie cannot be fully explained by science. Many supporters of such ideas are romantics and wish to belive that there is something more to mankind than merely chemistry and physics, but many anti-reductionists are intelligent people and their ideas should not be ignored.

The last apporach which I will comment, is to ignore the idea of a soul but see life simply as an accident or a random event. In this situation life starts as the sprem cell from your biological father melts together with the egg cell from your biological mother, and life ends when your heart stops beating. Between those moments you are alive and outside those boundaries you are dead and only existing in a past part of space-time. Such a view, however, offers little comfort and is often subscribed to by insecure and unknowing people as an argument for carelessness, but can also be weighty.

Over all, all the different levels and models of reality that we have studied in this text, and the different applications of these that we have seen, lead us back to one simple explanation: illusions. Illusions are probably based on a combination of your genetics and experiences. In the end - unsurprisingly - I have reached no propper conclusion, but established a set of ideas and concepts on which models and understandings can be built.

* according to quantum mechanics, nothing can be broken into infinite small parts.