Every sentient being has a belief system. It may be an implicit system – where an individual's beliefs manifest themselves through the choices an individual makes – or an explicit system that can be written down and talked about. Everyone believes, even those who loudly proclaim that they "don't believe in anything": we make statements about the world by reasoning from axioms that we cannot prove, and the set of these axioms is precisely that individual's belief system.

The various belief systems are, at their core, incomparable. I do not consider some people as having a "better" set of axioms than others. One set may be more sound than the other, or more complete – but that only points to logical superiority, which is not necessarily what matters. I don't disrespect anyone for being inconsistent or for having blind spots. Therefore, the concept of "truth" is not well-defined across individuals. Truth is relative to an individual, but of course there are approximations that are consistent across individuals, especially if we talk about truth regarding testable everyday observations. For example, I hold that we cannot talk about whether the statement "God created the Universe" is true or untrue; however, we can talk about (and agree) whether the statement "if I punch the wall really hard, my hand will hurt" is true or untrue.

My axioms are as follows:

There are questions which we will never find answers to. These are questions about our Universe that are unanswerable to any being existing inside it. I consider the existence of these unanswerable questions to be equivalent to the widely accepted concept of God, or deity or gods.
I believe a theory exists that explains all observable phenomena. Until such a theory is found, I accept the prevailing scientific theories which aim to explain the most observable phenomena.
I define "truth" as a confidence around statements relative to my fundamental axioms with the following properties (the so-called "scientific method"):

All statements have a confidence which is a function of the statement's falsifiability and the volume of independent observations that support the statement
Statements that are logically inconsistent with other statements of nonzero confidence, or that are incompatible with direct observation have a confidence of 0

I make a distinction between an individual's belief system and his or her accepted dogma. While I consider dogma culturally important, I don't believe that the concept of "truth" is well-defined at the dogmatic level. For example, I don't believe that we can talk about whether the statement "Jesus came back from the dead" is true or untrue. While I don't consider any dogmas as "truth", such disagreement does not prevent me from respecting others' belief systems, which may include dogma.

I ask only that everyone chooses a belief system of their own, informed will, and that they don't impose their system on others (i.e. doesn't directly or indirectly prevent others from adopting a belief system of their own, informed will).

To end with, a quote.

I'm a highly organized pattern of mass and energy and when the time comes I will cease to be. The certainty of my death makes my life more meaningful.