How relevant are gestural components for Doctor Strange's magic?

Question

In both Doctor Strange and Infinity War, restricting a wizard's movements (using the Crimson Bands of Cyttorak, for example) has been the primary mean to keep them from casting any spells.

However, we see in Doctor Strange a specific wizard (Master Hamir) who can make magic with a missing hand. Hell, the movie's whole plot revolves around Strange understanding that he does not need to execute the moves perfectly, but simply believe in himself to cast magic.

It does not seem odd to me to suppose that one could make magic without hands at all, defeating all purpose in immobilizing a wizard. Yet, it works.

So, are gestural components really necessary for any wizard to make magic? Is there really any use in immobilizing a wizard?

I don't really expect to find a concrete answer to this in the MCU, so I will be accepting answers from the comics.

Answer 1

The MCU is a distinct universe from the comics, but draws abundantly from them.

Dr. Strange was created by Stan Lee and Steve Ditko. The latter's influences and sources of inspiration are the key to answer your question. Ditko wished to create a mystical character based on a mix of eastern esoteric and religious traditions.

For example, the Eye of Agamotto is strongly linked to the Snail Martys charm and amulet of Buddhism, especially in Nepali traditions. The fact that Strange and other dabblers in the occult often conjure powers from both good and evil sources, and use both black and white magic, is a display of influence from Taoism. And most explicitly, the setting where Strange first learns magic is Tibetan.

One traditional eastern practice that Ditko incorporated into the comics was the usage of mudras. From Wikipedia:

A mudra (muˈdrɑ); Sanskrit "seal", "mark", or "gesture"; Tibetan: ཕྱག་རྒྱ་, THL: chakgya) is a symbolic or ritual gesture in Hinduism and Buddhism. While some mudras involve the entire body, most are performed with the hands and fingers. A mudrā is a spiritual gesture and an energetic seal of authenticity employed in the iconography and spiritual practice of Indian religions.

The mudra most associated with Dr. Strange is the karana mudra:

The karana mudrā is the mudra which expels demons and removes obstacles such as sickness or negative thoughts.

This resounds with the powers of the Eye of Agamotto, which can dispel evil magic and reveal paths. Dr. Strange is also mostly immune to common diseases due to a mix of reasons.

It is made by raising the index and the little finger, and folding the other fingers. It is nearly the same as the Western "sign of the horns", the difference is that in the Karana mudra the thumb does not hold down the middle and ring finger.

He can often be seen using other gestures, for different effects. This has to do with different mudras having different meanings and purposes.

Since mudras have power of their own, we can imagine that they are as much a part of a spell or incantation as are words, thoughts, and material components. In some way, removing a mudra from a spell or replacing it with another mudra would be like removing or replacing a part from a machine - whether the spell will work, and how different its effects will be, will vary from spell to spell and from mudra to mudra.

If you wish to learn more about Steve Ditko and/or meddle with powers not comprehensible to mortals, a good suggested read is The Lesser Book of the Vishanti, by Catherine Yronwode.

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All I have said above explains the usage of mudras for the comics... In the MCU, their usage is never elaborated, and it is quite possible that things will stay like that. In cinema, things such as hand gestures for magicians are supported mostly by the Rule of Cool, and screen time is precious - so there is more pressure to leave it at that than to include exposition should we ever have a second Dr. Strange movie.

Answer 2

One standard explanation for this sort of thing which has been seen in multiple media, and not with just comic book characters, is that gestures or using a different language to cast spells acts as a way of concentrating. Think of it like the warm up swings a baseball batter or golfer makes; they don't need to do it, but it focuses the mind so they're ready to do it, and if it's interrupted it knocks them out of the zone.

The other rationale is that having to perform a small ritual and/or use certain language acts as a safety measure; the magician won't accidentally unleash a fireball by flipping someone the bird or making an idle comment.

As a magician becomes more skilled, they do it out of habit, but they're fully capable of not having to do it if they don't really, such as a skilled batter who for intimidation comes to the plate, assumes a hitting stance, and just stares down a pitcher waiting for the throw.