Yes, we need to think critically to know truth. And science, even two second science, such we do by smelling a milk carton, for example, is investigative science. We rate the quality of the milk through our empirical investigation. To take it on faith, if a church leader tells us to drink the sour milk, we take the risk of injuring ourselves with bacteria.
We all know what we experience to be truth. Yet that is not the whole story. If you are at a table or desk right now, you know it is true that it is “solid.” But the atoms comprising the solid surface are mostly space. Space is the most present “truth.”
Your individual cells, all the way up to the cosmos, are composed primarily by space. We know of this truth, but we don’t operate according to it. We behave as though objects are solid, so we can function in the real world. For practical, (our) purposes, we, and objects of the world, are solid. Time is another such “experience.” Earth rises and sets and we have to live with these “timed” patterns.
We also know we dream each night. Our bodies evolved to be paralyzed during REM periods (dream) sleeping, so we would not act out our dreams, and wander into danger. But if we experience sight, sound, smell, and so on while dreaming, is this truly happening to us? No, but we rely upon sense stimuli, nevertheless.
We have learned to not always trust our senses. Science was developed to have an accumulative place for ideas to be proven true, or not. Science allows us to differentiate that which is improbable from the probable. This is the essence of Occam’s razor. What we experience, and can predict, as the most likely solution is likely “true.”
For many centuries, humankind has sought to define empirical experience, which is the basis of accumulated knowledge, and to distinguish it from other knowledge, based on hallucination, dreams, spirituality, and unexplained “experience”.
The system we have put in place, then, the scientific method is only to deduce, (and even then it is always presented as just a hypothesis) as to what is happening, so that knowledge can be built, and added on to, or science doesn’t work.
Most would argue that which you experience daily, is truth. In order to operate in the world, we need to trust our senses. We need to know that this is food, this is water, and this is poison, and so on. If we did not trust our senses, we, could not survive. We are not the only organisms, however, to operate according to what we sense. Many animals have senses far beyond ours in perception. Pigs and dogs have a greater sense of smell. Bats, cetaceans and others have keenly developed echo-location, which we have barely, if at all. Many argue that finely honed senses allow completely individual talents between, and even among, differing individual species.
By nature of our larger brains we have conceptual truth that often muddles our interpretation of everything we sense. What we store in our minds becomes truth, even when it is highly improbable. This is why charlatans never cease to have buyers and audience. They know that what we want to be true will often be stored as truth, in the mind, especially when it comes to those things that provide comfort and security. It is also the basis of all advertising and politics, and all conquering of peoples and resources.
Science, when it can be applied to interpretation, is a real asset. It allows us to think critically, and to make up our own minds as to whether someone is representing reality, or if they are somehow profiting from unreality. Always pay attention to what someone has to gain if they are making efforts to convince you of some “fact.”
To date, that which we have come to call Natural Laws are the best indicator of reality. Gravity is true, both to the math work, and to our experience. It is the same for biology, chemistry, geology and all those measurable “sciences.”
Many would argue that there is such a thing as spiritual truth, or the truth of art and humanities, the truth of faith, and so on. We can accept there are different ways to evaluate these truths. We can accept, just as is the case for science, to follow up on learning who has something to gain from every kind of truth. Many believe we suffer from trusting those who taught us to develop and conquer nature’s resources, rather than to think of them as God’s gift of creation to all living beings. This has led to overpopulation, pollution, water shortage, and habitat destruction crises world wide. Which do you experience as being true? For most of us, the true answer is both.
When what is to be gained is found to be neutral or just accumulated knowledge, the truth is likely sound. If someone, or some entity profits, the truth should always be observed with skepticism, and an openness to challenge assertions.