My step-dad is an ISFP, and we are a lot of like in some ways, but in ways
we sense and grasp that other people don't observe. However, on the surface, I am more likely to be confused with an INTP by other people. My communication style is more insync with an INTP (Ne), but my core feeling seems to be more insync with ISFPs I know (Fi).
Comparing myself with my step-dad has highlighted the differences between the IxFPs though, so I'll point some of those further down.
Other differences that have been mentioned, but I'll give my take on it:
ISFP - focused on the moment, often base their opinions on personal experience & may distrust theory, enjoy more hands-on activities for the sake of the activity itself (as they enjoy the
process), often less verbal and articulate in writing, may seem more hedonistic, not idealistic, but more accepting of what is current reality (even if it frustrates them - hence the escapism through physical sensation), but may have "causes" that are more "close to home" and take a more practical, immediate approach to supporting them, often feel it's "good enough for now" as they are more aware of current, realistic standards. Se is impulsive and is more spontaneous with physical movement.
INFP - enjoy theory & the hypothetical & may even trust that over experience (as experience is always limited & narrow), future-focused with larger/universal ideals, may enjoy hands on activities but usually have an end goal in mind (more
results oriented), impatient with details but can get obsessed with them if it's something they care about (don't confuse obsession with details to being naturally observant of them), perfectionist tendencies. Ne has whims and is more spontaneous with ideas (which may lead to action).
So it kind of annoys me when people act like every person who has picked up a paint brush and who has talent in the visual arts is an ISFP. My step-dad and myself are both visual artists, and while he probably draws better because he practices more & is older/more experienced, my sense of color and taste level is far superior. I also dress much better than he does & I follow fashion and understand texture/material better (another stereotype about INFPs - that we dress worse). Both of us really like different foods/flavors, beauty/aesthetics, atmosphere and culture. My step-dad also loves language, and he picks up accents well & learns by hearing. I am much better with grammar and the written word though. I also express myself better verbally; my step-dad often gets frustrated when talking to people.
When it comes to music, I am by far the bigger fan. I have a substantial physical and digital collection of music, and I love live music. My step-dad almost dislikes listening to music, but when he was younger he played guitar. This illustrates the focus on the process vs. focus on an end goal: My step-dad did not play guitar to learn to write songs or because he loves music, but he just enjoyed strumming it when hanging out with his friends. I have no interest in musical instruments except to create - I would like to write a song, not play existing ones. This shows how my step-dad, an ISFP, and I, an INFP, often have similar interests/behaviors on the surface, but different ways of experiencing them.
Also, as I mentioned a bit in the list above, INFPs are not the only ones with causes. Most vegetarians and animal rights/environmental activists
I've known are SP, and many people note that ISFPs often have a special connection to nature (being so sensory oriented). INFPs are not the only Fi-dom on a mission. My ISFP step dad gets much more gung ho when it comes to his beliefs than I do. Being action oriented, he "hits the pavement" so to speak without much thought. I tend to mull things over and form longterm goals to build up to, which delays my action.
Oh yeah, and a lot of ISFPs are strange also. My step-dad is easily as odd as I am.
