"What's in a name? A rose by any other name, wouldst smell as sweet."--William Shakespeare
Perhaps that is so, and if so, why all the fuss about choosing the right magickal name or craft name? Indeed, why even bother to choose a name at all? What's wrong with just being "Sue" or "Bill" ?
Let's take the example of the rose. When you hear the word "rose" you get a definite picture in your mind, you see a color, you see the flower, you know what scent to expect, and you also know it will have thorns. Those are the attributes of a rose. So when I say "rose" and you hear "rose" we may not be seeing exactly the same mental image, but we will be talking about basically the same flower.
So it is with names, craft names and magickal names especially. Not every "Sue" or "Bill" is alike, and when you hear that name, it may not bring up any mental images for you at all. If you know someone already with that name, you will naturally think of that person, and compare them to this one. Magickal names, therefore, are to conjure up a mental image of the attributes of the name itself, or the God or Goddess associated with it. The same holds true with magickal names that are of plants or animals. Each has attributes that are beneficial and will bring those to mind when you hear that name.
People will take the name of an animal to encourage the good qualities of that animal in their personalities, or to strengthen tendencies they already possess towards those qualities. Not all qualities are desirable, however, and you need to remember when picking this name that you will also get the less beneficial ones along with the ones you are seeking.
For example, a rose has thorns. Many animals have sharp teeth and claws for defense or attack. Some are carnivores and prey on creatures smaller than themselves. Does this mean that if you take the name of a tiger (such as tigershadow) that you will become a bully? Probably not, but why ARE you taking the name? Be clear just what the attributes are, both the positive ones that you want, and also the ones that you may not like very much.
Our tradition usually encourages people to take on God or Goddess names as a craft name, especially for inner court working. This requires research in at least three different sources to be sure that all sides of this personality are known. You see, these names have been used for centuries, and myths have been told and retold, and there is definite energy associated with these names on the astral plane. The myths will give you clues as to how this Deity behaves, and what are his or her attributes. Three sources are the minimum needed because many books will give you slightly different versions or different stories. I was researching my first degree name and I had almost chosen a Goddess, when I came across a few stories where she was said to have eaten her children. I took that to be selfishness, (myths are almost never literal) and decided that as a mother of two, I didn't want to take on that much selfishness. A little is necessary for your own survival, but I judged that story to illustrate an attribute I didn't want to emphasize in my life. I kept looking and chose another name at that time.
Another reason to choose a magickal name is to let your younger self out to play, and to expand and allow your rational self to be the person you have always wanted to be. You are not the mundane person who goes to work from 9 to 5 everyday - when you are in circle, you let the magickal, spiritual, real you come out! A magickal name will assist you in this, if you are careful and choose the correct one for you.
From time to time, a student may ask a teacher or close friend to aid them in choosing a name, or in choosing between a few names that they like. That's fine if the person knows you well and will be honest with you, but please, don't ask another person to name you. This is too great a responsibility for another person. It's up to you to decide how you want to grow in the Craft, and what kind of person you wish to be. Others can help, but only by doing the research and the actual choosing yourself can you be certain that you have picked a name which will allow you to grow into it gracefully.
One last thought on names - when you are choosing this name, know that it will not be the last name that you choose. You aren't stuck with it for life! As you grow in the Craft and change, your name can change with you. Try not to take on more than you can handle at first. "Isis" is not a name to start with, as this Goddess is widely worshipped, powerful, and has a lot of hidden mysteries. You can end up as Isis as you grow in the Craft, but you will be much better off, and have less to deal with, if you choose a more local diety, or one that is less complicated. That will give you smaller changes that are easier to handle, and attributes that may be more smoothly integrated into your life.