If you are wondering what Humanism actually is, then a good place to start is the Wikipedia page on the topic, it starts with a quick summary …
Humanism is a philosophical and ethical stance that emphasizes the value and agency of human beings, individually and collectively, and generally prefers critical thinking and evidence (rationalism, empiricism) over established doctrine or faith (fideism). The meaning of the term humanism has fluctuated, according to the successive intellectual movements which have identified with it.[1] Generally, however, humanism refers to a perspective that affirms some notion of a “human nature” (sometimes contrasted with antihumanism).
In modern times, humanist movements are typically aligned with secularism and with non-theistic religions.[2]
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You might perhaps wonder where it all fits in with other labels such as Atheism and also Skepticism.
Atheism is simply a conclusion. When faced with a god claim, it is the rejection of that claim due to the observation that the god claims do not have any valid objective evidence. This stance says nothing about anything else, the entire scope is just this one conclusion.
Skepticism is a methodology that advocates that the information we have needs to be well supported by evidence, and so when faced with various claims such as aliens, bigfoot, ghosts, gods, psychics, miracles, etc… the available evidence would be examined. If for example, no conclusion can be reached due to the lack of evidence, then the most honest answer possible is “How interesting, but I don’t know”, and resists the leap to a specific conclusion. Oh and as a side note the word can be abused, for example the term “climate change skeptic”, is not skepticism, but rather is denial and rejection of the prevailing scientific consensus and the associated evidence.
So if you just happen to be a person embraces human reason, metaphysical naturalism, altruistic morality and distributive justice, and consciously rejects supernatural claims, theistic faith and religiosity, pseudoscience, and superstition, then you are in fact a Humanist – congratulations, because today, the longest brightest day of the year, is yours to enjoy and celebrate.
Religious dogma in all of its various forms has failed humanity, but there is truly a better way. Living up to the ideals and making a better life for all is indeed something to strive for, so lets band up together and encourage each other to do so.