It has gradually become clear to me what every great philosophy up till now has consisted of—namely, the confession of its originator, and a species of involuntary and unconscious auto-biography; and moreover that the moral (or immoral) purpose in every philosophy has constituted the true vital germ out of which the entire plant has always grown. Indeed, to understand how the abstrusest metaphysical assertions of a philosopher have been arrived at, it is always well (and wise) to first ask oneself: “What morality do they (or does he) aim at?” Accordingly, I do not believe that an “impulse to knowledge” is the father of philosophy; but that another impulse, here as elsewhere, has only made use of knowledge (and mistaken knowledge!) as an instrument. But whoever considers the fundamental impulses of man with a view to determining how far they may have here acted as INSPIRING GENII (or as demons and cobolds), will find that they have all practiced philosophy at one time or another, and that each one of them would have been only too glad to look upon itself as the ultimate end of existence and the legitimate LORD over all the other impulses. For every impulse is imperious, and as SUCH, attempts to philosophize. To be sure, in the case of scholars, in the case of really scientific men, it may be otherwise—”better,” if you will; there there may really be such a thing as an “impulse to knowledge,” some kind of small, independent clock-work, which, when well wound up, works away industriously to that end, WITHOUT the rest of the scholarly impulses taking any material part therein. The actual “interests” of the scholar, therefore, are generally in quite another direction—in the family, perhaps, or in money-making, or in politics; it is, in fact, almost indifferent at what point of research his little machine is placed, and whether the hopeful young worker becomes a good philologist, a mushroom specialist, or a chemist; he is not CHARACTERISED by becoming this or that. In the philosopher, on the contrary, there is absolutely nothing impersonal; and above all, his morality furnishes a decided and decisive testimony as to WHO HE IS,—that is to say, in what order the deepest impulses of his nature stand to each other.
Beyond Good and Evil, Friedrich Nietzsche
There is a video of Jordan Peterson spending 45 minutes explaining this passage by Nietzsche in Beyond Good and Evil. This suggests that it is a rich and difficult passage, but also that Peterson lacks concision at times. I will be brief in my attempt to explain this gist of it.
What Nietzsche is saying is that we all have impulses. These impulses are aimed at different things. We have an impulse to play, to conversate, to fight, to argue, to love, to entertain. Philosophers think that they are being impersonal and objective in their writing, but this is very far from the truth. They are simply reflecting the most dominant impulse within them.
Scholars and scientists can be interested in family, politics, or making money, but still be competent at what they do. In the end, they are just using their minds as a logical apparatus to solve problems. The problem with philosophy is that it gives us the illusion that it is grander and more pure than other things we engage our minds in, we feel that our philosophy is majestic, imperial, impersonal, but in truth, our philosophy is a representation of whichever impulses have won the battle within us. They are nothing but a reflection of who we are, and never an objective description of what the world is.