Much of this must lie in his first adventure during ‘Castrovalva’ where a child taught him to see the title city as it really was. From this moment forth he had to open his mind, realising how much he didn’t know.
Time and again this humble attitude stood him in good stead, particularly during ‘Kinda/Snake Dance.’ This rebirth made the universe exciting and new to the Doctor. There was still plenty to discover.
More than ever the Doctor travelled for enjoyment. When the TARDIS failed to go where he wanted he still took the time to explore, encouraging his companions to appreciate their surroundings.
Inheriting a full set of companions the Doctor was more of a friend than a mentor or father figure. First impressions are important and Nyssa, Tegan and Adric certainly proved their worth, protecting him through the first difficult hours of his regeneration when he was most vulnerable.
He was much more likely to listen to his companions, giving advice rather than lecturing. The Doctor’s emotion connection was evident in the heated arguments that could arise when they disagreed.
Trouble seemed to find the Doctor, rather than the reverse. This Doctor was rarely charged with missions by higher powers, other than the distress call issued by the White Guardian in ‘Enlightenment.’
Even with the events of ‘The Arc of Infinity’ and ‘The Five Doctors’ he remained true to his original intent. Offered the role of President again he much prefered the prospect of going on the run again in a temperamental TARDIS.
The 5th Doctor did suffer more than his fare share of tragedy. Adric was the first companion who had travelled with him for a significant length of time to die, his loss effecting everyone in the TARDIS.
Tegan left him because she couldn’t stand the trauma she experienced by his side. She said it was no longer fun. The Doctor must have questioned what affect travelling with him had on his companions.
One could hardly blame Tegan for leaving. Death surrounded the Doctor. Perhaps his greatest failure was the events of ‘Warriors of the Deep.’ Only one person is saved during the adventure and the Doctor is forced to commit an act which he’d earlier argued was genocide.
“There should have been another way,” he says sadly before they leave.
Was this a defining moment for the Doctor? Did he realise that he needed to be someone different in order to save lives? Looking at how other incarnations of the Doctor’s view him can shed some light on how the 5th Doctor saw himself.
Upon regenerating the 6th Doctor is relieved, believing that his previous incarnation wasn’t him at all. Had he come to regret his choices? Can the more proactive 6th Doctor be seen as a reaction to the 5th Doctor?
Several regenerations later the 10th Doctor would meet his younger self and confide that he enjoyed being the 5th Doctor most of all. Bear in mind that the 10th Doctor was often defined by his regret and guilt over his actions during the Time War.
Did the 5th Doctor represent a time in his life when he didn’t have all that responsibility? When his youthful exterior allowed him to enjoy being young? Whatever the truth no Doctor could afford to have the freedom the 5th Doctor did.
In contrast the 6th Doctor was boastful and egotistical. His behaviour and garish clothes announced his presence where ever he went. By this stage he viewed himself as an expert on most topics, even taking up the challenge of trying to repair the TARDIS.
Although he did find time to take some pleasure trips many of the 6th Doctor’s adventures saw him actively following an agenda. Whether responding to distress calls or investigating a mystery he strode from the TARDIS with purpose.
The 6th Doctor was more than willing to get his hands dirty when fighting evil. During his unstable regeneration he briefly believes that Peri is evil and attempts to strangle her. Although he was never again as violent it was a good indication of what was to come.
This Doctor would take up arms against his opponents, push them into acid baths and otherwise take extreme measures. He rarely displayed any remorse or hesitation in taking these actions.
Just as before, this crusading Doctor eventually found himself on trial, forced to defend his own actions. The adventure he chooses to defend himself is ‘Terror of the Vervoids’. In his eyes this is the perfect example of the good he does but the Valeyard is quick to point out he committed genocide by wiping out an entire race.
During the Trial the Doctor makes two startling discoveries. Firstly that the High Council has tried to conceal their part in the fiery solar flare that devastated Earth and secondly that the Valeyard is possible further incarnation of himself.
This startling information taught the Doctor two things. That absolute power leads to corruption and that evil lay within him. His anger at his own people indicates that the Doctor didn’t count himself as one of them. It does, however, signal that the Time Lords fall into the same category as his enemies.
Should we infer anything from the fact that the Doctor doesn’t have any direct involvement with Gallifrey until the Time War? Although irregular the 3rd, 4th and 5th Doctor all had involvement with their home world, yet the 7th has no contact at all.
Did the Doctor deliberately isolate himself from his own people for fear of their corruption affecting him? Did he come to mistrust anyone with great power and did this inform his actions in his next incarnation?