Quite often does the radical physicalist postulate the "human perception = perception of all in existence" methodology, hence I wanted to focus on the phenomenal question, "Is there more than this life?" If one was to make this judgment according to his own dimensions, by the scientific method, he would have to go by what is known about this life in order to conclude another life, or lack thereof. Contrary to popular belief, the amount of strength for other existing realities or dimensions exceeds the amount of strength for this reality existing as the one and only reality.
Indeed it is faithful to merely assume multiple existences of such, however, assuming there is only one when the cause of one's own existence is not proven requires a great deal of faith and to an even higher degree. An orphan unaware of their biological parents would be very faithful to assume that they had no biological siblings when there is absolutely no declaration for the supposition. Conclusively, assuming whether or not this is the only reality is merely half the battle for both arguments, yet, as the orphan argument demonstrates, the opposing argument is the position founded upon ignorance.
Even if one did not believe in a creator, but rather any theoretical origin of the universe from either an accidental cause or absolutely nothing, there is nothing more to declare that the accident cannot happen in other instances into other universes apart from the current universe. The existence of the present reality, from either an accident or nothing, is a piece of evidence for the existence of other realities as there are no defined restrictions that determine such a chance singular. Apart from any chance-based theories, intelligent design is quite self-explanatory in one's considering of the potential existence of other dimensions.
Martin Heidegger's phenomenological assertion about death, or mortality, implies that "death does not come as an end"; however, if conclusively one is once nonexistent to this reality, yet he forms a state of being to this reality, how is it that he will someday become nonexistent to this reality as interpreted by biological science? Some might argue that imaginary pink unicorns are nonexistent to this reality, but provided is no evidence that they are existent in another. However, pink unicorns were not born into a conscious being of this known reality as humans were, hence those of being mysteriously cross this reality as unicorns do not. A tangibly existing thing, such as a conscious human, becomes a part of this reality, and passing through (from birth to death) is support for other realities. This is so because one does not have an immortal existence as defined by the properties of this life, yet one is indeed a being in itself that, apparently, moves into and from this life. Further provided is evidence that this universal reality is limited to and from specific properties that other local realities, such as humans, are capable of losing and/or gaining.
The only premise one has for the conclusion that the current reality is the one and only reality is based on the fact that one cannot consciously comprehend or perceive any other realities. For those who limit existence to perception, this is a contradiction because one cannot comprehend not existing in a reality of some sort. In other words, the human comprehension, in its incomprehension of not existing, inherently directs the mind to a future reality. Often used is the common notion, "Perceiving things is how we know they exist." In that case, and on the contrary, it is more so humanly logical to conclude that there are other realities by one's incomprehension of not being. Putting this idea to the test, one should try imagining not existing at all. It is impossible because there is a disposition thus imagining blindness, muteness, numbness, and deafness, which under such circumstances, would still be some form of existence no matter the combination. Human senses do not define existence; they merely detect certain properties of this universe. Because one cannot comprehend not existing beyond the current reality but will indeed move beyond it someday, by the common physicalist notion that human perception defines existence, one "perceives" that one can only move somewhere else rather than into nothingness.