In Scotland, any male of mature age, that is, of twenty-one years or more, can apply to become a Freemason. Following the practice of stone masons of previous centuries, a man of eighteen years of age might be admitted provided that his father is a Freemason and in 'good standing'. Men admitted on these terms and aged between eighteen and twenty one years of age are known as a 'Lewis'.

There are yet still other qualifications:

A belief in a Supreme Being: Every applicant must profess such a belief but Freemasonry does not define, or impose, a definition of a Supreme Being. Each individual applicant must define that entity for himself. Atheists and Agnostics cannot, therefore, become Freemasons. This belief is absolute and admits of no exceptions. Of course individuals might lie in this respect in order to gain admission and there is little that Freemasons could do to identify such men. All is taken on the honour of the individual concerned. In fact everything that a Freemason does in his private and public life must be honourable and Freemasonry encourages all members to behave in an upright and moral manner. Members are encouraged to support their individual faith.

A Members Obligation. Each and every applicant must be able to fulfil his obligations (financial, moral, and in terms of his time) to his family, his employment and his faith before he makes any commitment to Freemasonry.

Masonic 'Obligation': For in excess of 400 years Scottish Lodges have required an applicant to take a vow, or oath, on a holy book on his admission to Freemasonry. Such an oath, or obligation, is necessary in order to add sanctity to what is a serious undertaking and can be compared to; 'swearing the whole truth and nothing but the truth' in a court of law. Such oaths were common in many aspects of life 400 years ago when Freemasonry began and the Grand Lodge of Scotland continues that practice although many institutions have since done away with that necessity. As all men, who profess a belief in a Supreme Being, are eligible for membership the required oath may be taken on the Holy Book of each individual's faith. In multi-cultural societies it is common, therefore, to find Holy Books in Lodges, other than the Bible, on which candidates take their obligation.

How to Join: Scottish Freemasonry does not recruit members, although it is permissible for a member to discuss membership with individuals whom they believe would be a credit to the Craft. Otherwise the only way to become a member is to ask another Freemason. As existing members do not walk about with a badge stating: 'I am a Freemason' this might appear to be a paradox. The simple fact is that Freemasons do not seek out members who are unknown to them, it does not mount recruitment campaigns, nor does it ask its existing members to seek out new recruits. The reason for this lies, again, in the history of the Scottish Craft. The stonemasons Lodges of 400 years ago were for stonemasons only. Non-stonemasons became aware of the existence of Lodges and were curious as to what took place within them. As they were not stonemasons they were not automatically invited to join a Lodge but had to ask to become a member. This practice continues today - a man has to ask to become a Freemason.

Moral and Upright Men: This means that a man who has been convicted, in a court of law, of a serious criminal offence cannot become a Freemason. Anyone who is a Freemason who is so convicted is subject to Masonic discipline and may  be expelled from the Craft.

Membership: No man is permitted to use his membership to advance his own political, religious or business aims. For this reason Lodges do not allow members to discuss political, religious or business matters. Anyone who persists in doing so is in danger of expulsion. There is no doubt that one of the attractions of Masonic Lodges is the ability of all faiths, creeds and cultures to mix freely knowing that no-one is interested in the individual's social position, faith, or politics. This ability to meet with others, of various backgrounds has been one of the mainstays of Freemasonry for centuries. This, unique situation has been described as being: 'the ideal escape from the rat-race'.

As can be seen from the above anyone who cares to lie to a Lodge, but primarily to himself, can become a Freemason but he will have gained admission on a falsehood. There is, in fact, little that fellow Masons can do to identify such men. There has, no doubt, been many of such ilk in the past and the present (and no doubt there will be more in the future) and there is little that Freemasonry, per se, can about such cowans. In the course of time such individuals learn to appreciate the true value of Freemasonry for themselves, or if they do not, they generally leave the Craft of their own volition. It should always be borne in mind that Freemasonry is a voluntary organisation. Many join for a variety of reasons and find that it is not quite what they anticipated and leave without impediment.
Freemasonry practices the 'Brotherhood of Man' and this can surely be no bad thing in this modern, materialistic age?