Is there a purpose?
It would be unwise to attribute a sense of purpose to the immaterial universe, if by purpose we mean some future 'goal' or 'objective' to fulfill. The universe, which comprises of the fundamental particles and the forces which emerge due to their interactions, does not think about the future since on its scale it cannot. The universe evolves according to small scale and large scale physics. Some of this physics we understand very well, some we do not and there are missing gaps in our physics which we cannot even begin to picture what it would look like. While there are new theories and experiments to create and conduct we can never invoke any theory of mind and apply it to the grand scale of the universe, it is void of a conscience
I believe the meaning of purpose incorporates a theory of mind and can only sensibly be used in specific terms for living organisms or products of some general selection process.
Day to day I live my life thinking that I exist in a vast, almost (we don't yet know) timeless and cold (average temperature of universe if about 2.73 K or -270.42 C). I assume the universe evolves purely physically and hence obeying mathematical laws.
What about purpose in living organisms?
Looking throughout the animal kingdom there is undeniable purpose in their actions, thoughts and communication. A bird foraging the ground for nutritious seeds or an antelope expending great energy to escape the claws and jaws of its oppressor, life goes to exhaustive efforts.... but why?
For survival of course. Each creature tries to do its best with what it has in order to survive. This is the general answer many will give and to a certain extent it is true, but it misses the overarching purpose of life.
We can say that each creature acts as a protective vehicle for its genes, snippets of DNA which tell proteins how to build and maintain the body, shielding it from the harsh external environment. Creatures go to great extent to survive and have sex so that their genes are copied and looked after in future generations. Living organisms are programmed by genes for the continuation and prosperity of their genes. The creature and species to which it belongs do not play the main role in life. The singular purpose of a living creature is to ensure it passes on its genes and increases the chance of their 'survival'.
The purpose of a single gene is to increase its share in the gene pool, since it is in competition with other genes. A gene is a funny little thing, solely based upon the structure and behaviour of the DNA molecule, it has gained the power of replication and somehow it 'wants' to replicate itself as much as it can.
Obviously a gene cannot really want, the same as you and I, or realise its own purpose but the natural forces in motion make it so. It seems 'purpose' has risen from that which had none, i.e. the basic constituents of the universe.
The origin of DNA and the gene may have been completely accidental and it is likely that this is the case, since over billions of years the primordial soup has been able to explore its phase space and over time it becomes more likely to stumble across a configuration which creates a molecule which can replicate itself. The earth has just the right conditions for life to begin and flourish, it just takes the right abundance of molecules and time for it to happen.
Like is an accident. The origins of purpose itself is based upon the replicating power of the gene.
The justification for a liberal, inclusive and educated society
When I say liberal I mean it in the idealism sense of the word, the promotion of the freedom from tyranny, freedom of expression and the protection of individuals from physical impingement of their rights to live a free life.
I was influenced hugely by 'On Liberty' - John Stuart Mill and I have always used the principle : 'We are free to do as we wish in so far as it does not coerce another human being'. To protect this principle in practice we have the law, which should punish those who do coerce or cause physical harm to others.
Many will see an apparent contradiction, since punishment is a form of coercion and hence we seemingly have to violate the principle in order to protect it. But without this protection from an elected state (otherwise they will become a tyrannical state) the principle dictates a sort of a anarchy, where if coercion is not punished a primitive society will ensue where the strong will rule and tyranny will no doubt take shape.
The best compromise is to avoid any form of tyranny and form a state, chosen by its people, which allows freedom as long as it does not impinge the freedoms of others. Complete freedom, quite confusingly will lead to a state of tyranny. From human history we can see why we have favoured a more liberal democratic state.
As a direct consequence of the principle which a liberal democratic state should have at its core we have to be inclusive to those of varying ethnicity, sexual orientation and different views of life. Those who are different are allowed to be in so far as they do not violate the founding principle of the state. Me being e.g. black, gay and religious should be perfectly tolerable, if I cause harm to others I will receive punishment, not from the people but from their elected government. Punishment should only be dependent on the severity and details of the crime, not on the ethnicity, sexual orientation or religious affiliation of the person in question.
While migration and immigration may be monitored for economic reasons, policies regarding this should not be tainted by prejudice since it will not necessarily have the best economic and educational impact. Encouraging a multicultural society will lead to sexual diversification of genes, acquiring differing viewpoints on policies and science and also lead to the assimilation of different cultural traditions... which could lead inhabitants to live a healthier and happy life.
Education, along with health, should be the main topics of discussion for the state and the people since it is with quality and rigorous education that an individual may enhance his/her chances of living a healthier and happy life but also play a contributing part to society. Acquiring the ability to reason and question ad test hypotheses about the world is essential to a safe and functional society.
Reason can trump some of our more embarrassing physical instincts which may lead us to commit harm to others or ourselves.
A dismissal of all metaphysical, supernatural and fictitious entities
I can only say that objects or physical manifestations of forces exist if and only if there is a large body of empirical evidence supporting their existence and there is no empirical evidence ruling them out.